Mike Veach, a whiskey historian in Kentucky, said many of the Maryland distilleries before 1906 were actually rectifiers — plants that bought unaged whiskey from elsewhere, then redistilled it, or aged it, or added something to it to make a final product they could legally call whiskey.
|
|
Selenium rectifiers used in 1950s MADDIDA computer Selenium rectifier from 1960s. Each plate is 1-inch square. Radio and television receivers used them from about 1947 to 1975 to provide up to a few hundred volts of plate voltage. Vacuum-tube rectifiers had efficiencies of only 60% compared to the 85% of selenium rectifiers, partially because vacuum- tube rectifiers required heating.
|
|
These solid state rectifiers have since completely replaced mercury-arc rectifiers thanks to their higher reliability, lower cost and maintenance and lower environmental risk.
|
|
Selenium rectifiers have no warm-up time, unlike high-vacuum rectifiers. Selenium rectifiers were also cheaper and simpler to specify and install than vacuum tubes. However, they were later replaced by silicon diodes with high efficiencies (close to 100% at high voltages). Selenium rectifiers had the capability to act as current limiters, which can temporarily protect the rectifier during a short circuit and provide stable current for charging batteries.
|
|
The development of vacuum tube technology in the early 20th century resulted in the invention of various tube-type rectifiers, which largely replaced the noisy, inefficient mechanical rectifiers.
|
|
Metal rectifiers have been replaced by silicon diodes in most devices, however there are certain applications where the replacement of metal rectifiers with silicon units has proven impractical. These are mostly in electroplating, aluminium smelting and similar high-current low-voltage industrial applications, where the lower forward voltage drop of metal rectifiers is more important than their reverse breakdown voltage. Many purpose-designed transformer-rectifier ("Rectiformer") units were specifically designed around the characteristics of metal rectifiers, and substituting silicon rectifiers would necessitate replacing the complete assembly. As is the case with many other industrial processes, it is often considerably cheaper and more convenient to pay someone to manufacture replacement "legacy" metal rectifiers than to replace the rectiformer.
|
|
Hence, metal rectifiers are still manufactured in small quantities today.
|
|
Produced since 1981. Differs from ER9M by natural air cooling of rectifiers.
|
|
Before about 1905 when tube type rectifiers were developed, power conversion devices were purely electro- mechanical in design. Mechanical rectifiers used some form of rotation or resonant vibration driven by electromagnets, which operated a switch or commutator to reverse the current. These mechanical rectifiers were noisy and had high maintenance requirements. The moving parts had friction, which required lubrication and replacement due to wear.
|
|
Metal rectifiers were also used as envelope detector (AM demodulator) diodes in radio receivers. The WX6 Westector was a typical example. It was about the size and shape of an AAA battery, with threaded posts at each end to which connections were made. Selenium rectifiers were once widely used as high-tension rectifiers in transformerless radio and TV sets, before cheaper silicon diodes became available.
|
|
Selenium rectifier Once common until replaced by more compact and less costly silicon solid-state rectifiers in the 1970s, these units used stacks of oxide-coated metal plates and took advantage of the semiconductor properties of selenium or copper oxide.H. P. Westman et al., (ed), Reference Data for Radio Engineers, Fifth Edition, 1968, Howard W. Sams and Co., no ISBN, Library of Congress Card No. 43-14665 chapter 13 While selenium rectifiers were lighter in weight and used less power than comparable vacuum tube rectifiers, they had the disadvantage of finite life expectancy, increasing resistance with age, and were only suitable to use at low frequencies. Both selenium and copper oxide rectifiers have somewhat better tolerance of momentary voltage transients than silicon rectifiers.
|
|
Other uses of the metal include high-energy lasers, vapour glow lamps, and vapour rectifiers.
|
|
With the development of inexpensive high voltage silicon rectifiers, this technology has fallen into disuse.
|
|
Single-phase rectifiers are commonly used for power supplies for domestic equipment. However, for most industrial and high-power applications, three-phase rectifier circuits are the norm. As with single- phase rectifiers, three-phase rectifiers can take the form of a half-wave circuit, a full-wave circuit using a center-tapped transformer, or a full-wave bridge circuit. Thyristors are commonly used in place of diodes to create a circuit that can regulate the output voltage.
|
|
High-power rectifiers use mercury vapor to achieve a lower forward voltage drop than high-vacuum tubes.
|
|
Some more perylene based organic rectifiers with PEG (polyethylene glycol) swallowtails have been synthesized in Mattern's lab by Ramakrishna Samudrala.Samudrala, Ramakrishna (2008), Ph.D. thesis. University of Mississippi These rectifiers would allow the rectification to be measured with flexibility. Single molecules bonded covalently to gold have been studied by scanning tunneling spectroscopy and some of them are unimolecular rectifiers, studied as single molecules, as shown by the groups of Luping Yu (University of Chicago) and Ashwell (later at Lancaster University, UK).
|
|
Produced since 1961. In difference of ER9, the rectifiers were placed in car bodies not in passenger space compartments.
|
|
Rectifiers yield a unidirectional but pulsating direct current; half-wave rectifiers produce far more ripple than full-wave rectifiers, and much more filtering is needed to eliminate harmonics of the AC frequency from the output. Half-wave rectifier The no-load output DC voltage of an ideal half-wave rectifier for a sinusoidal input voltage is: where: : Vdc, Vav – the DC or average output voltage, : Vpeak, the peak value of the phase input voltages, : Vrms, the root mean square (RMS) value of output voltage.
|
|
Compared to later silicon or germanium devices, copper-oxide rectifiers tended to have poor efficiency, and the reverse voltage rating was rarely more than a few volts. A number of rectifier discs would need to be used in series to provide an adequate reverse breakdown voltage figure - a bridge rectifier for a 12V battery charger would often use 12 metal rectifiers. Selenium rectifiers were generally more efficient than metal-oxide types, and could handle higher voltages. However, considerably more skill was required for their construction.
|
|
PWM rectifier is an AC to DC power converter, that is implemented using forced commutated power electronic semiconductor switches. Conventional PWM converters are used for wind turbines that have a permanent-magnet alternator. Today, insulated gate bipolar transistors are typical switching devices. In contrast to diode bridge rectifiers, PWM rectifiers achieve bidirectional power flow.
|
|
High-voltage selenium rectifier Specially designed selenium rectifiers were once widely used as EHT rectifiers in television sets and photocopiers. A layer of selenium was applied to a sheet of soft iron foil, and thousands of tiny discs (typically 2mm diameter) were punched out of this and assembled as "stacks" inside ceramic tubes. Rectifiers capable of supplying tens of thousands of volts could be made this way. Their internal resistance was extremely high, but most EHT applications only required a few hundred microamps at most, so this was not normally an issue.
|
|
Also, the homopolar generator is unique in that no other rotary electric machine can produce DC without using rectifiers or commutators.
|
|
Development of high-current rectifiers required leadwire materials and glass with very similar coefficients of thermal expansion in order to prevent leakage of air into the envelope. Current ratings of up to 500 A had been achieved by the mid-1930s, but most rectifiers for current ratings above this were realised using the more robust steel-tank design.
|
|
It made alternators. In the 1960s, around 60% of its products were exported. The alternators are fed by full-wave bridge rectifiers.
|
|
Unit: Fan wheel. Placed: On splitter's rotor(?). Purpose: Cooling rectifiers, reactors, and transformers. The rotational frequency of the splitter is 1495 rpm.
|
|
Mechanically, the EU20 was identical to the earlier EU04 (also built by LEW), sharing the same traction engines, rectifiers, and gas compressors.
|
|
Some inward rectifiers, termed "weak inward rectifiers", carry measurable outward K+ currents at voltages positive to the K+ reversal potential (corresponding to, but larger than, the small currents above the 0 nA line in figure 1). They, along with the "leak" channels, establish the resting membrane potential of the cell. Other inwardly rectifying channels, termed "strong inward rectifiers," carry very little outward current at all, and are mainly active at voltages negative to the K+ reversal potential, where they carry inward current (the much larger currents below the 0 nA line in figure 1).Hille, p. 153.
|
|
Also, converting alternating to direct current using rectifiers (such as vacuum tubes or more recently via solid state technology) is effective and usually economical.
|
|
Mercury-arc rectifiers were installed in 1949 displacing the old rotary converters and steam plant, which were decommissioned prior to the end of the tramway.
|
|
A selenium rectifier has about the same size as copper-oxide rectifiers, but much larger than a silicon or germanium diode. Selenium rectifiers have a long but not indefinite service life of 60,000 to 100,000 hours, depending on rating and cooling. The rectifier can show some unforming of the rectifier characteristic after long storage.Ernst Bleule (ed.), Electronic methods, Academic Press, 1964, , pages 206–207.
|
|
Rectifiers have many uses, but are often found serving as components of DC power supplies and high-voltage direct current power transmission systems. Rectification may serve in roles other than to generate direct current for use as a source of power. As noted, detectors of radio signals serve as rectifiers. In gas heating systems flame rectification is used to detect presence of a flame.
|
|
Forty of these locomotives were built from 1961-64 by BR at Doncaster Works. The class were used to haul trains on the then newly electrified West Coast Main Line, from Birmingham, to , Manchester Piccadilly, Liverpool, and later . By 1965, electrification had spread south to London Euston. The locomotives of Class 85 were originally fitted with germanium rectifiers which were eventually replaced by silicon rectifiers.
|
|
Thermionic (vacuum-tube) diodes and solid-state (semiconductor) diodes were developed separately, at approximately the same time, in the early 1900s, as radio receiver detectors. Until the 1950s, vacuum diodes were used more frequently in radios because the early point-contact semiconductor diodes were less stable. In addition, most receiving sets had vacuum tubes for amplification that could easily have the thermionic diodes included in the tube (for example the 12SQ7 double diode triode), and vacuum-tube rectifiers and gas-filled rectifiers were capable of handling some high-voltage/high- current rectification tasks better than the semiconductor diodes (such as selenium rectifiers) that were available at that time.
|
|
Since momentary interruptions or reductions of output current may cause the cathode spot to extinguish, many rectifiers incorporate an additional electrode to maintain an arc whenever the plant is in use. Typically, a two or three phase supply of a few amperes passes through small excitation anodes. A magnetically shunted transformer of a few hundred VA rating is commonly used to provide this supply. This excitation or keep-alive circuit was necessary for single-phase rectifiers such as the excitron and for mercury-arc rectifiers used in the high-voltage supply of radiotelegraphy transmitters, as current flow was regularly interrupted every time the Morse key was released.
|
|
Anonas station is temporarily closed due to a fire which affected two rectifiers of the train line between Anonas and Katipunan stations on October 3, 2019.
|
|
Between 1971 and 1972, all ten locomotives were rebuilt with silicon rectifiers and dual brakes, and were reclassified under TOPS as Class 84, being renumbered 84001 - 84010.
|
|
Single-phase mercury-arc rectifiers were rarely used because the current dropped and the arc could be extinguished when the AC voltage changed polarity. The direct current produced by a single-phase rectifier thus contained a varying component (ripple) at twice the power supply frequency, which was undesirable in many applications for DC. The solution was to use two-, three-, or even six-phase AC power supplies so that the rectified current would maintain a more constant voltage level. Polyphase rectifiers also balanced the load on the supply system, which is desirable for reasons of system performance and economy. Most applications of mercury-arc valves for rectifiers used full-wave rectification with separate pairs of anodes for each phase.
|
|
Silicon controlled rectifiers (SCR's) are used to convert generated AC power to DC propulsive power. Two electric motor-driven bow thrusters are installed to enhance maneuvering and station-keeping.
|
|
Another early type of semiconductor device is the metal rectifier in which the semiconductor is copper oxide or selenium. Westinghouse Electric (1886) was a major manufacturer of these rectifiers.
|
|
The primary application of rectifiers is to derive DC power from an AC supply (AC to DC converter). Rectifiers are used inside the power supplies of virtually all electronic equipment. AC/DC power supplies may be broadly divided into linear power supplies and switched-mode power supplies. In such power supplies, the rectifier will be in series following the transformer, and be followed by a smoothing filter and possibly a voltage regulator.
|
|
A variety of silicon diodes of different current ratings. At left is a bridge rectifier. On the 3 center diodes, a painted band identifies the cathode terminal Silicon diodes are the most widely used rectifiers for lower voltages and powers, and have largely replaced other rectifiers. Due to their substantially lower forward voltage (0.3V versus 0.7V for silicon diodes) germanium diodes have an inherent advantage over silicon diodes in low voltage circuits.
|
|
In 1968 the first pole of the HVDC Vancouver Island link went into service. Its static inverters use mercury vapour rectifiers. Each of these rectifiers is 3.35 metres (11 ft) long, 1.22 metres (4 ft) wide and 6.10 metres (20 ft) high and has a weight of 4.5 metric tons. The valves are situated in a hall 26.21 metres (86 ft) long, 11.89 metres (39 ft) wide and 11.28 metres (37 ft) high.
|
|
It can be reduced by evenly spreading line frequency operated light sources across the three phases so that the illuminated area is lit from all three phases. This technique was applied successfully at the 2008 Beijing Olympics. Rectifiers may use a three-phase source to produce a six- pulse DC output. The output of such rectifiers is much smoother than rectified single phase and, unlike single-phase, does not drop to zero between pulses.
|
|
Non-linear loads like rectifiers produce current harmonics of the source frequency on the AC side and voltage harmonics of the source frequency on the DC side, due to switching behavior.
|
|
224x224px A selenium rectifier is a type of metal rectifier, invented in 1933. They were used in power supplies for electronic equipment and in high-current battery-charger applications until they were superseded by silicon diode rectifiers in the late 1960s. The arrival of the alternator in some automobiles was the result of compact, low-cost, high-current silicon rectifiers. These units were small enough to be inside the alternator case, unlike the selenium units that preceded silicon devices.
|
|
Selenium rectifiers had a shorter lifespan than desired. During catastrophic failure they produced significant quantities of malodorous and highly toxic fumes that let the repair technician know what the problem was. By far the most common failure mode was a progressive increase in forward resistance, increasing forward voltage drop and reducing the rectifier's efficiency. During the 1960s they began to be superseded by silicon rectifiers, which exhibited lower forward voltage drop, lower cost, and higher reliability.
|
|
Whereas normal semiconductor diodes have a roughly fixed voltage drop of around 0.5-1 volts, active rectifiers behave as resistances, and can have arbitrarily low voltage drop. Historically, vibrator driven switches or motor-driven commutators have also been used for mechanical rectifiers and synchronous rectification. Active rectification has many applications. It is frequently used for arrays of photovoltaic panels to avoid reverse current flow that can cause overheating with partial shading while giving minimum power loss.
|
|
Voltage-dependence may be regulated by external K+, by internal Mg2+, by internal ATP and/or by G-proteins. The P domains of IRK channels exhibit limited sequence similarity to those of the VIC family. Inward rectifiers play a role in setting cellular membrane potentials, and closing of these channels upon depolarization permits the occurrence of long duration action potentials with a plateau phase. Inward rectifiers lack the intrinsic voltage sensing helices found in many VIC family channels.
|
|
The company was established at the time of the economic boom in Massachusetts. Its first successful product was the gold bonded germanium diode, widely used in computers, military equipment, etc. After that the company manufactured silicon rectifiers (which David claims were the world first ones), grown junction silicon NPN transistors, silicon diodes, germanium diodes, silicon/germanium micro-diodes, silicon references, silicon regulators, silicon controlled rectifiers, bilateral switching diodes, etc. At its heyday Transitron employed 1,600 people.
|
|
Whereas normal semiconductor diodes have a roughly fixed voltage drop of around 0.5-1 volts, active rectifiers behave as resistances, and can have arbitrarily low voltage drop. Historically, vibrator driven switches or motor- driven commutators have also been used for mechanical rectifiers and synchronous rectification. Active rectification has many applications. It is frequently used for arrays of photovoltaic panels to avoid reverse current flow that can cause overheating with partial shading while giving minimum power loss.
|
|
Ion Channels of Excitable Membranes 3rd ed. (Sinauer: Sunderland, MA), p. 151. . Inward rectifiers also differ from tandem pore domain potassium channels, which are largely responsible for "leak" K+ currents.Hille, p. 155.
|
|
Danmarksplass The system is standard gauge with -wide cars, with the platforms built to allow long trams. The line has no terminal balloon loops, so trams must be bi-directional. The current is supplied from six rectifiers, specified so the system can operate with two rectifiers out of service. In the city center the overhead wire has been designed to minimize the number of poles, while in the suburban areas a conventional system has a carrier wire above the power wire.
|
|
A mechanical rectifier is a device for converting alternating current (AC) to direct current (DC) by means of mechanically operated switches. The best-known type is the commutator, which is an integral part of a DC dynamo, but before solid-state devices became available, independent mechanical rectifiers were used for certain applications. Before the invention of semiconductors, rectification at high currents involved serious losses. There were various vacuum/gas devices, such as the mercury arc rectifiers, thyratrons, ignitrons, and vacuum diodes.
|
|
Potassium delayed rectifiers have been implicated in many pharmacological uses in the investigation of biological toxins for drug development. A main component to many of the toxins with negative effects on delayed rectifiers contain cystine inhibitors that are arranged around disulfide bond formations. Many of these toxins originate from species of tarantulas. G. spatulata produces the hanatoxin, which was the first drug to be manipulated to interact with KCNB1 receptors by inhibiting the activation of most potassium voltage-gated channels.
|
|
The diode tube was a reliable alternative for detecting radio signals. As electronic engineering advanced, notably during World War II, this function of a diode came to be considered as one type of demodulation. While firmly established by history, the term "detector" is not of itself descriptive and should be considered outdated. Higher-power diode tubes or power rectifiers found their way into power supply applications until they were eventually replaced first by selenium, and later, by silicon rectifiers in the 1960s.
|
|
Thermionic diode rectifiers were widely used in power supplies in vacuum tube consumer electronic products, such as phonographs, radios, and televisions, for example the All American Five radio receiver, to provide the high DC plate voltage needed by other vacuum tubes. "Full-wave" versions with two separate plates were popular because they could be used with a center-tapped transformer to make a full-wave rectifier. Vacuum tube rectifiers were made for very high voltages, such as the high voltage power supply for the cathode ray tube of television receivers, and the kenotron used for power supply in X-ray equipment. However, compared to modern semiconductor diodes, vacuum tube rectifiers have high internal resistance due to space charge and therefore high voltage drops, causing high power dissipation and low efficiency.
|
|
J. H. Scaff, R. S. Ohl, "Development of Silicon Crystal Rectifiers for Microwave Radar Receivers", The Bell System Technical Journal, Vol. 24, No. 1, Jan. 1947. p. 1 Researchers at Bell Labs, Western Electric, MIT, Purdue and in the UK intensively developed point-contact diodes (crystal rectifiers or crystal diodes) during World War II for application in radar. After World War II, AT&T; used these in their microwave towers that criss-crossed the United States, and many radar sets use them even in the 21st century.
|
|
The shape of the anode arms ensures that any mercury that condenses on the glass walls drains back into the main pool quickly to avoid providing a conductive path between the cathode and respective anode. Glass envelope rectifiers can handle hundreds of kilowatts of direct-current power in a single unit. A six-phase rectifier rated 150 amperes has a glass envelope approximately 600 mm (24 inches) high by 300 mm (12 inches) outside diameter. These rectifiers will contain several kilograms of liquid mercury.
|
|
They had Four traction motors permanently coupled in parallel are fed by ignitron rectifiers. Speed control is by a tap changer on the input transformer. Mitsubishi transformer, 20 taps. Oerlikon exhauster and compressor, Arno rotary converter.
|
|
When an electric arc is established between the cathode pool and suspended anodes, a stream of electrons flows from the cathode to the anodes through the ionized mercury, but not the other way (in principle, this is a higher-power counterpart to flame rectification, which uses the same one-way current transmission properties of the plasma naturally present in a flame). These devices can be used at power levels of hundreds of kilowatts, and may be built to handle one to six phases of AC current. Mercury-arc rectifiers have been replaced by silicon semiconductor rectifiers and high-power thyristor circuits in the mid 1970s. The most powerful mercury- arc rectifiers ever built were installed in the Manitoba Hydro Nelson River Bipole HVDC project, with a combined rating of more than 1 GW and 450 kV.
|
|
The process is known as rectification, since it "straightens" the direction of current. Physically, rectifiers take a number of forms, including vacuum tube diodes, wet chemical cells, mercury-arc valves, stacks of copper and selenium oxide plates, semiconductor diodes, silicon-controlled rectifiers and other silicon-based semiconductor switches. Historically, even synchronous electromechanical switches and motors have been used. Early radio receivers, called crystal radios, used a "cat's whisker" of fine wire pressing on a crystal of galena (lead sulfide) to serve as a point-contact rectifier or "crystal detector".
|
|
Before the development of silicon semiconductor rectifiers, vacuum tube thermionic diodes and copper oxide- or selenium-based metal rectifier stacks were used. With the introduction of semiconductor electronics, vacuum tube rectifiers became obsolete, except for some enthusiasts of vacuum tube audio equipment. For power rectification from very low to very high current, semiconductor diodes of various types (junction diodes, Schottky diodes, etc.) are widely used. Other devices that have control electrodes as well as acting as unidirectional current valves are used where more than simple rectification is required—e.g.
|
|
Ignitrons were long used as high-current rectifiers in major industrial and utility installations where thousands of amperes of AC must be converted to DC, such as aluminum smelters. Ignitrons were used to control the current in electric welding machines. Large electric motors were also controlled by ignitrons used in gated fashion, in a manner similar to modern semiconductor devices such as silicon controlled rectifiers and triacs. Many electric locomotives used them in conjunction with transformers to convert high voltage AC from the overhead lines to relatively low voltage DC for the traction motors.
|
|
During the beginning of the 20th century, 25 Hz power was much more readily available from commercial electrical utilities. The vast majority of urban subway systems used 25 Hz power to supply their lineside rotary converters used to generate the DC voltage supplied to the trains. Since rotary converters work more efficiently with lower frequency supplies, 25 Hz was a common supply frequency for these machines. Rotary converters have been steadily replaced over the past 70 years with, at first, mercury arc rectifiers and more lately solid-state rectifiers.
|
|
Rectifier circuits may be single-phase or multi-phase. Most low power rectifiers for domestic equipment are single-phase, but three- phase rectification is very important for industrial applications and for the transmission of energy as DC (HVDC).
|
|
A related area of research is to develop smaller rectifiers, because a smaller device has a higher cutoff frequency. Research projects are attempting to develop a unimolecular rectifier, a single organic molecule that would function as a rectifier.
|
|
Gerald L. Pearson (March 31, 1905 - October 25, 1987) was a physicist whose work on silicon rectifiers at Bell Labs led to the invention of the solar cell. In 2008, he was inducted into the National Inventors Hall of Fame.
|
|
In 1974 Tallinn Electrotechnical plant manufactured experimental UVP-5 rectifying units. They featured tablet avalanche rectifiers (12th class) with natural air cooling. One of these units was mounted in ER9P-32304 motor car, which were in use by Gorky Railroad.
|
|
The invention of the p–n junction is usually attributed to American physicist Russell Ohl of Bell Laboratories in 1939. Two years later (1941), Vadim Lashkaryov reported discovery of p–n junctions in Cu2O and silver sulphide photocells and selenium rectifiers.
|
|
Copper-oxide rectifier Metal rectifiers consist of washer-like discs of different metals, either copper (with an oxide layer to provide the rectification) or steel or aluminium, plated with selenium. The discs are often separated by spacer sleeves to provide cooling.
|
|
It is caused by nonlinear loads represented for instance by semiconducting devices (rectifiers, thyristors) especially when used for rectification of an alternating current to a direct one. The rectification is needed especially for providing current for electric traction and electrochemical industry.
|
|
For a given load, sizing of a smoothing capacitor is a tradeoff between reducing ripple voltage and increasing ripple current. The peak current is set by the rate of rise of the supply voltage on the rising edge of the incoming sine- wave, reduced by the resistance of the transformer windings. High ripple currents increase I2R losses (in the form of heat) in the capacitor, rectifier and transformer windings, and may exceed the ampacity of the components or VA rating of the transformer. Vacuum tube rectifiers specify the maximum capacitance of the input capacitor, and SS diode rectifiers also have current limitations.
|
|
While being fitted with an updated propulsion system from General Electric, the Silverliner IVs were nevertheless still delivered with Ignitron tube rectifiers, which were later replaced with silicon controlled rectifiers. A readily apparent external feature of the Silverliner IV is a windowed body panel plug in the middle of the cars on each side, a provision for high-platform-only center doors which have never been installed, in contrast with New Jersey Transit's similar, contemporary Arrow II and III cars which were built with such doors. Internally, pairs of seats occupy this partitioned area which was intended for passenger flow.
|
|
As with the Class 84, the Class 83 suffered with problems due to the mercury-arc rectifiers. After spending several years in storage (1967 to 1971), they were rebuilt with silicon rectifiers, as were already fitted to E3100, and dual braking between July 1970 and October 1973. The decision to reinstate the fifteen engines of Class 83 was the result of the extension of the electrification from Weaver Junction to Glasgow, which required more electric locomotives. With both Class 83 and Class 84 being returned to traffic only thirty-six Class 87 were required to be built.
|
|
Solid-state technology was in its infancy, represented by copper oxide and selenium rectifiers. All of these gave excessive forward voltage drop at high currents. One answer was mechanically opening and closing contacts, if this could be done quickly and cleanly enough.
|
|
Cuynet, Jean (2005). La traction électrique en France 1900-2005. Paris: La Vie du Rail. The main reason why electrification at this voltage had not been used before was the lack of reliability of mercury-arc-type rectifiers that could fit on the train.
|
|
Robert Noel Hall (December 25, 1919 - November 7, 2016) was an American engineer and applied physicist. He demonstrated the first semiconductor laser and invented a type of magnetron commonly used in microwave ovens. He also contributed to the development of rectifiers for power transmission.
|
|
Because this was used in resistance welding there were two Ignatrons for the two phases of an AC circuit. Because of the mercury at the bottom of the tube they were extremely difficult to ship. These tubes were eventually replaced by SCRs (Silicon Controlled Rectifiers).
|
|
C.S. Reference Library volume 4B, International Textbook Company, Scranton PA 1908, section 53, page 34. the DC traction motors for trolleybuses, trams, and subways, and electroplating equipment. The mercury rectifier was used well into the 1970s, when it was finally replaced by semiconductor rectifiers.
|
|
Each locomotive weighed 84 tonnes. They used ignitrons as current rectifiers. After the graduator and the transformer, single phase current is rectified by eight ignitrons feeding series-wired electric motors. Smoothing chokes produced a "wavy" a current that was well accepted by the motors.
|
|
These locomotives were built by a consortium of Mitsubishi, Hitachi and Toshiba (The Japanese Group, as attested by a plaque fixed on their sides) as a second option to the Europeans WAM-1. They were delivered in 1960 and were a bit lower powered than the WAM1 but had similar Bo-Bo wheel arrangement (4 wheels per bogie) with four Mitsubishi DC traction motors connected to the wheels permanently in parallel through a WN geared drive. The WAM2 had Ignitron rectifiers just like the WAM1 but some were later were refitted with Excitron rectifiers. Some even had the Mitsubishi logo painted on their sides.
|
|
HVDC Pole 2 thyristor valve hall at Haywards in the New Zealand HVDC Inter- Island scheme A valve hall is a building which contains the valves of the static inverters of a high-voltage direct current plant. The valves consist of thyristors, or at older plants, mercury arc rectifiers. Mercury arc rectifiers are usually supported by insulators mounted on the floor, while thyristor valves may be either supported by insulators or hung from the roof of the valve hall. The latter required a stronger ceiling structure, however the hall and the static inverter can better survive earthquakes compared to valve structures standing on the floor.
|
|
These locomotives were built by a consortium of Mitsubishi, Hitachi and Toshiba (The Japanese Group, as attested by a plaque fixed on their sides) as a second option to the Europeans WAG-1. They were delivered in 1960 and were a bit lower powered than the WAM1 but had similar Bo-Bo wheel arrangement (4 wheels per bogie) with four Hitachi DC traction motors connected to the wheels permanently in parallel through a WN geared drive. The WAG-2 had Ignitron rectifiers just like the WAG-1 but some were later were refitted with Excitron rectifiers. Some even had the Mitsubishi logo painted on their sides.
|
|
In 1974, they became part of Westinghouse Davenset Rectifiers Ltd, owned by Westinghouse Brake and Signal Company Ltd and in 1986 the Leicester site was closed, with manufacturing transferring to Chippenham. At least one of the commercial vehicles and three of the cars have been preserved.
|
|
There is another designation system for professional tubes such as transmitter ones. The first element designates function. The next elements varies in interpretation. For ignitrons, rectifiers, and thyratrons, there is a digit, then hyphen, then the anode current in amperes, a slash, anode voltage in kV.
|
|
He also uses a wah pedal. He's used Marshall G100R CD, Diezel VH4 and Mesa Triple Rectifiers. He is also known for playing his see-through Fernandes Vertigo guitar that is filled with fake blood that he pours on himself, drinks or spits into the crowd while playing.
|
|
Shive held several patents including Selenium rectifier and method of making it, Directly heated thermocouple, Photoresistive translating device, Selenium rectifier including tellurium and method of making it, Apparatus for and method of treating selenium rectifiers, Semiconductor photoelectric device, Conditioning of semiconductor translators, Semiconductor amplifier, and Alternating gate current.
|
|
Although they were reasonably efficient in this application, (at least compared to vacuum-tube rectifiers), their internal resistance tended to increase as they aged. Apart from reducing the available high voltage, this tends to make them run hotter, producing an unpleasant smell as the selenium starts to evaporate.
|
|
Some preforms are also used in diodes, rectifiers, optoelectronic devices and components packaging.Solder Preforms . AMETEK.Inc. •Difference between soldering and brazing Soldering involves joining of materials with a filler metal that melts below ~450 °C. It generally requires a relatively fine and uniform surface finish between the faying surfaces.
|
|
Steeplecabs are almost only used for DC electrification, not AC. The first electric railways used DC supplies which could be fed directly to their traction motors, without needing much electrical equipment on board. AC electrification required either large frame-mounted motors, or rectifiers. AC locomotives thus used the boxcab or centercab layout, where their high bodywork provided space for the additional transformer, rectifiers and control equipment. A centercab, such as the PRR GG1, is similar to a steeplecab and has the same single central control cab with a view in both directions, but there is only vision to one side of the locomotive from each side of the cab, as the hoods are too high to see over.
|
|
After foundation in 1904 the company expanded in the next decade, establishing several new factories including ones for electrical cables, machine and tool making, and large scale machines. In 1914 the company began manufacturing motor vehicles, with an electric transmission system, to the design of Balachowsky & Caire. During World War I the factory was stripped of machines by occupying German forces. In the interwar period ACEC began to produce vacuum-based electronics, including mercury arc rectifiers – in 1929 mercury-arc rectifiers were installed on Bruxelles tram system replacing rotary converters. The company also produced a high-power test installation, capable of producing 2.5GW in short circuit, with currents and voltages of up to 267kA and 250kV.
|
|
Also along the line are two "cross-tie" substations at Ngauranga and Tawa, which provide a switching function but don't have transformers or rectifiers. Public road-rail crossings have warning lights and barriers, and some are now fitted with automatically locking pedestrian gates to prevent use while alarms are operating.
|
|
122-3 However, the higher voltages used in many AC electrification systems reduces transmission losses over longer distances, allowing for fewer substations or more powerful locomotives to be used. Also, the energy used to blow air to cool transformers, power electronics (including rectifiers), and other conversion hardware must be accounted for.
|
|
Powerex offers a broad line of products, including IGBT; MOSFET Modules; Intelligent Power Modules (IPM); DIP-IPM; Module Accessories (including Gate Drivers and DC-DC Converters); Discrete Thyristors/SCR (Silicon Controlled Rectifier); Discrete Rectifiers; Thyristor and Diode Modules; Fast Recovery and Three-Phase Diode Modules; Assemblies; IGBT Assemblies; and Custom Modules.
|
|
The electrical division produces power and distribution transformers, high voltage switching gear, low voltage control gear, flame proof switch gear, voltage regulators and rectifiers, plant communication, and fire alarm and detection systems. The switchgear and electrical systems group is located in Kolkata, while the transformer & switchgear unit is located in Chennai.
|
|
The first VL80s were characterised by their mercury arc rectifiers. Later, they were replaced with silicon ones, thus giving birth to the ВЛ80К (en: VL80K) series. The К stands for кремний, the Russian word for silicon. Between the years 1961 and 1973, a total of 695 VL80Ks had been produced.
|
|
High power audio amplifiers and rectifiers required larger envelopes to dissipate heat. Transmitting tubes could be much larger still. Heat escapes the device by black-body radiation from the anode (plate) as infrared radiation, and by convection of air over the tube envelope.RCA "Transmitting Tubes Manual" TT-5 1962, p.
|
|
Devices in the low 800s tend to be transmitter output types, those in the higher 800s are not vacuum tubes, but gas-filled rectifiers and thyratrons, and those in the 900s tend to be special-purpose and high-frequency devices. Use was not rigorously systematic: the 807 had variants 1624, 1625, and 807W.
|
|
This construction results in substantial saving in weight in traction equipment and gives better adhesion. These locomotives utilize silicon rectifiers for conversion of ac power into dc. The traction motors are force ventilated and are fully suspended type. These motors are permanently grouped in parallel and controlled by tap changer and field weakening.
|
|
These vacuum tubes are mainly used for guitar and hi-fi amplifiers. In technical terms, JJ produces triodes, beam tetrodes and power pentodes. Double diode vacuum tubes for full wave AC-to-DC rectifiers are also produced. JJ also produces electrolytic capacitors for higher voltage purposes, generally for use in audio amplifiers.
|
|
The pantograph is of TransTech design. The ABB main transformer has four secondary taps, switchable to supply 1360 V under all electrification supplies. There are two MITRAC TC 3360 DP V01 main converters, one per bogie, which convert the single phase input to a 2800 V intermediate DC link using IGBT based rectifiers.
|
|
Each unit has a 7,100 kVA traction transformer, model ONDTSE-10000/25-82UHL2. Each transformer has a high voltage winding and three traction windings. Each section also has three VIP-4000 rectifiers. Each is powered by its own traction winding and provides power to two parallel connected traction motors on a bogie.
|
|
While the majority of the piggybacks were produced in blonde tolex, there are a few examples of the brown tolex Bassman amplifiers. Accomplishments for the company's amplifier division during these years include the introduction of the stand-alone spring reverb unit in 1961, followed by incorporation of the reverb circuit within a combo-amp design with the 1963 Vibroverb. Other changes include the shift of the top-of-the-line model from the traditional Twin to include other models, like the Vibrasonic in early 1960, as well as the blonde Showman in 1961. Fender began using silicon rectifiers to reduce heat and voltage sag caused by tube rectifiers, and introduced an all-new, very complex Tremolo circuit (or, as it referred by Fender - "vibrato").
|
|
In the late '60s Jennings drifted into financial problems and the company experienced various owner changes. Quality control was also inconsistent. During the Vox brand's early '70s "Dallas Arbiter" period, the tube rectifiers of AC30s were replaced by silicon rectifiers, which became standard on later AC30TB models. In the late 1970s Vox also introduced a solid-state AC30 (AC30SS), which is the AC30 model that was used by Status Quo. A tube AC30TB with spring reverb feature was reintroduced in 1978. In spite of at least one AC30 production run titled "Limited Edition" of 100 units with starting serial number 0100 (1991) (no reverb), production of the AC30 has practically never ceased: Newer AC30s are reissues of the various top boost AC30/6 (AC30TB) models.
|
|
This AC motor system did not have the advantages of the traction control of the BB 12000 series and their DC motors with precise control from the ignitron phase control. It was found that although the AC motor system was initially simpler to build as it did not need rectifiers, it was not so well-suited to low speed and accelerating from frequent stops, and so ito was generally restricted to longer non-stop mainline services. Once silicon rectifiers became available to replace the ignitrons, as had been used on the last of the BB 12000, this became the dominant way to build all AC electric locomotives for decades. The bogie designs were taken from the , but shortened and simplified as the locomotives were of lower speed.
|
|
Although being fitted with an updated propulsion system from General Electric, the Silverliner IVs were nevertheless still delivered with Ignitron tube rectifiers (necessary to convert the overhead (catenary) wire high voltage AC to DC required to operate the traction motors) which were later replaced with silicon controlled rectifiers. A readily apparent external feature of the Silverliner IV is a windowed body panel plug in the middle of the cars on each side, a provision for high-platform-only center doors which have never been installed, in contrast with New Jersey Transit's similar, contemporary Arrow II and III cars which were built with such operating center doors. Internally, pairs of seats occupy this partitioned area which was intended for passenger flow.
|
|
Matrix converter is a device which converts AC input supply to the required variable AC supply as output without any intermediate conversion process whereas in case of Inverter which converts AC - DC - AC which takes more extra components as diode rectifiers, filters, charge-up circuit but not needed those in case of matrix converters.
|
|
These were series inductors that operated for most of the cycle with saturated cores. When the current decreased below that for saturation, their inductances reduced the current considerably. Contact switching was timed to occur while their cores were un-saturated. In the USA, similar rectifiers were made by the I-T-E circuit breaker company.
|
|
Vishay Intertechnology, Inc. is an American manufacturer of discrete semiconductors and passive electronic components founded by Polish-born businessman Felix Zandman. Vishay has manufacturing plants in Israel, Asia, Europe, and the Americas where it produces rectifiers, diodes, MOSFETs, optoelectronics, selected integrated circuits, resistors, capacitors, and inductors. Vishay Intertechnology revenues for 2018 were $3.035 billion.
|
|
Cord sets must be distinguished from AC adapters, where the connector also contains a transformer, and possibly rectifiers, filters and regulators. Unwary substitution of a standard mains-voltage connector for the power supply would result in application of full line voltage to the connected device, resulting in its destruction and possible fire or personal injury.
|
|
HVDC Mechanicville–Schenectady was the first experimental HVDC transmission line in the United States. Built in 1932, the circuit traversed from Mechanicville, New York to Schenectady, New York. The system used mercury arc rectifiers at a voltage of 20,000 volts and a rated power of 5 MW. The facility was dismantled after World War II.
|
|
During WW2 Lucas was engaged by Rover to work on the combustion and fuel systems for the Whittle jet engine project making the burners. This came about because of their experience of sheet metal manufacture and CAV for the pumps and injectors. In about 1957Lucas Industries Vintage Semiconductors they started a semiconductor manufacturing plant to make rectifiers and transistors.
|
|
Blalock, Thomas J., "The Frequency Changer Era: Interconnecting Systems of Varying Cycles ". The history of various frequencies and interconversion schemes in the US at the beginning of the 20th century. Also devices with mercury arc rectifiers or vacuum tubes were in use. With the advent of solid state electronics, it has become possible to build completely electronic frequency changers.
|
|
Quadracs are a special type of thyristor which combines a "diac" and a "triac" in a single package. The diac is the triggering device for the triac. Thyristors are four-layer (PNPN) semiconductor devices that act as switches, rectifiers or voltage regulators in a variety of applications. When triggered, thyristors turn on and become low-resistance current paths.
|
|
Partridge Wilson Engineering was a company established in Leicester, England in 1926. They initially made radios, and then battery chargers. In 1934 they began to build battery electric road vehicles, producing both cars and milk floats, which were marketed under the Wilson Electric marque. Vehicle production ceased in 1954, but they continued to make chargers and rectifiers.
|
|
Direct current power for the interurban trolleys on the Liberty Bell Line was produced (from AC power supplied by overhead lines from Allentown) by rotary converters at substations in Allentown, Summit Lawn,Coopersburg, Quakertown, Sellersville, Souderton (in the carbarn), Lansdale, and Washington Square. Unlike the notation in the "See Also" section below, LVT never used mercury arc rectifiers.
|
|
A later version using a crystal diode is still used in crystal radio sets today. The limited frequency response of the headset eliminates the RF component, making the low pass filter unnecessary. More sophisticated envelope detectors include the grid-leak detector, the plate detector, the infinite-impedance detector, transistor equivalents of them and precision rectifiers using operational amplifiers.
|
|
Since 1961, an alternative method, using thyristors, has been in use. Both silicon-controlled rectifiers (SCR) and TRIACs are members of the thyristor family. The term thyristor includes all the semiconductor devices, which show inherent ON-OFF behavior, as opposed to allowing gradual changes in conduction. All thyristors are regenerative switching devices, and they cannot operate in linear manner.
|
|
His technology employed semiconductor- controlled rectifiers, with a semiconductor oscillator, which provided pulses of electrical power to power the motor. It won the Queen's Award to Industry in April 1970, and the Queen's Awards for Export in April 1975. A new factory opened in June 1970 at Gateshead. It opened its first subsidiary in 1968 in Paris.
|
|
Saturable reactor amplifiers were used for control of power to industrial furnaces. Magnetic amplifiers as variable AC voltage controllers have been mostly replaced by silicon controlled rectifiers or TRIACs. Magnetic amplifiers are still used in some arc welders. Small magnetic amplifiers were used for radio tuning indicators, control of small motor and cooling fan speed, control of battery chargers.
|
|
The rectifier, auxiliary rectifiers, controllers and the error and diagnostic system is of the same type as used on the NSB Class 70 multiple units. Finse on the Bergen Line Each unit weighs . The body is long, wide and tall. The center distance between the bogies is and the center wheel distance in the bogies is .
|
|
In the 1920s, DC was derived using electronic valves (mercury arc rectifiers). In modern systems, high-voltage DC (HVDC) "back-to- back" stations are used instead of mechanical equipment to convert between different frequencies and phases of AC power and solid-state thyristor rectifier systems are used for conversion from AC power to DC traction power.
|
|
This construction results in substantial saving in weight in traction equipment and gives better adhesion. These locomotives utilise silicon rectifiers for conversion of ac power into dc. The traction motors are force ventilated and are fully suspended type. These motors are permanently grouped in parallel and speed control is obtained through HT tap changer and TM field weakening.
|
|
Lightning and sparks due to static electricity are natural examples of the electrical breakdown of air. Electrical breakdown is part of the normal operating mode of a number of electrical components, such as gas discharge lamps like fluorescent lights, and neon lights, zener diodes, avalanche diodes, IMPATT diodes, mercury-vapor rectifiers, thyratron, ignitron, and krytron tubes, and spark plugs.
|
|
4 on p. 412. He used chemical (electrolytic) rectifiers, which are denoted "Z" (Zellen, cells). In 1920, he generalized this idea to a cascaded voltage multiplier, and developed detection methods for charged particles (proportional counter, spark counter). In the 1930s, using an independently invented Greinacher-style multiplier to research atomic nuclei, British researchers discovered artificial radioactivity.
|
|
These rectifiers use thyristor control and also convert power back to alternating current during regenerative braking. The first two prototypes used the same NB-418K6 traction motors as the VL80 series. Production units use the NB-514 model. Improvements in the aerodynamics of the ventilation ducts reduced the number of cooling fans for this motor by half.
|
|
GD241 PNP transistor in a TO-66 package. TO-66 is a type of semiconductor package for devices with three pins, such as transistors. The shape is similar to the TO-3 package, but the size is smaller. The TO-66 package is made entirely of metal and is commonly used by silicon controlled rectifiers and power transistors.
|
|
It is a type of cold cathode gas-filled tube, but is unusual in that the cathode, instead of being solid, is made from a pool of liquid mercury and is therefore self-restoring. As a result, mercury-arc valves were much more rugged and long-lasting, and could carry much higher currents than most other types of gas discharge tube. Invented in 1902 by Peter Cooper Hewitt, mercury-arc rectifiers were used to provide power for industrial motors, electric railways, streetcars, and electric locomotives, as well as for radio transmitters and for high-voltage direct current (HVDC) power transmission. They were the primary method of high power rectification before the advent of semiconductor rectifiers, such as diodes, thyristors and gate turn-off thyristors (GTOs) in the 1970s.
|
|
He co-founded a company that worked on developing inert gas-glowing cathode rectifiers, and subsequently in the 1930s worked as an independent inventor for companies such as Osram and Philips. After World War II, He was invited by Engelhard Industries, Newark to continue his research. He and Hans Spanner were each awarded the Franklin Institute's Frank P. Brown Medal in 1954.
|
|
Each plate is able to withstand about 20 volts in the reverse direction. The metal squares, or disks, also serve as heat sinks in addition to providing a mounting place for the selenium disks. Plates can be stacked indefinitely to withstand higher voltages. Stacks of thousands of miniature selenium disks have been used as high-voltage rectifiers in television sets and photocopy machines.
|
|
Each cell can withstand a reverse voltage around 25 volts and has a forward voltage drop around 1 volt, which limits the efficiency at low voltages. Selenium rectifiers have an operating temperature limit of 130 °C and are not suitable for high-frequency circuits.H. P. Westman (ed), Reference Data for Radio Engineers Fifth Edition, Howard W. Sams & Co., Inc. 1968, chapter 13.
|
|
With the help of an Arts Council of England lottery grant the projection system was refurbished. Xenon arc bulbs replaced the carbon arcs and new rectifiers were fitted. A new sound system based around a Dolby CP500 processor was installed. This can play films with mono or Dolby Stereo analogue soundtracks as well as those with a 5.1 Dolby Digital soundtrack.
|
|
Feedback provides the position in space the car body occupies and what amount of actuator change needs to be applied to reach the next position and at what rate. Control also triggers various audio, receives location information from communications and adjusts power with Silicon Control Relays and Silicon Control Rectifiers to operate motors and switches, the most important switch being "STOP".
|
|
The ringleaders had to coordinate distillers, rectifiers, gaugers, storekeepers, revenue agents, and Treasury clerks by recruitment, impressment, and extortion.Rives 2000McFeely 1981, pp. 405–406 On January 26, 1875, Bristow ordered Internal Revenue officers in various sites to different locations, effective February 15, 1875, on a suggestion from Grant. This would keep the fraudulent officers off guard and allow investigators to uncover their misdeeds.
|
|
The direction of a wound field DC motor can be changed by reversing either the field or armature connections but not both. This is commonly done with a special set of contactors (direction contactors). The effective voltage can be varied by inserting a series resistor or by an electronically controlled switching device made of thyristors, transistors, or, formerly, mercury arc rectifiers.
|
|
The railcar bodies utilise a frameless construction similar to the ER2 series trainsets, with a number of modifications due to the different equipment arrangement, such as AC transformers and rectifiers. The car entrances are fitted for both high and low platforms. Like most Soviet rollingstock, the cars have SA-3 automatic couplers. The bodies are supported by two twin-axle bogies.
|
|
Brushless excitation has been historically lacking the fast flux de- regulation, which has been a major drawback. However, new solutions have emerged. Modern rotating circuitry incorporates active de-excitation components on the shaft, extending the passive diode bridge. Moreover, their recent developments in high-performance wireless communication have realized fully controlled topologies on the shaft, such as the thyristor rectifiers and chopper interfaces.
|
|
In 1967, one of the sets at Stella South became the world's first in commercial operation to use brushless excitation. The set was modified by Parsons to use A.C. exciters and silicon diode rectifiers. The stations' switchgear was manufactured by A. Reyrolle & Company. The power stations were illuminated by what was then the most powerful lighting installation in North East England.
|
|
Later versions had a calibrated, screw-in, fuse on the front panel. After copper oxide instrument rectifiers became available in the late 1920s, a 20-range "Universal" version of the AVOmeter was introduced in 1931 having both direct and alternating voltage current ranges.L. O. Grondahl and P. H. Geiger, A New Electronic Rectifier, A. 1. E. E. 46, 357-366 (1927).
|
|
These have not been retrofitted with air train brakes. Like the WAG-1 they were also used around the ER-SER-NER-NR circuit as it was the first AC electrified area and hauled ordinary passenger trains and freights only. They were also used double-headed for freight trains. They had Four traction motors permanently coupled in parallel are fed by ignitron rectifiers.
|
|
The two main types of potassium channels in cardiac cells are inward rectifiers and voltage-gated potassium channels. Inwardly rectifying potassium channels (Kir) favour the flow of K+ into the cell. This influx of potassium, however, is larger when the membrane potential is more negative than the equilibrium potential for K+ (~-90 mV). As the membrane potential becomes more positive (i.e.
|
|
The important components of diesel–electric propulsion are the diesel engine (also known as the prime mover), the main generator/alternator-rectifier, traction motors (usually with four or six axles), and a control system consisting of the engine governor and electrical or electronic components, including switchgear, rectifiers and other components, which control or modify the electrical supply to the traction motors. In the most elementary case, the generator may be directly connected to the motors with only very simple switchgear. Originally, the traction motors and generator were DC machines. Following the development of high-capacity silicon rectifiers in the 1960s, the DC generator was replaced by an alternator using a diode bridge to convert its output to DC. This advance greatly improved locomotive reliability and decreased generator maintenance costs by elimination of the commutator and brushes in the generator.
|
|
Other products, e.g. some kinds of silicon controlled rectifiers (SCRs) or power transistors were competitive with the world market and so TESLA was the supplier for all Eastern Europe countries. Some high quality products were even exported to western countries, for example, the turntables NC 470 or NC 500 under the tradename Lenco. In 1953, the production of the first Czechoslovak television Tesla 4001A began in Strašnice.
|
|
Since telephone exchanges use DC, the building's battery room is generally wired directly to the consuming equipment and floats continuously on the output of the rectifiers that normally supply DC rectified from utility power. When utility power fails, the battery carries the load without needing to switch. With this simple though somewhat expensive system, some exchanges have never lost power for a moment since the 1920s.
|
|
All of these devices function as rectifiers. it was expected that these high-power silicon "self- commutating switches", in particular IGBTs and a variant thyristor (related to the GTO) called the integrated gate-commutated thyristor (IGCT), would be scaled-up in power rating to the point that they would eventually replace simple thyristor-based AC rectification systems for the highest power- transmission DC applications.
|
|
Two locomotives had three two-axle trucks (E3b). The significant technical difference between the locomotives was that those from General Electric used traditional AC traction motors. Those by Westinghouse had mercury arc rectifiers to convert the AC traction power to DC. In consequence they were able to use ordinary DC traction motors, identical to those on contemporary diesel-electric locomotives. The locomotives were scrapped in 1964.
|
|
Again the suggestion to link the Lilleaker Line to the Ekeberg Line were launched. Oslo Sporveier calculated it would cost NOK 3.6 million for investments, including rebuilding 20 Gullfisk trams, new rectifiers and new tracks. This was less than the necessary 30 buses needed for conversion to bus services. The last of the older Ekeberg Line trams to Skøyen ran on 5 August 1973.
|
|
Battery constructed by Karol Pollak His numerous inventions also cover other areas, among them: electric motors, color printing device, and a type of microphone. His main activity was related to chemical sources of energy – galvanic cells and batteries. He obtained a patent for manufacturing lead-acid batteries. Design of full rectifier included in Karol Pollak patent He also has designed commutator and electrolytic rectifiers.
|
|
A unijunction transistor (UJT) is a three-lead electronic semiconductor device with only one junction that acts exclusively as an electrically controlled switch. The UJT is not used as a linear amplifier. It is used in free-running oscillators, synchronized or triggered oscillators, and pulse generation circuits at low to moderate frequencies (hundreds of kilohertz). It is widely used in the triggering circuits for silicon controlled rectifiers.
|
|
Power was collected from a diamond-shaped pantograph, and the control system consisted of a step-down transformer connected to an AC/DC rectifier powered by mercury arc ignitron tubes. The DC output was then fed into a camshaft motor controller which provided for smooth acceleration. No dynamic braking system was fitted. In 1961 the mercury arc tubes were replaced by silicon diode rectifiers.
|
|
Pickard, Greenleaf Whittier "Means for receiving intelligence communicated by electric waves" Issued: August 30, 1906 Other experimenters tried a variety of other minerals as detectors. Semiconductor principles were unknown to the developers of these early rectifiers. During the 1930s understanding of physics advanced and in the mid 1930s researchers at Bell Telephone Laboratories recognized the potential of the crystal detector for application in microwave technology.
|
|
The CJ has operated its entire metre-gauge network with 1500 volt DC since 4 October 1953. For this purpose, the overhead line voltage was increased from 1200 to 1500 volts DC. The converter plant in Tramelan was replaced by three rectifiers in Orange, Les Reussilles and Le Noirmont. The rolling stock was almost completely replaced by new vehicles. No changes were made to the existing locomotives.
|
|
Corroded thallium rod Thallium(I) sulfide's electrical conductivity changes with exposure to infrared light therefore making this compound useful in photoresistors. Thallium selenide has been used in a bolometer for infrared detection. Doping selenium semiconductors with thallium improves their performance, thus it is used in trace amounts in selenium rectifiers. Another application of thallium doping is the sodium iodide crystals in gamma radiation detection devices.
|
|
Active rectifiers also clearly still need the smoothing capacitors present in passive examples. Using active rectification to implement AC/DC conversion allows a design to undergo further improvements (with more complexity) to achieve an active power factor correction, which forces the current waveform of the AC source to follow the voltage waveform, eliminating reactive currents and allowing the total system to achieve greater efficiency.
|
|
From 1927 to 1928 Brattain worked for the National Bureau of Standards in Washington, D.C., where he helped to develop piezoelectric frequency standards. In August 1929 he joined Joseph A. Becker at Bell Telephone Laboratories as a research physicist. The two men worked on the heat-induced flow of charge carriers in copper oxide rectifiers. Brattain was able to attend a lecture by Arnold Sommerfeld.
|
|
The first patent for phase-fired controllers derives from 1912. However realization was first possible in the 1920s, when mercury-arc valve rectifiers with control grids became available. However, this method of voltage regulation was not common at the time, because of the limitations of mercury arc valves. It became widespread with the invention of solid-state thyristors at the end of the 1950s.
|
|
The Silverliner IVs have never been officially rebuilt, but there have been a number of modifications to the class. The propulsion system was initially upgraded from the original mercury arc–based Ignitron rectifiers to more reliable solid state silicon controlled rectifiers and later the main transformers had their coolant replaced with one that did not contain PCBs. As this change was carried out in the early 1990s, all of the 9000 series Reading cars and some of the Penn Central cars were renumbered into the series 400 through 460 to help keep track of which units had undergone the modification. When the Center City Commuter Connection opened in 1984, the Reading cars were converted to full train automatic door operation to take advantage of the high level platforms at the new Market East Station (now Jefferson Station) and others on the former PRR "side" of the system.
|
|
Around 1950, France began a program of electrification with 25 kV at the 'industrial' frequency of 50 Hz. An experimental program was begun with four similar locomotive designs, one from each maker of electrical equipment, to find the best system. Investigating the electrification of the Lille – Thionville line, the CC 14000 were part of an order for 85 electric locomotives in 1952, each using a different system: five BB 12000 in a mono-continuous format with ignitron rectifiers, fifteen BB 13000 with direct motors, twenty four-phase CC 14000 and sixty-five CC 14100 with single phase-continuous rotating units. The project was very successful, with 150 locomotives ordered in 1954 amongst the BB 12000, BB 13000, CC 14000 and CC 14100 series. The various locomotive types were used in experimenting with different ways of transforming current flowing from the traction network through transformers and rectifiers to the traction motors.
|
|
The signal may be amplified before detection. If not, a very low voltage drop diode or a diode biased with a fixed voltage must be used. When using a rectifier for demodulation the capacitor and load resistance must be carefully matched: too low a capacitance makes the high frequency carrier pass to the output, and too high makes the capacitor just charge and stay charged. Rectifiers supply polarised voltage for welding.
|
|
They showcased their Davenset fast charger at the 1948 Commercial Motor show. It used a selenium rectifier, came mounted on a wheeled chassis to make it easier to move around a garage, and could charge a starter battery in about an hour. They also exhibited a new pistol grip battery tester. The company became part of Westinghouse Brake and Signal Company Ltd in 1974, and traded as Westinghouse Davenset Rectifiers.
|
|
Dynamotors were provided in at Town Hall and Lang Park to supply direct current to customers. Alternating current was adopted as the new standard from 1930, although the first AC substation did not come into use until 1935. The AC system was not completed until c. 1958. No new DC customers were accepted after 1935, but the existing supply continued, albeit with mercury-arc rectifiers in later years, until 1985.
|
|
Traditionally, varistors were indeed constructed by connecting two rectifiers, such as the copper-oxide or germanium-oxide rectifier in antiparallel configuration. At low voltage the varistor has a high electrical resistance which decreases as the voltage is raised. Modern varistors are primarily based on sintered ceramic metal-oxide materials which exhibit directional behavior only on a microscopic scale. This type is commonly known as the metal-oxide varistor (MOV).
|
|
The AM1s were fitted with mercury arc rectifiers but one was later converted to a solid state rectifier as a test. The stock was maintained at Meols Cop works near Southport. The line was closed to passengers and the stock withdrawn in early 1966. Unlike classes AM2-AM11, which became TOPS Classes 302-311, class AM1 was withdrawn before it could take its place in the system as class 301.
|
|
Problems with the mercury-arc rectifiers plagued this class and in 1962 E3036 was returned to GEC, the builder of the electrical equipment, in an attempt to find a solution. Within a year, all ten were out of service for repair. The problems persisted and in 1967 they were once more placed into storage, using the former steam shed at Bury,Railway World December 1967, p. 554. along with Class AL3.
|
|
Corbyn was born on 26 May 1949"Government and Opposition roles" . UK Parliament. Retrieved on 23 September 2015. in Chippenham, Wiltshire, and lived until the age of seven in the nearby village of Kington St Michael. He is the youngest of the four sons of Naomi Loveday (née Josling; 1915–1987), a maths teacher, and David Benjamin Corbyn (1915–1986), an electrical engineer and expert in power rectifiers.
|
|
However, when the membrane potential is set positive to the channel's resting potential (e.g. +60 mV), these channels pass very little current. Simply put, this channel passes much more current in the inward direction than the outward one, at its operating voltage range. These channels are not perfect rectifiers, as they can pass some outward current in the voltage range up to about 30 mV above resting potential.
|
|
GE employed then-new ignitron rectifier technology, first used on the experimental Pennsylvania Railroad E2c and E3b locomotives. The rectifiers converted the overhead AC to DC. A transformer stepped the voltage down from 11 kV to feed the rectifier. The DC voltage from the rectifier was then smoothed by a reactor before it was passed on to the traction motors. There were six traction motors, one for each axle.
|
|
Martin used his Paul Reed Smith guitar for three-quarters of the recording; for the rest of the album he used a John 5 Telecaster. The guitars were played through Mesa Boogie and Dual Rectifiers heads connected to Marshall amplifiers. He used an Eventide H3000 Harmonizer effects pedal on nearly all the songs. Benji Madden played an Ernie Ball bass running through JCM heads connected to Marshall amplifiers.
|
|
Both types of rotating machine produce a rotating magnetic field that induces an alternating current in the coils in the stator. A generator uses a mechanical commutator, graphite brushes running on copper segments, to convert the AC produced into DC by switching the external connections at the shaft angle when the voltage would reverse. An alternator accomplishes the same goal using rectifiers that don’t wear down and require replacement.
|
|
Each bogie has three rectifiers, each connected to a transformer that is again connected to two inverters. The motors are three-phase asynchronous motors located in the bogie frame and equipped with regenerative brakes. There is also an auxiliary three-phase power supply which powers the compressor, pumps, ventilators and other auxiliary equipment, operated by four separate inverters. The controller is a 16-bit microprocessor that communicates using optical fibre cables.
|
|
Schematic of basic ac-to-dc power supply Rectifiers are constructed from diodes, where they are used to convert alternating current (AC) electricity into direct current (DC). Automotive alternators are a common example, where the diode, which rectifies the AC into DC, provides better performance than the commutator or earlier, dynamo. Similarly, diodes are also used in Cockcroft–Walton voltage multipliers to convert AC into higher DC voltages.
|
|
Obtaining a DC supply controlled by rectifiers requires an AC power source. Consequently, the existing auxiliary generator was converted to a three-phase alternator with automatic voltage regulator. This arrangement gives improved control of traction current over conventional rheostatic systems and gives fine control when starting a train. Normally the driver has to maintain tractive effort well below the rail adhesion limit to give himself time to respond to wheel slip.
|
|
Gas rectifiers, which predated vacuum tubes, such as the argon-filled General Electric "Tungar bulb" and the Cooper-Hewitt mercury- pool rectifier, also provided an influence. Irving Langmuir and G. S. Meikle of GE are usually cited as the first investigators to study controlled rectification in gas tubes, about 1914. The first commercial thyratrons appeared circa 1928. The term "thyristor" was derived from a combination of "thyratron" and "transistor".
|
|
While performing with Seventh Void, he could be seen using Mesa/Boogie dual rectifiers and Schecter Solo-6 guitars in either a black finish (seen in the music video for "Last Walk In The Light"), or Sunburst (seen in the music video for "Heaven is Gone"). In late 2012, Schecter announced an artist model based on his custom baritone he used near the end of his Type O Negative tenure.
|
|
A common variation of this circuit uses just the two transistors on one side of the load, similar to a class AB amplifier. Such a configuration is called a "half bridge". The half bridge is used in some switched-mode power supplies that use synchronous rectifiers and in switching amplifiers. The half-H bridge type is commonly abbreviated to "Half-H" to distinguish it from full ("Full-H") H bridges.
|
|
In an 'alternator', the AC current is generated in the stationary stator, and then is converted to DC by the rectifiers (diodes). Typical passenger vehicle and light truck alternators use Lundell or 'claw-pole' field construction. This uses a shaped iron core on the rotor to produce a multi-pole field from a single coil winding. The poles of the rotor look like fingers of two hands interlocked with each other.
|
|
This type of circuit usually has fairly limited frequency range. Since practical rectifiers have non-zero voltage drop, accuracy and sensitivity is poor at low AC voltage values.Stephen A. Dyer, Wiley Survey of Instrumentation and Measurement, John Wiley & Sons, 2004 , pp. 277–281 To measure resistance, switches arrange for a small battery within the instrument to pass a current through the device under test and the meter coil.
|
|
SEPTA GE Silverliner IV at Bryn Mawr, PA, interlockingThe Silverliner IVs have never been officially rebuilt, but there have been a number of modifications to the class. The propulsion system was initially upgraded from the original mercury arc–based Ignitron rectifiers to more reliable solid state silicon controlled rectifiers and later the main transformers had their coolant replaced with one that did not contain PCBs. As this change was carried out in the early 1990s, all of the 9000 series Reading cars and some of the Penn Central cars were renumbered into the series 400 through 460 to help keep track of which units had undergone the modification. When the Center City Commuter Connection opened in 1984, the Reading cars were converted to full train automatic door operation to take advantage of the high level platforms at the new Market East Station (now Jefferson Station) and others on the former PRR "side" of the system.
|
|
They remain so even after the trigger is removed, and until the current is reduced to a certain level (or until they are triggered off). Diacs are bi-directional diodes that switch AC voltages and trigger triacs or silicon-controlled rectifiers (SCRs). Except for a small leakage current, diacs do not conduct until the breakover voltage is reached. Triacs are three-terminal, silicon devices that function as two SCRs configured in an inverse, parallel arrangement.
|
|
At the time of their invention, asymmetrical conduction devices were known as rectifiers. In 1919, the year tetrodes were invented, William Henry Eccles coined the term diode from the Greek roots di (from δί), meaning 'two', and ode (from οδός), meaning 'path'. The word diode, however, as well as triode, tetrode, pentode, hexode, were already in use as terms of multiplex telegraphy.W. H. Preece, "Multiplex Telegraphy", The Telegraphic Journal and Electrical Review, Vol.
|
|
In 2012 it received permission from the government of Bangladesh to open a manufacturing unit in India. Rahimafrooz operates in three broad domains: automotive after market, power and energy, and retail chain. It sells tyres, batteries, lubricants, emergency power products, diesel as well as gas generators, lighting products, electrical accessories, solar systems, energy solutions using compressed natural gas, and power rectifiers. The Group also runs 'Agora' the first retail chain in Bangladesh.
|
|
Born 1 January 1895 into the family of Vladimir Vasilievich Shuleikin the technical director of a small chemical-dyeing factory, Vasily Vladimirovich Shuleikin graduated from the Moscow Lutheran Reformer School founded by Ivan Fidler in 1912. He went on to Bauman Moscow State Technical University where he studied mathematics, graduating in 1917. His first published research work dealt with rectifiers (November, 1916). After graduation he remained at Bauman and started teaching there in 1918.
|
|
Magnetoresistive insulators for contactless signal transmission between two electrically isolated parts of electrical circuits were first demonstrated in 1997 as an alternative to opto-isolators. A Wheatstone bridge of four identical GMR devices is insensitive to a uniform magnetic field and reacts only when the field directions are antiparallel in the neighboring arms of the bridge. Such devices were reported in 2003 and may be used as rectifiers with a linear frequency response.
|
|
This is of importance in practical power systems that contain non-linear loads such as rectifiers, some forms of electric lighting, electric arc furnaces, welding equipment, switched-mode power supplies, variable speed drives and other devices. Filters consisting of linear capacitors and inductors can prevent harmonic currents from entering the supplying system. To measure the real power or reactive power, a wattmeter designed to work properly with non-sinusoidal currents must be used.
|
|
The voltage distortion then can cause problems in all electrical equipment connected to that power source, including the UPS itself. It will also cause more power to be lost in the wiring supplying power to the UPS due to the spikes in current flow. This level of "noise" is measured as a percentage of "total harmonic distortion of the current" (THDI). Classic UPS rectifiers have a THDI level of around 25%–30%.
|
|
Uno Lamm developed a mercury valve with grading electrodes making them suitable for high voltage direct current power transmission. In 1933 selenium rectifiers were invented. Julius Edgar Lilienfeld proposed the concept of a field-effect transistor in 1926, but it was not possible to actually construct a working device at that time. In 1947, the bipolar point- contact transistor was invented by Walter H. Brattain and John Bardeen under the direction of William Shockley at Bell Labs.
|
|
In frequency converters this property makes it possible to perform regenerative braking. PWM rectifiers are also used in distributed power generation applications, such as micro turbines, fuel cells and windmills. The major advantage of using the pulse width modulation technique is the reduction of higher order harmonics. It also makes it possible to control the magnitude of the output voltage, and improve the power factor by forcing the switches to follow the input voltage waveform using a PLL loop.
|
|
In an electric power system, a harmonic is a voltage or current at a multiple of the fundamental frequency of the system, produced by the action of non- linear loads such as rectifiers, discharge lighting, or saturated magnetic devices. Harmonic frequencies in the power grid are a frequent cause of power quality problems. Harmonics in power systems result in increased heating in the equipment and conductors, misfiring in variable speed drives, and torque pulsations in motors.
|
|
Power initially flows through the main breakers into an RF mains filter that prevents the flow of noise back onto the incoming power line. Then, rectifiers and capacitors charge and discharge to invert the negative half of the AC cycle and convert the line to positive DC voltage. This is called the DC intermediate. In the second stage, a buck converter draws from the DC intermediate and regulates current to the final power electronics via an electronic control board.
|
|
Herbert Mataré in 1950. He independently invented a point-contact transistor in June 1948. In 1948, the point-contact transistor was independently invented by German physicists Herbert Mataré and Heinrich Welker while working at the Compagnie des Freins et Signaux, a Westinghouse subsidiary located in Paris. Mataré had previous experience in developing crystal rectifiers from silicon and germanium in the German radar effort during World War II. Using this knowledge, he began researching the phenomenon of "interference" in 1947.
|
|
Special types of single-phase mercury-arc rectifiers are the Ignitron and the . The Excitron is similar to other types of valve described above but depends critically on the existence of an excitation anode to maintain an arc discharge during the half-cycle when the valve is not conducting current. The Ignitron dispenses with excitation anodes by igniting the arc each time conduction is required to start. In this way, ignitrons also avoid the need for control grids.
|
|
P8000 running WEGA 3.1 EAM manufactured measuring instruments, rectifiers, relays, circuit breakers, vacuum switches, instrumentation and control engineering, electric meters, radios, and computers. EAW was the manufacturer of power system distance protection equipment in East Germany. The last consumer products were the EAW AUDIO 145 stereo radio cassette recorder, the SKR 701 stereo cassette recorder, and the P8000 16-bit microcomputer, based on the East German U8000 clone of the Zilog Z8000, running a Unix clone called WEGA.
|
|
A major area of research is to develop higher frequency rectifiers, that can rectify into terahertz and light frequencies. These devices are used in optical heterodyne detection, which has myriad applications in optical fiber communication and atomic clocks. Another prospective application for such devices is to directly rectify light waves picked up by tiny antennas, called nantennas, to produce DC electric power. It is thought that arrays of antennas could be a more efficient means of producing solar power than solar cells.
|
|
The IGBTs are controlled by software in the DSP to draw current from the single-phase line in a sinusoidal fashion, charging capacitors on a constant-voltage DC bus. Because the incoming current is sinusoidal, there are no significant harmonics generated back onto the line as there are with the rectifiers found in most VFDs. The controlled rectifier input allows power factor correction. The output inverter consists of IGBTs that draw on the power of the DC bus to create an AC voltage.
|
|
A direct-current power source (generator or rectifier) having drooping characteristics and open circuit voltage of 70 volts or above is suitable for plasma arc welding. Rectifiers are generally preferred over DC generators. Working with helium as an inert gas needs open circuit voltage above 70 volts. This higher voltage can be obtained by series operation of two power sources; or the arc can be initiated with argon at normal open-circuit voltage and then helium can be switched on.
|
|
In December 2010, AERO Specialties acquired Australia-based JetGo International, a diesel-electric hybrid GPU manufacturer. JetGo is now manufactured and sold under the AERO brand. In 2016, AERO Specialties released a line of portable DC GPUs in collaboration with Powervamp, as well as becoming the company's exclusive distributor in North America. In 2017 AERO Specialties released into the US market, Powervamp's 400 Hz AC solid-state aircraft rectifiers and frequency converters branded with AERO Specialties orange and blue colours.
|
|
The Santolan Depot, where the trains of the line are cleaned and maintained, is also near the station, as well as the line's Operations Control Center (OCC), all are located in Pasig. This is the only station on this line with an island platform. Santolan station is temporarily closed due to a fire which affected two rectifiers of the train line one being between Katipunan and Anonas stations while the other was in the Santolan Depot on October 3, 2019.
|
|
Ripple (specifically ripple voltage) in electronics is the residual periodic variation of the DC voltage within a power supply which has been derived from an alternating current (AC) source. This ripple is due to incomplete suppression of the alternating waveform after rectification. Ripple voltage originates as the output of a rectifier or from generation and commutation of DC power. Ripple (specifically ripple current or surge current) may also refer to the pulsed current consumption of non-linear devices like capacitor-input rectifiers.
|
|
The farm estate and stock were auctioned off on 25 March 1957 at which time there were 100 head of dairy shorthorns, pigs, sheep and poultry. As a relief from the demanding manual labour required of physically able inmates, patients were allowed a wide range of social and leisure activities including sports, dances and fetes. The Main Hall provided a focus for these activities, having a proscenium stage, orchestra pit and two Gaumont-Kazee cinema projectors with Rank audio visual rectifiers.
|
|
This complicates the design of multistage amplifiers when compared with electronic devices. Magnetic amplifier output waveform (violet) at about 50% saturation. Input (yellow) is 120 VAC 60 Hz. Magnetic amplifier output waveform frequency spectrumMagnetic amplifiers introduce substantial harmonic distortion to the output waveform consisting entirely of the odd harmonics. Unlike the silicon controlled rectifiers or TRIACs which replaced them, the magnitude of these harmonics decreases rapidly with frequency so interference with nearby electronic devices such as radio receivers is uncommon.
|
|
Unlike other monopolar HVDC schemes, Swepol uses a metallic return consisting of 2 cables with sections for the submarine portion of the line, and a single cable with sections for the land portions. Both stations use air- core inductance smoothing rectifiers of 225 mH and a weight of 27.5 tonnes, with filters for the 11th, 13th, 24th, and 36th harmonics. Each filter consists of a coil and a capacitor switched in row. The filters for the 11th and 13th harmonics are adjustable.
|
|
Various numeral-only systems exist. These tend to be used for devices used in commercial or industrial equipment. The oldest numbering systems date back to the early 1920s, such as a two-digit numbering system, starting with the UV-201A, which was considered as "type 01", and extended almost continuously up into the 1980s. Three- and four-digit numeral-only systems were maintained by R.C.A., but also adopted by many other manufacturers, and typically encompassed rectifiers and radio transmitter output devices.
|
|
Non-welded contact construction utilizes the Schottky barrier principle. The metal side is the pointed end of a small diameter wire that is in contact with the semiconductor crystal.H. C. Torrey, C. A. Whitmer, Crystal Rectifiers, New York: McGraw-Hill, 1948 In the welded contact type, a small P region is formed in the otherwise N-type crystal around the metal point during manufacture by momentarily passing a relatively large current through the device.H. Q. North, Asymmetrically Conductive Device, U.S. patent 2,704,818U.
|
|
Voltage-gated potassium (Kv) channels represent the most complex class of voltage-gated ion channels from both functional and structural standpoints. Delayed rectifier potassium channels’ most prevalent role is in the falling phase of physiological action potentials. KCNB1 rectifiers are also important in forming the cardiac beat and rate synchronicity that exists within the heart, and the lysis of target molecules in the immune response. These channels can also act as effectors in downstream signaling in G-protein coupled receptor transduction.
|
|
The technology of rotary converters was replaced in the early 20th century by mercury-vapor rectifiers, which were smaller, did not produce vibration and noise, and required less maintenance. The same conversion tasks are now performed by solid state power semiconductor devices. Rotary converters remained in use in the West Side IRT subway in Manhattan into the late 1960s, and possibly some years later. They were powered by 25 Hz AC, and provided DC at 600 volts for the trains.
|
|
Tubes intended for series-string operation of the heaters across the supply have a specified controlled warm-up time to avoid excess voltage on some heaters as others warm up. Directly heated filament- type cathodes as used in battery-operated tubes or some rectifiers may fail if the filament sags, causing internal arcing. Excess heater-to-cathode voltage in indirectly heated cathodes can break down the insulation between elements and destroy the heater. Arcing between tube elements can destroy the tube.
|
|
Mercury compounds are toxic, highly persistent in the environment, and present a danger to humans and the environment. The use of large quantities of mercury in fragile glass envelopes presents a hazard of potential release of mercury to the environment should the glass bulb be broken. Some HVDC converter stations have required extensive clean-up to eliminate traces of mercury emitted from the station over its service life. Steel tank rectifiers frequently required vacuum pumps, which continually emitted small amounts of mercury vapor.
|
|
Oscillator/transformer systems are employed to reduce the voltages, then rectifiers are used to transform the AC power back to direct current. English physicist H. G. J. Moseley constructed the first of these. Moseley’s apparatus consisted of a glass globe silvered on the inside with a radium emitter mounted on the tip of a wire at the center. The charged particles from the radium created a flow of electricity as they moved quickly from the radium to the inside surface of the sphere.
|
|
The frequency range of interest spans from 150 kHz to 30 MHz for conducted emissions and from 30 MHz to 40 GHz for radiated emissions. Meeting these requirements and guaranteeing the functionality of an electrical apparatus subject to electromagnetic interference are the main reason to include an EMI filter. In an electrical system, power converters, i.e. DC/DC converters, inverters and rectifiers, are the major sources of conducted EMI, due to their high-frequency switching ratio which gives rise to unwanted fast current and voltage transients.
|
|
They consisted of pointed tungsten wire (in the shape of a cat's whisker) whose tip or point was pressed against the surface of a galena (lead sulfide) crystal. The first large area rectifier appeared around 1926 which consisted of a copper(I) oxide semiconductor thermally grown on a copper substrate. Subsequently, selenium films were evaporated onto large metal substrates to form the rectifying diodes. These selenium rectifiers were used (and are still used) to convert alternating current to direct current in electrical power applications.
|
|
Typical structure of a selenium rectifier Selenium rectifiers are made from stacks of aluminum or steel plates coated with about 1 μm of bismuth or nickel. A much thicker layer of selenium (50 to 60 μm) doped with a halogen is deposited on top of the thin metal plating. The selenium is then converted into polycrystalline gray (hexagonal) form by annealing. Cadmium selenide forms by reaction of the selenium with the tin- cadmium alloy and the CdSe-Se heterojunction is the active rectifying junction.
|
|
Typically these rectifiers were made up of stacks of metal plates or washers, held together by a central bolt, with the number of stacks determined by voltage; each cell was rated for about 20 V. An automotive battery charger rectifier might have only one cell: the high-voltage power supply for a vacuum tube might have dozens of stacked plates. Current density in an air-cooled selenium stack was about 600 mA per square inch of active area (about 90 mA per square centimeter).
|
|
Seven traction substations along the line take electricity from Wellington Electricity's 11,000-volt distribution network and transform and rectify it to 1500-volt direct current for the overhead traction lines. The substations are located at Wellington, Kaiwharawhara, Petone, Woburn, Pomare, Silverstream, and Upper Hutt. There is also some supply from the Lower Hutt traction sub- station on the Melling line. Also along the line are three "cross-tie" substations at Rocky Point, Epuni, and Heretaunga, which provide a switching function but don't have transformers or rectifiers.
|
|
With this gearing a maximum speed of was possible, although the standard operating speed on the BM&LP; was . Thyristor rectifiers step down the high-voltage AC to provide DC power at a much lower voltage to six GE780 traction motors, one per axle. The locomotive is rated at , with a starting tractive effort of and a continuous tractive effort of . Physically the locomotive is long and weighs , including some of ballast. GE made a number of changes when it redesigned the E60C for passenger use.
|
|
Ignitron rectifiers powering industrial process, 1945 An ignitron is usually a large steel container with a pool of mercury in the bottom that acts as a cathode during operation. A large graphite or refractory metal cylinder, held above the pool by an insulated electrical connection, serves as the anode. An igniting electrode (called the ignitor), made of a refractory semiconductor material such as silicon carbide, Turner pg. 7-182 is briefly pulsed with a high current to create a puff of electrically conductive mercury plasma.
|
|
This practice ended when the musical A Chorus Line introduced computerized lighting control and thyristor (SCR) dimmers to Broadway, and New York theaters were finally converted to AC. In January 1998, Consolidated Edison started to eliminate DC service. At that time there were 4,600 DC customers. By 2006, there were only 60 customers using DC service, and on November 14, 2007, the last direct-current distribution by Con Edison was shut down. Customers still using DC were provided with on-site AC to DC rectifiers.
|
|
The most common function of a diode is to allow an electric current to pass in one direction (called the diode's forward direction), while blocking it in the opposite direction (the reverse direction). As such, the diode can be viewed as an electronic version of a check valve. This unidirectional behavior is called rectification, and is used to convert alternating current (ac) to direct current (dc). Forms of rectifiers, diodes can be used for such tasks as extracting modulation from radio signals in radio receivers.
|
|
Other toxins, such as stromatoxin, heteroscordratoxin, and guangxitoxin, target the selectivity of voltage KCNB1 rectifiers, by either lowering potassium binding affinity or increasing the binding rate of potassium. This can lead to excitotoxicity, or overstimulation of postsynaptic neurons. In nature, the prey of tarantula that are injected with these endogenous toxins induces this excitotoxic effect, producing paralysis for easy capture. Physiologically, these venoms work on KCNB1 rectifier affinity by altering the channels’ voltage sensor, making it more or less sensitive to extracellular potassium concentrations.
|
|
Horiba, who was in his second year at Kyoto University, left the university in 1945 to start his own business, Horiba Radio Laboratory (HRL). In addition to producing electronic parts and repairing electronic instruments, they reconditioned batteries. The power distribution system after the war was unreliable, so there was a strong demand for storage batteries for electric lights that could be used in the case of blackouts. Horiba acquired discarded storage batteries and selenium rectifiers which the company Nihon Denchi had produced for wartime use.
|
|
In electronic signal processing, a square law detector is a device that produces an output proportional to the square of some input.IEEE Std. 100 Authoritative Dictionary of Standards Terms Seventh Edition, IEEE, 2000, ,Square law detection For example, in demodulating radio signals, a semiconductor diode can be used as a square law detector, providing an output current proportional to the square of the amplitude of the input voltage over some range of input amplitudes.H. C. Torrey, C. A. Whitmer, Crystal Rectifiers, New York: McGraw-Hill, 1948, pp.
|
|
Alternator (silver) mounted on a V8 engine An alternator is a type of electric generator used in modern automobiles to charge the battery and to power the electrical system when its engine is running. Until the 1960s, automobiles used DC dynamo generators with commutators. With the availability of affordable silicon diode rectifiers, alternators were used instead. This was encouraged by the increasing electrical power required for cars in this period, with increasing loads from larger headlamps, electric wipers, heated rear windows and other accessories.
|
|
The capabilities and economy of power electronics system are determined by the active devices that are available. Their characteristics and limitations are a key element in the design of power electronics systems. Formerly, the mercury arc valve, the high-vacuum and gas-filled diode thermionic rectifiers, and triggered devices such as the thyratron and ignitron were widely used in power electronics. As the ratings of solid-state devices improved in both voltage and current-handling capacity, vacuum devices have been nearly entirely replaced by solid-state devices.
|
|
For alternating current electric power, the universal practice is to specify RMS values of a sinusoidal waveform. One property of root mean square voltages and currents is that they produce the same heating effect as a direct current in a given resistance. The peak-to-peak value is used, for example, when choosing rectifiers for power supplies, or when estimating the maximum voltage that insulation must withstand. Some common voltmeters are calibrated for RMS amplitude, but respond to the average value of a rectified waveform.
|
|
Because of the costs of larger equipment and wasted energy, electrical utilities will usually charge a higher cost to industrial or commercial customers where there is a low power factor. Power-factor correction increases the power factor of a load, improving efficiency for the distribution system to which it is attached. Linear loads with low power factor (such as induction motors) can be corrected with a passive network of capacitors or inductors. Non-linear loads, such as rectifiers, distort the current drawn from the system.
|
|
Protective plastic coatings and cable jackets can rapidly deteriorate from leaking steam pipes present in many urban areas and from gasoline leaking from underground storage tanks. The most aggressive contributor to corrosion of underground plant is dc stray current from electrified rail transportation systems, cathodic protection rectifiers, or welding and mining operations. Although such dc currents are mostly dealt with “after the fact” using protective systems (e.g., low resistance bonds, reverse current switches, cathodic protection), some of the protection has to be included at the manufacturing stage.
|
|
From there it took another 18 months of getting everything else assembled and hooked up. The 20 kV transformer needed for running the coils was made by Cooper electronics and the switching mechanism that to switch it all on was supplied by G&W.; Quad- Plus was brought in to commission the rectifiers which allows the field shaping of the device. In this time water cooling tanks were brought in and installed and the universities pipe fitters built the cooling system for the machine and installed the water pump.
|
|
In 1968 and as a part of the small team to do so, he moved to Hyderabad from BARC to set up the Electronics Corporation of India. After a short stint, he found the place difficult and went to start a semiconductor activity of his own in Dharwar manufacturing Silicon Controlled Rectifiers. The effort did not succeed and he found limitations in both the fields, technical and commercial. Dharwar exposed Rao to diverse fields of knowledge and enabled him to form a friendship with literature enthusiasts and writers.
|
|
In 1946, acting on a suggestion by Shockley he put a voltage on a droplet of glycol borate (gu) placed across a P-N junction producing the first evidence of power amplification in the search for the transistor. In 1954 his work on silicon rectifiers led to the first practical photovoltaic cell (solar cell), together with Daryl Chapin and Calvin Souther Fuller. He took early retirement from Bell in 1960 to take up the position of Professor of Electrical Engineering at Stanford setting up a research program on compound semiconductors.
|
|
Electrolytic rectifiers most commonly used an aluminum anode and a lead or steel cathode, suspended in a solution of tri-ammonium ortho- phosphate. The rectification action is due to a thin coating of aluminum hydroxide on the aluminum electrode, formed by first applying a strong current to the cell to build up the coating. The rectification process is temperature- sensitive, and for best efficiency should not operate above 86 °F (30 °C). There is also a breakdown voltage where the coating is penetrated and the cell is short-circuited.
|
|
Eventually, steam heat vans were transferred from the North Island Night Limited when the Silver Star was delivered a year late in November 1971. The DJ class were the first locomotives in New Zealand to employ an AC/DC transmission, all previous diesel locomotive types had DC/DC transmissions. AC current was rectified to DC using silicon rectifiers feeding the traction motors. They were also turbocharged with a rating, but were only safe for five minutes an hour at that rating, with operation at for an hour on, and for the next hour.
|
|
Molecular rectifiers are mimics of their bulk counterparts and have an asymmetric construction so that the molecule can accept electrons in one end but not the other. The molecules have an electron donor (D) in one end and an electron acceptor (A) in the other. This way, the unstable state D+ – A− will be more readily made than D− – A+. The result is that an electric current can be drawn through the molecule if the electrons are added through the acceptor end, but less easily if the reverse is attempted.
|
|
Many black-and-white and color television receivers were built using All American Five principles, including a hot chassis and series-wired heaters. The designs were found primarily in portable or inexpensive sets ranging from the 1950s to even as late as the GE Portacolor series which was finally discontinued in the 1980s. Early sets tended to use selenium rectifiers in place of a tube; later sets used silicon diodes. Some of these sets were hybrid, using transistors for small signal applications and vacuum tubes in place of then-expensive power transistors.
|
|
That is, it permits normal functioning of DC-powered equipment when batteries have been installed backwards, or when the leads (wires) from a DC power source have been reversed, and protects the equipment from potential damage caused by reverse polarity. Alternatives to the diode-bridge full-wave rectifiers are the center-tapped transformer and double-diode rectifier, and voltage doubler rectifier using two diodes and two capacitors in a bridge topology. half-wave and full-wave rectified signals"Rectifier", Concise Encyclopedia of Science and Technology, Third Edition, Sybil P. Parker, ed. McGraw-Hill, Inc.
|
|
They introduced some new features; the first standard multiple units with disc brakes (emergency stop from top speed in 33 seconds over ); the first naturally air-cooled rectifiers (silicon diodes on cups of beryllium oxide), inductors and transformers. Noise was reduced by sprayed asbestos on the floor, body and roof. Original livery was overall Rail Blue, later amended to the standard BR blue and grey colour scheme. Initially they were primarily used on local services from London Euston to Bletchley, Milton Keynes, Northampton and Birmingham New Street, and within the West Midlands.
|
|
Animation showing operation of a brushed DC electric motor. An electric motor is an electrical machine that converts electrical energy into mechanical energy. Most electric motors operate through the interaction between the motor's magnetic field and electric current in a wire winding to generate force in the form of torque applied on the motor's shaft. Electric motors can be powered by direct current (DC) sources, such as from batteries, motor vehicles or rectifiers, or by alternating current (AC) sources, such as a power grid, inverters or electrical generators.
|
|
Leakage channels are the simplest type of ion channel, in that their permeability is more or less constant. The types of leakage channels that have the greatest significance in neurons are potassium and chloride channels. Even these are not perfectly constant in their properties: First, most of them are voltage-dependent in the sense that they conduct better in one direction than the other (in other words, they are rectifiers); second, some of them are capable of being shut off by chemical ligands even though they do not require ligands in order to operate.
|
|
Solid state soft starters can control one or more phases of the voltage applied to the induction motor with the best results achieved by three-phase control. Soft starters controlled via two phases have the disadvantage that the uncontrolled phase will always shows some current unbalance with respect to the controlled phases.Typically, the voltage is controlled by reverse-parallel-connected silicon-controlled rectifiers (thyristors), but in some circumstances with three-phase control, the control elements can be a reverse-parallel-connected SCR and diode. Another way to limit motor starting current is a series reactor.
|
|
They were based on ASEA's Rb design for Swedish Railways. The first fifteen locomotives were delivered to TCDD in 1998, followed by five more in 1999 and two in 2004 and 2005 respectively. They have been modernised by having the diodes replaced with thyristor rectifiers, making them similar to the Rc, the thyristor-based successor to the Rb. Two units were scrapped after the Tavşancıl accident in 2004. The two replacement units delivered in 2004-05 have higher top speeds that the other units, who could only run at 140 km/h.
|
|
Unijunction transistor circuits were popular in hobbyist electronics circuits in the 1960s and 1970s because they allowed simple oscillators to be built using just one active device. For example, they were used for relaxation oscillators in variable-rate strobe lights. Later, as integrated circuits became more popular, oscillators such as the 555 timer IC became more commonly used. In addition to its use as the active device in relaxation oscillators, one of the most important applications of UJTs or PUTs is to trigger thyristors (silicon controlled rectifiers (SCR), TRIAC, etc.).
|
|
At NAMM 2014 ESP announced the release of Weinman's first signature guitar, the BW-1, which is based on the company's PS-1 "Xtone" model. He is also known for frequently playing the ESP H and MH series. Weinman has been seen using a variety of amps in the studio, ranging from a Bogner Uberschall, a Laney GH50L and a Marshall JCM, but he mainly uses Mesa/Boogie Triple Rectifiers and a Mark V for live performances. In addition to playing guitar, Weinman occasionally plays a Fender Precision Bass in live performances with The Prodigy.
|
|
A static transfer switch uses power semiconductors such as Silicon-controlled rectifiers (SCRs) to transfer a load between two sources. Because there are no mechanical moving parts, the transfer can be completed rapidly, perhaps within a quarter-cycle of the power frequency. Static transfer switches can be used where reliable and independent sources of power are available, and it is necessary to protect the load from even a few power frequency cycles interruption time, or from any surges or sags in the prime power source.Roger C. Dugan et al.
|
|
Instead it was used as a test bed with silicon rectifiers and transductors, this being the first step towards thyristor control. It became a Type A, geared for passenger trains, and numbered E3100. The other two Type B locomotives were eventually rebuilt as Type A, being renumbered E3098 (ex E3303) and E3099 (ex E3304). Power was provided by overhead catenary energized at 25,000 V AC. Under the pre-TOPS British Rail classification, the first fourteen locomotives, E3025 - E3035 and E3303, E3304 (later E3098 and E3099) were Class AL3 (meaning the 3rd design of AC Locomotive).
|
|
It is also possible to replace the standard diode-bridge rectifier with a bi-directional IGBT switching device bridge mirroring the standard inverter which uses IGBT switching device output to the motor. Such rectifiers are referred to by various designations including active infeed converter (AIC), active rectifier, IGBT supply unit (ISU), active front end (AFE), or four-quadrant operation. With PWM control and a suitable input reactor, an AFE's AC line current waveform can be nearly sinusoidal. AFE inherently regenerates energy in four-quadrant mode from the DC side to the AC grid.
|
|
A TRIAC (triode for alternating current; also bidirectional triode thyristor or bilateral triode thyristor) is a three terminal electronic component that conducts current in either direction when triggered. The term TRIAC is a genericised trademark. TRIACs are a subset of thyristors (analogous to a relay in that a small voltage induced current can control a much larger voltage and current) and are related to silicon controlled rectifiers (SCRs). TRIACs differ from SCRs in that they allow current flow in both directions, whereas an SCR can only conduct current in a single direction.
|
|
The work function from a thorium surface is lowered possibly because of the electric field on the interface between thorium and tungsten formed due to thorium's greater electropositivity. Since the 1920s, thoriated tungsten wires have been used in electronic tubes and in the cathodes and anticathodes of X-ray tubes and rectifiers. Thanks to the reactivity of thorium with atmospheric oxygen and nitrogen, thorium also acts as a getter for impurities in the evacuated tubes. The introduction of transistors in the 1950s significantly diminished this use, but not entirely.
|
|
Some thyratrons can carry large currents for their physical size. One example is the miniature type 2D21, often seen in 1950s jukeboxes as control switches for relays. A cold-cathode version of the thyratron, which uses a pool of mercury for its cathode, is called an ignitron; some can switch thousands of amperes. Thyratrons containing hydrogen have a very consistent time delay between their turn-on pulse and full conduction; they behave much like modern silicon-controlled rectifiers, also called thyristors due to their functional similarity to thyratrons.
|
|
An arc can be caused by applying voltage to the anode (plate) before the cathode has come up to operating temperature, or by drawing excess current through a rectifier, which damages the emission coating. Arcs can also be initiated by any loose material inside the tube, or by excess screen voltage. An arc inside the tube allows gas to evolve from the tube materials, and may deposit conductive material on internal insulating spacers.. available on the Internet Archive. Chapter 1 Tube rectifiers have limited current capability and exceeding ratings will eventually destroy a tube.
|
|
This begins with the closing of the L-type Ca2+channels, while the K+ channels (from phase 2) remain open. The main potassium channels involved in repolarization are the delayed rectifiers (IKr) and (IKs) as well as the inward rectifier (IK1). Overall there is a net outward positive current, that produces negative change in membrane potential. The delayed rectifier channels close when the membrane potential is restored to resting potential, whereas the inward rectifier channels and the ion pumps remain active throughout phase 4, resetting the resting ion concentrations.
|
|
One of the two cables previously connected to Pole 1 was transferred to Pole 2. On 13 March 2008, Transpower announced that work had been completed to restore 50% of the capacity of Pole 1 to service at times when the demand for power on the North Island peaked. Several mercury arc rectifiers were cannibalized from the Konti-Skan link between Denmark and Sweden for this restoration. The energy transfer on Pole 1 was strictly limited to the northbound direction, to reduce the stress and strain on the aging converter system.
|
|
The use of T1300 stock on the Kolsås Line required several upgrades: the platforms height was raised and the power supply was improved with new rectifiers at Ringstabekk and Kolsås. With the second delivery of T1300 stock in 1980 and 1981, the new units were put into service on the Kolsås Line. The T6 series of fifteen units were built with a driver's cab at both ends, so single-car trains could be operated in the evenings. This resulted in Class D being taken out of use in 1982.
|
|
A linear circuit is one that has no nonlinear electronic components in it. Examples of linear circuits are amplifiers, differentiators, and integrators, linear electronic filters, or any circuit composed exclusively of ideal resistors, capacitors, inductors, op-amps (in the "non-saturated" region), and other "linear" circuit elements. Some examples of nonlinear electronic components are: diodes, transistors, and iron core inductors and transformers when the core is saturated. Some examples of circuits that operate in a nonlinear way are mixers, modulators, rectifiers, radio receiver detectors and digital logic circuits.
|
|
The image was viewed from one side, seeing one of the colors directly and the other being transmitted through the screen from the other side. This was the first single-tube color television system. The earliest test models used screens only a few inches across and had the guns arranged almost at right angles to it, making for a very large tube. Later models were built inside very large Hackbridge-Hewittic (H-H) vacuum tubes, which the company originally designed for use as high-power rectifiers in power supplies.
|
|
The voltage and current at the device terminals follow a load line, and the power dissipation inside the device is large compared with the power delivered to the load. Several attributes dictate how devices are used. Devices such as diodes conduct when a forward voltage is applied and have no external control of the start of conduction. Power devices such as silicon controlled rectifiers and thyristors (as well as the mercury valve and thyratron) allow control of the start of conduction, but rely on periodic reversal of current flow to turn them off.
|
|
The basic moving coil meter is suitable only for direct current measurements, usually in the range of 10 μA to 100 mA. It is easily adapted to read heavier currents by using shunts (resistances in parallel with the basic movement) or to read voltage using series resistances known as multipliers. To read alternating currents or voltages, a rectifier is needed. One of the earliest suitable rectifiers was the copper oxide rectifier developed and manufactured by Union Switch & Signal Company, Swissvale, Pennsylvania, later part of Westinghouse Brake and Signal Company, from 1927.
|
|
By early 4 November shipping containers worth of fusion device arrived by flat bed-truck to the University of Illinois at the Center for Plasma Material Interactions. Aside from lab personnel, the universities Facilities and services division were heavily involved in helping to off load, move in and assemble much of the larger, heavier components. Construction began in earnest with the transformers and rectifiers for the helical and toroidal magnetic coils moving in first. Once these were established then the base was brought in and the yokes, center-stack, half-tori and vertical field coils all installed over the next ten days.
|
|
Bridge rectification has a loss of two diode drops. This reduces output voltage, and limits the available output voltage if a very low alternating voltage must be rectified. As the diodes do not conduct below this voltage, the circuit only passes current through for a portion of each half-cycle, causing short segments of zero voltage (where instantaneous input voltage is below one or two diode drops) to appear between each "hump". Peak loss is very important for low voltage rectifiers (for example, 12 V or less) but is insignificant in high-voltage applications such as HVDC power transmission systems.
|
|
It was used for battery chargers and similar applications from the 1920s until lower-cost metal rectifiers, and later semiconductor diodes, supplanted it. These were made up to a few hundred volts and a few amperes rating, and in some sizes strongly resembled an incandescent lamp with an additional electrode. The 0Z4 was a gas-filled rectifier tube commonly used in vacuum tube car radios in the 1940s and 1950s. It was a conventional full-wave rectifier tube with two anodes and one cathode, but was unique in that it had no filament (thus the "0" in its type number).
|
|
Smoothing the DC voltage can also be effected by inductors, but these are much more expensive, and have relatively large size, and large weight, but would generate much less harmonic currents. Sinusoidal voltage and non-sinusoidal current give a distortion power factor of 0.7 for a computer power supply load. The result of mains rectifiers with connected large value smoothing capacitors is that mains current only flows in the peaks and valleys of the AC wave. Whereas a half cycle of the mains lasts for 10 ms, the mains current flows with large smoothing capacitors for only 3 ms.
|
|
Conversion to DC was by rotary converters, but Melbourne extensions in the 1920s from Croydon and Ringwood used mercury arc rectifiers. Electrification of the Sydney network had been recommended by a Royal Commission in 1909, and in the Bradfield plan of 1915. John Bradfield recommended using 1500 V DC; and this was supported by a conference of Railway Commissioners in 1922 who were anxious to avoid a repeat of the different track gauges used in each state. By this time the 1500 V DC system was used on railways in England, the Netherlands, France and America.
|
|
In 1936, Nathan Rosenstone, along with William Blitzstein, Harold Fishbein, and Morris Allentuck founded Continental Glass Company, which began operations with office space and a warehouse at 524 W. Erie Street in Chicago. In 1937 the company moved to 841 W. Cermak Road, and in 2005 to 230 W. Monroe Street. The core of the business was supplying glass bottles to the beverage industry from Glenshaw Glass to companies such as Pepsi-Cola, 7-Up, Dr Pepper, and a group of small beverage manufacturers. At that time there were also a number of small rectifiers in Chicago.
|
|
In 1936 the first commercial high-voltage direct current (HVDC) line using mercury-arc valves was built between Schenectady and Mechanicville, New York. HVDC had previously been achieved by installing direct current generators in series (a system known as the Thury system) although this suffered from serious reliability issues. In 1957 Siemens demonstrated the first solid-state rectifier (solid-state rectifiers are now the standard for HVDC systems) however it was not until the early 1970s that this technology was used in commercial power systems. In 1959 Westinghouse demonstrated the first circuit breaker that used SF6 as the interrupting medium.
|
|
In 1955 the first railway in Turkey was electrified, on the commuter rail from Sirkeci to Halkalı in Istanbul. In addition to delivery of 18 electric multiple units, TCDD wanted to be able to use electrical engines instead of steam engines on long-haul trains on the last few kilometers into Istanbul. Because the line the locomotives were to serve on was flat and did not allow high speeds, the E4000 was a simple and conservative locomotive, utilizing a direct, single phase AC motor fed directly from the transformer. But even by 1957 the development of rectifiers directly fed AC motors obsolete.
|
|
She is fitted with an extensive suite of equipment for the handling and deploying of undersea cable, including five cable tanks, tension machines, and other devices. She can also be fitted with the Heavy Overboarding System (HOS), a A-frame capable of deploying remotely operated vehicles (ROVs). Five 3,600 brake horsepower General Motors diesels each driving a General Electric 2,500 kVA, 60 Hz, 600 v alternator provided power through a main alternating current bus for all ship power. Fourteen rectifiers from the bus supplied 750 v direct current for the two General Electric 5,000 brake horsepower propulsion motors.
|
|
GreenChip SR is a control circuit for the output stage of power supplies. By replacing diode rectifiers with active MOSFET rectification, GreenChip SR enabled typical loss reductions of 20-30%. In 2006, Philips also introduced the GreenChip PC, a chipset featuring a new topology designed to increase the overall efficiency of desktop PC power supplies to more than 80 percent; at the time, most desktop PC power supplies were only 60 to 70 percent efficient when operating. The GreenChip PC was based on patented Philips technology integrating the standby supply into the main converter, reducing the number of external components required.
|
|
In radio receivers, crystal detectors were often forward-biased with DC current from a battery to make them more sensitive rectifiers. In the course of investigating biased junctions as a technician at Nizhny Novgorod, Losev noticed that when direct current was passed through a silicon carbide (carborundum) point contact junction, a spot of greenish light was given off at the contact point. Losev had constructed a light-emitting diode (LED). Although this effect had been noticed in 1907 by British Marconi engineer Henry Joseph Round, he had just published a brief two paragraph note on it.
|
|
Pacific Gas and Electric Company still provides DC power to some locations in San Francisco, primarily for elevators, supplied by close to 200 rectifiers each providing power for 7–10 customers. The Central Electricity Generating Board in the UK maintained a 200 volt DC generating station at Bankside Power Station in London until 1981. It exclusively powered DC printing machinery in Fleet Street, then the heart of the UK's newspaper industry. It was decommissioned later in 1981 when the newspaper industry moved into the developing docklands area further down the river (using modern AC-powered equipment).
|
|
Regulators powered from AC power circuits can use silicon controlled rectifiers (SCRs) as the series device. Whenever the output voltage is below the desired value, the SCR is triggered, allowing electricity to flow into the load until the AC mains voltage passes through zero (ending the half cycle). SCR regulators have the advantages of being both very efficient and very simple, but because they can not terminate an ongoing half cycle of conduction, they are not capable of very accurate voltage regulation in response to rapidly changing loads. An alternative is the SCR shunt regulator which uses the regulator output as a trigger.
|
|
The CDTA is not free from parasitic input capacitances and it can operate in a wide frequency range due to current-mode operation. Some voltage and current mode applications using this element have already been reported in literature, particularly from the area of frequency filtering: general higher-order filters, biquad circuits, all-pass sections, gyrators, simulation of grounded and floating inductances and LCR ladder structures. Other studies propose CDTA-based high- frequency oscillators. Nonlinear CDTA applications are also expected, particularly precise rectifiers, current-mode Schmitt triggers for measuring purposes and signal generation, current-mode multipliers, etc.
|
|
A crystal radio tuned to a strong local transmitter can be used as a power source for a second amplified receiver of a distant station that cannot be heard without amplification. There is a long history of unsuccessful attempts and unverified claims to recover the power in the carrier of the received signal itself. Traditional crystal sets use half- wave rectifiers. As AM signals have a modulation factor of only 30% by voltage at peaks, no more than 9% of received signal power (P = U^2/R) is actual audio information, and 91% is just rectified DC voltage.
|
|
He graduated in 1948 with his Ph.D. and returned to G.E. Schenectady research labs that summer. While at G.E. during World War II, he developed a magnetron for radar jamming, which led to the development of the microwave oven. While studying the characteristics of p-i-n diodes used as power rectifiers, Hall had a key insight, which resulted in his being co-credited with William Shockley and W. T. Read, Jr., for the analysis of nonradiative carrier recombination in semiconductors. Hall developed the semiconductor laser in 1962, while working at General Electric in Schenectady, New York.
|
|
The scheme involved an extensive network of bribes involving distillers, government officials, rectifiers, gaugers, storekeepers, and internal revenue agents. Essentially, distillers bribed government officials, and those officials helped the distillers evade federal taxes on the whiskey they produced and sold. Due to the increase of liquor taxes after the Civil War, whiskey was supposed to be taxed at 70 cents per gallon, however distillers would instead pay the officials 35 cents per gallon and the illicit whiskey was stamped as having the tax paid. Before they were caught, a group of politicians were able to siphon off millions of dollars in federal taxes.
|
|
At first, the team used motor-generator sets placed in the Anson and Battle fuselages, or batteries connected in various ways as in the earliest sets in the Heyfords. Bowen decided the solution was to build a power supply that would produce all of these DC voltages from a single 240 V 50 Hz supply using transformers and rectifiers. This would allow them to power the radar systems using mains power while the aircraft were on the ground. British aero engines were normally equipped with a power take-off shaft that led to the rear of the engine.
|
|
During the 1960s, French national railway operator SNCF investigated the use of high-power diesel locomotives for heavy express trains on its non-electrified major lines. Following trials of prototype locomotives during the mid-1960s, which were considerably more powerful than any equivalent previously operated by the SNCF, it chose to order 92 locomotives for mixed passenger and high speed freight traffic. Designated CC 72000, the class was a six-axle diesel-electric locomotive. Each locomotive had one SACM 16 cylinder four-stroke diesel engine of 3,550 horsepower (2,650 KW) driving an alternator whose output was rectified by silicon rectifiers.
|
|
Engineering to 1990 – IPENZ, Engineering Publications Co Ltd, Page 38 The terminal stations at each end of HVDC link used large mercury-arc rectifiers and inverters – 1960s technology – to convert between AC and DC. The South Island converter station was established at the Benmore hydroelectric power station in the Waitaki Valley. The North Island converter station was built at Haywards in the Hutt Valley near Wellington. The HVDC transmission line that connects Benmore and Haywards converter stations has an overall length of 610 kilometres. The overhead transmission line is supported by 1649 transmission towers and has a total route length of 570 km.
|
|
One of the first mercury arc bulbs built by Cooper Hewitt In 1882 Jemin and Meneuvrier observed the rectifying properties of a mercury arc. The mercury arc rectifier was invented by Peter Cooper Hewitt in 1902 and further developed throughout the 1920s and 1930s by researchers in both Europe and North America. Before its invention, the only way to convert AC current provided by utilities to DC was by using expensive, inefficient, and high- maintenance rotary converters or motor–generator sets. Mercury-arc rectifiers or "converters" were used for charging storage batteries, arc lighting systems,I.
|
|
During the first 30 days, two errors occurred: one in the closing mechanism of the doors, and one with a switch in the cab that was not water tight. However, it turned out that Oslo Sporveier had not been accurate enough in specifying the energy consumption of the trains, and the rectifiers on parts of the line needed to be upgraded to supply sufficient power to the trains. During 2007, there were four incidents where the trains were not able to brake at stations. The worst incident occurred when a train slid the from Blindern down to Majorstuen.
|
|
Examples of non-linear loads on a power system are rectifiers (such as used in a power supply), and arc discharge devices such as fluorescent lamps, electric welding machines, or arc furnaces. Because current in these systems is interrupted by a switching action, the current contains frequency components that are multiples of the power system frequency. Distortion power factor is a measure of how much the harmonic distortion of a load current decreases the average power transferred to the load. Sinusoidal voltage and non-sinusoidal current give a distortion power factor of 0.75 for this computer power supply load.
|
|
The only locomotives built for British Railways at the works, were the twenty BR Class 28 diesel electrics during 1958-59, and the experimental 25 kV AC locomotive E1000 which was built by converting the gas turbine locomotive 18100. Work commenced in January 1958 when 18100 was brought to Bowesfield Works from storage at Dukinfield Works. The conversion of 18100 involved the removal of the gas turbine unit, generator and the middle traction motor from each bogie, which changed the locomotive from a Co-Co to an A1A-A1A wheel arrangement. The necessary electrical equipment such as the transformer, mercury arc rectifiers and pantograph etc.
|
|
A valve hall is equipped with heating and cooling equipment to control the temperature of the mercury arc rectifiers (which operate best over a narrow temperature range) or thyristors. The valve hall also protects the valves from weather and dust.K. R. Padiyar , HVDC power transmission systems: technology and system interactions New Age International, 1990 , page 30 Several valve assemblies, connected in series for the required terminal voltage, may be installed in the valve hall building. High voltage bushings are supported through the walls of the valve hall, to allow connections between the converter transformers on the one side and the DC switchyard on the other.
|
|
Depending on the type of alternating current supply and the arrangement of the rectifier circuit, the output voltage may require additional smoothing to produce a uniform steady voltage. Many applications of rectifiers, such as power supplies for radio, television and computer equipment, require a steady constant DC voltage (as would be produced by a battery). In these applications the output of the rectifier is smoothed by an electronic filter, which may be a capacitor, choke, or set of capacitors, chokes and resistors, possibly followed by a voltage regulator to produce a steady voltage. More complex circuitry that performs the opposite function, that is converting DC to AC, is called an inverter.
|
|
Two of three high-power thyristor valve stacks used for long-distance transmission of power from Manitoba Hydro dams. Compare with mercury-arc system from the same dam-site, above. In high-power applications, from 1975 to 2000, most mercury valve arc-rectifiers were replaced by stacks of very high power thyristors, silicon devices with two extra layers of semiconductor, in comparison to a simple diode. In medium-power transmission applications, even more complex and sophisticated voltage sourced converter (VSC) silicon semiconductor rectifier systems, such as insulated gate bipolar transistors (IGBT) and gate turn-off thyristors (GTO), have made smaller high voltage DC power transmission systems economical.
|
|
A rotary converter plant in Germany where three phase AC of 50 hertz is transformed into single phase AC of 16.67 hertz for the traction current network AC to DC plant in Baltimore, Maryland, 1910 A rotary converter plant is a facility at which rotary converters convert one form of electricity to another form of electricity. The installed combinations of motors and generators at a plant determine the possible type(s) of conversion. Such facilities also allow the setting of voltages and frequencies, if appropriate equipment is installed. Rotary converter plants were commonplace in railway electrification before the invention of mercury arc rectifiers in the 1920s.
|
|
New characters and segments were introduced including The Rectifiers (a Midlands-based parody of the 60s espionage/sci-fi series, The Champions), Eddie Giraffe (a short but tough New York cop) and Jay Clough (a series of badly edited crime drams from the 1950s). Hugh Pugh and Mr. Ffff were brought over from the original Barry Welsh series. The series' supporting cast consisted of former Barry Welsh is Coming cast members Kim Wall, Gordon Kennedy & Felicity Montagu, actress Harriet Halfhead and singer & television presenter Emma Walford. Only two episodes of the six-part series were broadcast in March 2004 with the remaining four episodes shown in August 2004.
|
|
Electrical accessories, such as the line relays, motor relays and power fuses are mounted in a separate removable chassis called the Electrical Service Unit. A separate shelf is available in the console base for ancillary equipment such as rectifiers and is also used to store local installation documentation. The Teletype Model 28 KSR was produced as a floor, table and wall model. The floor model is 40 inches high, 20.5 inches wide and 18.5 inches deep, excluding the keyboard, and weighs 130 pounds. The table model is 16 inches high, 20.5 inches wide and 18.5 inches deep, excluding the keyboard, and weighs 130 pounds.
|
|
A single story, rectangular shaped building in the Mission Revival style, it was built in 1907 as a traction substation by the Los Angeles Pacific Railway which subsequently became part of the Pacific Electric railway in 1911. Made of brick covered in stucco, the large interior once held old style rotary mechanical rectifiers to convert very high voltage alternating current (AC) to 600 volt direct current (DC) to operate run cars for serve nearby streetcar and interurban lines: the PE's Venice Short Line, Redondo Beach via Playa del Rey Line, and Santa Monica Air Line. Culver City station) and surrounding tracks until 1953. It remained in service until 1953.
|
|
The four classes each took a different approach to the use of the AC supply current. The first, the BB 12000, used DC traction motors with ignitron rectifiers; the BB 13000 used new 50 Hz AC traction motors; the CC 14000 used DC traction motors with rectification by rotary converters and the CC 14100 used three-phase AC traction motors, again with rotary converters. The first two classes were of B′B′ layout with two four wheel bogies and a separate traction motor for each axle. As the axles were mechanically coupled by gearing though, they were classified as B′B′ rather than Bo′Bo′.
|
|
In 1916 he started to study subject of Anode rays and – in 1917 – melting of tungsten (together with Gmür e CO company) and also on mercury Rectifiers. One year later his interests changed to carbon lamps, tungsten smelting and nitrogen combustion. At this time he published also dissertation "Über die Möglichkeit der optischen Abbildung von Molekulargittern" – (About a possibility of optical imaging of molecular gatings) – the world's first concept of holography and the second of the achievements cherished the most by himself. This thesis refers to Wolfke's stay in Karlsruhe in 1912, where he was an assistant to Professor Otto Lehmann – a physicist known as the father of Liquid crystals.
|
|
This increased the capacity of each unit by 40% to 244 seats, and allows the company to manage the annual 10% growth in passengers. The delivery of the fourth cars started in 2008 and were built by Bombardier Transportation, who has bought ADtranz, with the rebuilding scheduled to be completed during 2009. The rebuilding created several challenges for Bombardier, since most of the components used in the class were no longer available. Significant components such as the car body and rectifiers had to be built by Bombardier based on abandoned production lines, and many of the original manufacturers for the interior have become defunct.
|
|
Selenium rectifier A metal rectifier is an early type of semiconductor rectifier in which the semiconductor is copper oxide or selenium. They were used in power applications to convert alternating current to direct current in devices such as radios and battery chargers. Westinghouse Electric was a major manufacturer of these rectifiers since the late 1920s, under the trade name Westector (now used as a trade name for an overcurrent trip device by Westinghouse Nuclear). In some countries the term "metal rectifier" is applied to all such devices; in others the term "metal rectifier" normally refers to copper-oxide types, and "selenium rectifier" to selenium-iron types.
|
|
In 1978, part of the Ferrymead line at Moorhouse station was fitted with overhead catenary and in 1980, some test runs were done with EC 7 at 600 V using the tramway power supply. This led to the acquisition of three mercury-arc rectifiers to power the railway, as well as the trams and trolley-buses. With construction of a substation able to supply the railway, tramway and trolley-buses was subsequently commenced and in November 1988, it was officially opened with trains hauled by EC 7 on the electrified section of the Railway. EC 7 is periodically operated at the Park, usually double-heading with EO 3\.
|
|
The electric components were delivered by Brown, Boveri & Cie of Mannheim, Germany, while the engine-generator was delivered by General Motors. The Di 4 is technically similar to the Denmark's DSB Class ME. Di 4 was the first NSB locomotive to have three-phase and asynchronous motors, and the world's first asynchronous locomotive in revenue service. Henschel was also building the NSB El 17; the two types were planned to use the same traction motors and rectifiers to increase commonality. This was however was discarded because the Di 4's components were too heavy for the El 17. Delivery of the five locomotives took place in 1981.
|
|
This in turn related to the requirement to use DC series motors, which required the current to be converted from AC to DC and for that a rectifier is needed. Until the early 1950s, mercury-arc rectifiers were difficult to operate even in ideal conditions and were therefore unsuitable for use in railway locomotives. It was possible to use AC motors (and some railways did, with varying success), but they have less than ideal characteristics for traction purposes. This is because control of speed is difficult without varying the frequency and reliance on voltage to control speed gives a torque at any given speed that is not ideal.
|
|
In 1933 Mads Clausen (1905-1966) founded Dansk Køleautomatik- og Apparatfabrik, later in 1946 the company name was changed to Danfoss. The first product was an expansion valve for refrigeration units, it was developed after studying imported valves from the US. In 1941, activities are expanded to products for heating. The thermostatic radiator valve was invented by Mads Clausen in 1943, later patented, and in 1952 promoted as an energy saving device. In 1962 the company started production of power electronics, the first product was custom- built rectifiers, later in 1968 production of the VLT Frequency converter began, the first of its kind in the world.
|
|
It is commonly expressed in the central nervous system, but may also be found in pulmonary arteries, auditory outer hair cells, stem cells, the retina, and organs such as the heart and pancreas. Modulation of K+ channel activity and expression has been found to be at the crux of many profound pathophysiological disorders in several cell types. Potassium channels are among the most diverse of all ion channels in eukaryotes. With over 100 genes coding numerous functions, many isoforms of potassium channels are present in the body, but most are divided up into two main groups: inactivating transient channels and non-inactivating delayed rectifiers.
|
|
Coin-operated model train layout in Germany The first clockwork (spring-drive) and live steam locomotives ran until out of power, with no way for the operator to stop and restart the locomotive or vary its speed. The advent of electric trains, which appeared commercially in the 1890s, allowed control of the speed by varying the current or voltage. As trains began to be powered by transformers and rectifiers more sophisticated throttles appeared, and soon trains powered by AC contained mechanisms to change direction or go into neutral gear when the operator cycled the power. Trains powered by DC can change direction by reversing polarity.
|
|
Battery replacement was a major operating cost for early radio receiver users. The development of the battery eliminator, and, in 1925, batteryless receivers operated by household power, reduced operating costs and contributed to the growing popularity of radio. A power supply using a transformer with several windings, one or more rectifiers (which may themselves be vacuum tubes), and large filter capacitors provided the required direct current voltages from the alternating current source. As a cost reduction measure, especially in high-volume consumer receivers, all the tube heaters could be connected in series across the AC supply using heaters requiring the same current and with a similar warm-up time.
|
|
The effects of semiconductor doping were long known empirically in such devices as crystal radio detectors and selenium rectifiers. For instance, in 1885 Shelford Bidwell, and in 1930 the German scientist Bernhard Gudden, each independently reported that the properties of semiconductors were due to the impurities contained within them. The doping process was formally first developed by John Robert Woodyard working at Sperry Gyroscope Company during World War II, with a US Patent issued in 1950.Woodyard, John R. "Nonlinear circuit device utilizing germanium" filed, 1944, granted 1950 The demands of his work on radar denied Woodyard the opportunity to pursue research on semiconductor doping.
|
|
The largest ever mercury-arc rectifiers, built by English Electric, were rated at 150-kV, 1800 A and were used until 2004 at the Nelson River DC Transmission System high-voltage DC-power-transmission project. The valves for the Inter- Island and Kingsnorth projects used four anode columns in parallel, while those of the Nelson River project used six anode columns in parallel in order to obtain the necessary current rating.Cogle, T.C.J, The Nelson River Project - Manitoba Hydro exploits sub-arctic hydro power resources, Electrical Review, 23 November 1973. The Inter-Island link was the last HVDC transmission scheme in operation using mercury arc valves.
|
|
Both glass and metal envelope rectifiers may have control grids inserted between the anode and cathode. Installation of a control grid between the anode and the pool cathode allows control of the conduction of the valve, thereby giving control of the mean output voltage produced by the rectifier. Start of the current flow can be delayed past the point at which the arc would form in an uncontrolled valve. This allows the output voltage of a valve group to be adjusted by delaying the firing point, and allows controlled mercury-arc valves to form the active switching elements in an inverter converting direct current into alternating current.
|
|
For example, an unshrouded 38 GHz microwave dish may have a front to back ratio of 64 dB, while the same size reflector equipped with a shroud would have a front to back ratio of 70 dB. Other factors affecting the front to back ratio of a parabolic microwave antenna include the material of the dish and the precision with which the reflector itself was formed. In other electrical engineering the front to back ratio is a ratio of parameters used to characterize rectifiers or other devices, in which electric current, signal strength, resistance, or other parameters, in one direction is compared with that in the opposite direction.
|
|
Although it gives the correct direction of rectification, it has also been proven that the Mott theory and its Schottky-Davydov extension gives the wrong current limiting mechanism and wrong current-voltage formulae in silicon metal/semiconductor diode rectifiers. The correct theory was developed by Hans Bethe and reported by him in a M.I.T. Radiation Laboratory Report dated November 23, 1942. In Bethe's theory, the current is limited by thermionic emission of electrons over the metal–semiconductor potential barrier. Thus, the appropriate name for the metal–semiconductor diode should be the Bethe diode, instead of the Schottky diode, since the Schottky theory does not predict the modern metal–semiconductor diode characteristics correctly.
|
|
The IMP was a genuine mechanical computer. From the sole solenoid actuator's incremental motion, the horological mechanism derived irregular oscillating functions which in turn rotated the globe and varied its axis, and also moved its two cylindrical indicators for longitude and latitude. Some uncommon, intricate horological devices found in the IMP include cardioid-shaped cam discs, a cone-shaped cam cylinder with a cardioid cross-section and "mechanical rectifiers" which transformed an alternating motion into an analogous, but unidirectional motion (see illustrations). The only other electric actuator used in the IMP instrument was the motor used to fast-forward the mechanism from the actual point-to-nadir to the expected landing point, some 120 degrees further east.
|
|
The CISPR quasi-peak detector is used in EMC testing and is defined in Publication 16 of the International Special Committee on Radio Interference (CISPR) of the International Electrotechnical Commission (IEC). The CISPR quasi-peak detector applied to most conducted emissions measurements (0.15 - 30 MHz) is a detector with an attack time of 1 ms, a decay time of 160 ms and an IF filter setting of 9 kHz. The quasi-peak detector applied to most radiated emissions measurements (30 - 1000 MHz) has an attack time of 1 ms, a decay time 550 ms and an IF filter bandwidth of 120 kHz. In audio quality measurement, quasi- peak rectifiers are specified in several standards.
|
|
The modifications to the projection room included enlarging the area into the rear of the circle so as to accommodate the new Phillips DP70- AAII projectors, the accompanying Mole-Richardson arclamps, Westinghouse Rectifiers and Phillips surround sound per-amplifiers. The MR arclamps only being used for 70mm presentations due to the need for greater light coverage on the larger screen area. For 35mm presentations, on a smaller area of the screen, the MR arclamps were swapped to the more reliable, more efficient Peerless Magnarcs. Besides the alterations to the rear of the circle for the enlargement of the projection room, the circle was also extended toward the screen to increase audience capacity.
|
|
This is followed by the slotted line itself (5) above which is the probe mounted on a movable carriage. The carriage also carries the probe adjustments: (6) is the probe depth adjustment, (7) is a length of co-axial section with tuning adjustments, and (8) is a detector, which uses either a point contact crystal rectifier or a Schottky barrier diode.H. C. Torrey, C. A. Whitmer, Crystal Rectifiers, New York: McGraw-Hill, 1948 The right-hand end of the slotted line is terminated in a matched load (9) which absorbs all the power exiting the end of the waveguide. The load can be replaced by the component or system that it is desired to test.
|
|
HVDC Lehrte–Misburg was an experimental high-voltage direct current transmission line between Hannover-Misburg and Lehrte-Ahlten substation. It was designed by Erwin Otto Marx and served to assess the reliability of its components in continuous service, namely the converters which were based on arc discharges in air in contrast to other projects which use mercury vapour rectifiers. At this time, PreussenElektra had installed a second cable between their transformer stations near Lehrte and Misburg. This was used for the experiments which initially only ran for a few hours at night time due to the requirements for a steady supply of electrical power, and which were extended to two or three days in 1944.
|
|
CSR EMU on the Roca Line in Buenos Aires, using 25 kV AC. This electrification is ideal for railways that cover long distances or carry heavy traffic. After some experimentation before World War II in Hungary and in the Black Forest in Germany, it came into widespread use in the 1950s. One of the reasons why it was not introduced earlier was the lack of suitable small and lightweight control and rectification equipment before the development of solid-state rectifiers and related technology. Another reason was the increased clearance distances required where it ran under bridges and in tunnels, which would have required major civil engineering in order to provide the increased clearance to live parts.
|
|
In low voltage converters (around 10 volts and less), the voltage drop of a diode (typically around 0.7 to 1 volt for a silicon diode at its rated current) has an adverse effect on efficiency. One classic solution replaces standard silicon diodes with Schottky diodes, which exhibit very low voltage drops (as low as 0.3 volts). However, even Schottky rectifiers can be significantly more lossy than the synchronous type, notably at high currents and low voltages. When addressing very low-voltage converters, such as a buck converter power supply for a computer CPU (with a voltage output around 1 volt, and many amperes of output current), Schottky rectification does not provide adequate efficiency.
|
|
Miniature tubes became predominant in consumer applications such as radio receivers and hi-fi amplifiers. However, the larger older styles continued to be used especially as higher-power rectifiers, in higher-power audio output stages and as transmitting tubes. RCA 6DS4 "Nuvistor" triode, circa by Subminiature tubes with a size roughly that of half a cigarette were used in one of the very earliest general-purpose digital computers, the Jaincomp-B, produced by the Jacobs Instrument Company,Pentagon symposium: Commercially Available General Purpose Electronic Digital Computers of Moderate Price, Washington, D.C., 14 MAY 1952 and consumer applications as hearing-aid amplifiers. These tubes did not have pins plugging into a socket but were soldered in place.
|
|
As solid-state metal rectifiers became available for low-voltage rectification in the 1920s, mercury arc tubes became limited to higher voltage and especially high-power applications. Mercury-arc valves were widely used until the 1960s for the conversion of alternating current into direct current for large industrial uses. Applications included power supply for streetcars, electric railways, and variable-voltage power supplies for large radio transmitters. Mercury-arc stations were used to provide DC power to legacy Edison-style DC power grids in urban centers until the 1950s. In the 1960s, solid-state silicon devices, first diodes and then thyristors, replaced all lower-power and lower voltage rectifier applications of mercury arc tubes.
|
|
Trun) in unrebuilt condition, behind it the already rebuilt no 613 (Domat/Ems) with square headlights and an altered position of the number on its nose. In their external appearance, the Ge 4/4 II locomotives, supplied by Swiss Locomotive and Machine Works (SLM) and Brown, Boveri & Cie (BBC), are reminiscent of the Re 4/4II of the Swiss Federal Railways. The electrical componentry is nevertheless markedly different: in the Re 4/4 II locomotives, controlled rectifiers (phase fired controllers) made of thyristors and diodes supply the traction motors with wavy direct current. In a Bo′Bo′ wheel arrangement, the Ge 4/4 II locomotives have a top speed of and weigh .
|
|
Electric operations began on 5 March 1908 utilizing two combination passenger with baggage section motor cars with pantographs for current pickup from the overhead wire, two passenger only motor cars similarly equipped, two unpowered passenger cars for powered cars to tow, and a 47-ton Baldwin-Westinghouse box cab freight locomotive. Motor powered equipment carried on-board transformers and rectifiers to convert the 3300 volt AC to the DC required by the traction motors. The line originated at the Visalia train station on the southeast corner of Garden and Oak Streets. In 1916 a new depot was built on the block just west, the second block north and the second block east of the center of town (Court and Main Streets.).
|
|
Included in this portion of the syllabus are thermionic emissions with their characteristic curves, diodes, triodes and multi- electrode valves; and the use of valves as rectifiers, oscillators, amplifiers, detectors and frequency changers, stabilisation and smoothing. Radio receivers is the fourth topic that covers the principles and operation of TRF receivers and Superheterodyne receivers, CW reception; with receiver characteristics such as sensitivity, selectivity and fidelity; Adjacent- channel interference and image interference; AGC and squelch; and signal to noise ratio (S/R). Similarly, the next topic on transmitters covers the principles and operation of low power transmitters; oscillators such as the Colpitts oscillator, Hartley oscillator, crystal oscillators, and stability of oscillators. The last three topics deal with radio propagation, aerials, and frequency measurement.
|
|
Kepler, one section of Kendall Band, in 2011 The Cambridge subway opened from Park Street Under to Harvard on March 23, 1912, with intermediate stops at Central and Kendall. From the early 20th century through the 1970s, the MBTA operated a powerhouse above ground in Kendall Square, including rotary converters (also called cycloconverters) to transform incoming AC electrical power to 600 volts DC power fed to the third rail to run the subway. An old-fashioned cycloconverter consisted of an AC motor coupled to a huge, slowly rotating flywheel coupled to a DC generator, hence the name. Despite the development of compact low-maintenance semiconductor- based power rectifiers, the long-obsolete electromechanical technology still occupied prime real estate in the heart of Kendall Square.
|
|
Interior of a Budd Silverliner showing the leatherette decor applied to cars 259, 269, 9012 and 9015 in place of the standard "Ketchup and Mustard" styling. The design of the Budd Silverliner was based on a lightweight stainless steel body and frame coupled to an advanced AC/DC rectifier propulsion system and new lightweight, high-speed trucks. While largely identical to the earlier Pioneer III's, differences included a single-arm Faiveley pantograph, a state-of-the-art propulsion system that made use of solid-state phase angle controllers coupled to mercury arc ignitron rectifiers, higher-powered motors, a higher-capacity main transformer, multi- function couplers and disc brakes. One result of these upgrades was that the Silverliners were incompatible with the six Pioneer prototypes.
|
|
The EMD F40PH (left) and MPI MPXpress-series MP36PH-3S (right) locomotives coupled together by Metra use diesel–electric transmission. 2TE10M locomotive Class 742 and 743 locomotive Originally, the traction motors and generator were DC machines. Following the development of high-capacity silicon rectifiers in the 1960s, the DC generator was replaced by an alternator using a diode bridge to convert its output to DC. This advance greatly improved locomotive reliability and decreased generator maintenance costs by elimination of the commutator and brushes in the generator. Elimination of the brushes and commutator, in turn, disposed of the possibility of a particularly destructive type of event referred to as a flashover, which could result in immediate generator failure and, in some cases, start an engine room fire.
|
|
In late 1916, P. R. Mallory formed the Liberty Electric Corporation to manufacture radio transmitters and receivers for the U.S. government during World War One, and hired Shoemaker to be the company's Chief Engineer. At the close of the war, Mallory formed the Independent Wireless Telegraph Company, with Shoemaker continuing to act as Chief Engineer until the Radio Corporation of America purchased the company in 1925. When P. R. Mallory moved the manufacturing activities from New York City to Indiana, Shoemaker resigned and remained in the east doing independent consulting. In May 1932 he was again employed by P. R. Mallory and Company, to conduct research work on dry plate rectifiers at the laboratory of Samuel Ruben (the founder of Duracell Battery) in New Rochelle, New York.
|
|
There were few problems in the start, although the pantographs had technical problems and there were occasional power failures in the overhead wires due to out-of-date rectifiers not being able to handle the increase power usage. Trams no. 101 through 113 were put into service on Line 9 on the Lilleaker Line and the Ekeberg Line, replacing the Class E. The remaining trams of the first series were put into service on Line 1, on the Sinsen Line and the Briskeby Line, as well as Line 7, on the Ullevål Hageby Line and the Sinsen Line. On Line 9, that included both the tramway's light rail sections, only SL79-trams were used, while lines 1 and 7 used a mix of SL79 and SM53-trams.
|
|
Available online. or nonlinear microwave absorbers and loads.Christianson, A. and Chappell, W. J. Measurement of ultra low passive intermodulation with ability to separate current/voltage induced nonlinearities, in IEEE Microwave Theory and Techniques Society International Microwave Symposium, Boston, MA, 2009, pp. 1301-1304. Available online. Corroded materials on antennas, waveguides, or even structural elements, can act as one or more diodes. (Crystal sets, early radio receivers, used the semiconductor properties of natural galena to demodulate the radio signal, and copper oxide was used in power rectifiers.) This gives rise to undesired interference, including the generation of harmonics or intermodulation. Rusty objects that should not be in the signal- path, including antenna structures, can also reradiate radio signals with harmonics and other unwanted signals.
|
|
The first semiconductor device used in power circuits was the electrolytic rectifier - an early version was described by a French experimenter, A. Nodon, in 1904. These were briefly popular with early radio experimenters as they could be improvised from aluminum sheets, and household chemicals. They had low withstand voltages and limited efficiency.Bernard Finn, Exposing Electronics, CRC Press, 2000 pages 14-15 The first solid-state power semiconductor devices were copper oxide rectifiers, used in early battery chargers and power supplies for radio equipment, announced in 1927 by L.O. Grundahl and P. H. Geiger.Peter Robin Morris, A History of the World Semiconductor Industry, IET 1990 page 18 The first germanium power semiconductor device appeared in 1952 with the introduction of the power diode by R.N. Hall.
|
|
The two were planned to have the same rectifiers and motors, but due to weight restrictions the El 17 received the same type as Class 120.Aspenberg, 2001: 118–119 The first six locomotives, numbered 2221–2226, were delivered in 1982. At the same time, the delivery of the B7 passenger cars from Strømmens Verksted was made, and the first train with an El 17 and B7s in regular service operated on the Dovre Line on 14 September 1982. The El 17 was plagued with problems (overheated components, etc.), and NSB quickly decided to operate them in pairs in case one unit should fail. On 6 July 1982, there was a fire in 2224, and it was sent to Thyssen-Henschel to be redesigned.
|
|
Normal (p–n) diodes, which operate as described above, are usually made of doped silicon or germanium. Before the development of silicon power rectifier diodes, cuprous oxide and later selenium was used. Their low efficiency required a much higher forward voltage to be applied (typically 1.4 to 1.7 V per "cell", with multiple cells stacked so as to increase the peak inverse voltage rating for application in high voltage rectifiers), and required a large heat sink (often an extension of the diode's metal substrate), much larger than the later silicon diode of the same current ratings would require. The vast majority of all diodes are the p–n diodes found in CMOS integrated circuits, which include two diodes per pin and many other internal diodes.
|
|
In the clinical setting, the function of the internode can only be explored by excitability studies (see Measurement). Experimental observations utilizing threshold measurements to assess excitability of myelinated nerve fibers have indicated that the function of regenerated internodes indeed remains persistently abnormal, with regenerated motor axons displaying increased rheobase and decreased chronaxie—changes that are consistent with abnormal active membrane properties. These studies have furthermore determined that activity-dependent conduction block in myelination was due to hyperpolarization, as well as abnormally increased Na+ currents and increased availability of fast K+ rectifiers. Listed below are findings on the changes in nerve excitability, and therefore the strength-duration time constant, that have been observed within several of the most pervasive nerve disorders.
|
|
CFL Cold cathodes are used in cold-cathode rectifiers, such as the crossatron and mercury-arc valves, and cold-cathode amplifiers, such as in automatic message accounting and other pseudospark switching applications. Other examples include the thyratron, krytron, sprytron, and ignitron tubes. A common cold- cathode application is in neon signs and other locations where the ambient temperature is likely to drop well below freezing, The Clock Tower, Palace of Westminster (Big Ben) uses cold-cathode lighting behind the clock faces where continual striking and failure to strike in cold weather would be undesirable. Large cold-cathode fluorescent lamps (CCFLs) have been produced in the past and are still used today when shaped, long-life linear light sources are required.
|
|
Several electric locomotives, including the New Haven EP5 and the Virginian EL-C, carried ignitrons on board to rectify incoming AC to traction motor DC. A 150-kilovolt, 1800 amp mercury-arc valve at Manitoba Hydro's Radisson converter station, August 2003 One of the last major uses of mercury arc valves was in HVDC power transmission, where they were used in many projects until the early 1970s, including the HVDC Inter-Island link between the North and South Islands of New Zealand and the HVDC Kingsnorth link from Kingsnorth power station to London.Calverley T.E., Gavrilovic, A., Last F.H., Mott C.W., The Kingsnorth-Beddington-Willesden DC Link, CIGRE session, Paris, 1968. However, starting about 1975, silicon devices have made mercury-arc rectifiers largely obsolete, even in HVDC applications.
|
|
Mariusz Malinowski received the Ph.D. degree with honors in Electrical Engineering from the Warsaw University of Technology (WUT) in 2001 for his thesis entitled "Sensorless control strategies for three-phase PWM rectifiers". He then attained a habilitation for monothematic publications entitled "Selected problems of modulation and control for two- and multilevel voltage source converters with PWM" in 2012. He is employed as professor at WUT. His public service include activity in IEEE (Institute of Electrical and Electronics Engineers), where he was editor-in-chief of IEEE Industrial Electronics Magazine during 2010-2012 (Award of Excellence given by Society for Technical Communications), Associate Editor of IEEE Transactions on Industrial Electronics since 2005, and Associate Editor of IEEE Transactions on Power Electronics since 2012.
|
|
With AC input, the output of a diode bridge (called a full-wave rectifier for this purpose; there is also half-wave rectification, which does not use a diode bridge) is polarized pulsating non-sinusoidal voltage of the same amplitude but twice the frequency of the input. It may be considered as DC voltage upon which is superimposed a very large ripple voltage. This kind of electric power is not very usable, because ripple is dissipated as waste heat in DC circuit components and may cause noise or distortion during circuit operation. So nearly all rectifiers are followed by a series of bandpass or bandstop filters and/or a voltage regulator to convert most or all of the ripple voltage into a smoother and possibly higher DC output.
|
|
Miniature receiving tubes for line-operated equipment use on the order of 0.5 to 4 watts for heater power; high power tubes such as rectifiers or output tubes use on the order of 10 to 20 watts, and broadcast transmitter tubes might need a kilowatt or more to heat the cathode.Sōgo Okamura History of electron tubes, IOS Press, 1994 , pp. 106, 109, 120, 144, 174 The voltage required is usually 5 or 6 volts AC. This is supplied by a separate 'heater winding' on the device's power supply transformer that also supplies the higher voltages required by the tubes' plates and other electrodes. One approach used in transformerless line- operated radio and television receivers such as the All American Five is to connect all the tube heaters in series across the supply line.
|
|
Such rectifiers may be used for battery charging, electrolysis processes such as aluminium production or for operation of DC motors. "Zig-zag" transformers may make the equivalent of six-phase full-wave rectification, twelve pulses per cycle, and this method is occasionally employed to reduce the cost of the filtering components, while improving the quality of the resulting DC. Three phase plug commonly used on electric stoves in Germany One example of a three- phase load is the electric arc furnace used in steelmaking and in refining of ores. In many European countries electric stoves are usually designed for a three-phase feed. Individual heating units are often connected between phase and neutral to allow for connection to a single-phase circuit if three-phase is not available.
|
|
Converting DC power from one voltage to another is much more complicated. One method of DC-to-DC conversion first converts power to AC (using a device called an inverter), then uses a transformer to change the voltage, and finally rectifies power back to DC. A frequency of typically several tens of kilohertz is used, as this requires much smaller inductance than at lower frequencies and obviates the use of heavy, bulky, and expensive iron-cored units. Another method of converting DC voltages uses a charge pump, using rapid switching to change the connections of capacitors; this technique is generally limited to supplies up to a couple of watts, owing to the size of capacitors required. Output voltage of a full-wave rectifier with controlled thyristors Rectifiers are also used for detection of amplitude modulated radio signals.
|
|
A multi-service access node (MSAN), also known as a multi-service access gateway (MSAG), is a device typically installed in a telephone exchange (although sometimes in a roadside serving area interface cabinet) which connects customers' telephone lines to the core network, to provide telephone, ISDN, and broadband such as DSL all from a single platform. Prior to the deployment of MSANs, telecom providers typically had a multitude of separate equipment including DSLAMs to provide the various types of services to customers. Integrating all services on a single node, which typically backhauls all data streams over IP or Asynchronous Transfer Mode can be more cost effective and may provide new services to customers more quickly than previously possible. A typical outdoor MSAN cabinet consists of narrowband (POTS), broadband (xDSL) services, batteries with rectifiers, optical transmission unit and copper distribution frame.
|
|
For the first two albums, he used Mesa Boogie Dual Rectifiers and modified Marshall 1959SLP reissue heads live and in the studio, but during the recording of Minutes to Midnight Delson decided not to use much of his old equipment to give him a new sound. Delson used several vintage and rare amplifiers such as Soldano SLO's, Marshall JCM 800, Mesa Boogie Dual Rectifier, a 1972 50 watt Hiwatt Custom, a Bogner Uberschall, and an extremely rare Bo Diddley amplifier with an onboard tape delay that was probably made for Diddley by Watkins (WEM). During live performances Delson relies on several Randall MTS Modules to recreate the sound from these different amplifiers. In 2014, the Randall rig was eventually phased out for a Fractal Axe-FX II setup, which is run direct into the PA system and a Matrix GT1000FX power amp.
|
|
In the late 1960s, the electrical industry was revolutionised as GEC acquired Associated Electrical Industries (AEI) in 1967, which encompassed Metropolitan-Vickers, British Thomson-Houston, Edison Swan, Elliott Brothers, Siemens Brothers & Co, Hotpoint, William Thomas Henley and Birlec. In 1968, GEC merged with English Electric, incorporating Elliott Brothers, the Marconi Company, Ruston & Hornsby, Robert Stephenson & Hawthorns, the Vulcan Foundry, Willans & Robinson and Dick, Kerr & Co. The Witton works remained one of the company's biggest sites, producing high-voltage switchgear and transformers, small motors, mercury arc rectifiers and traction components, until the plant was gradually sold off by Weinstock in 1969. In 1969, a new subsidiary company was born, English Electric-AEI Traction Ltd. This new organisation slowly integrated together the traction divisions of both AEI and EE, culminating in 1972 when the company was renamed GEC Traction Ltd.
|
|
However, the latter still had too short platforms. No. 141 and 151 awaiting departure on each their line at Rikshospitalet Operation proved to give several major difficulties, and by March 2001, Oslo Sporveier was threatening to terminate the purchase agreement unless the manufacturer—who by then had merged to become AnsaldoBreda—fixed the problems. These included the noise being 15 dB too loud, and trams being out of service during the January–February cold spell, when batteries and rectifiers would not operate. It was agreed that AnsaldoBreda would have to replace all 256 motors to satisfy the criteria in the contract. By 1 June, AnsaldoBreda had delivered one tram that met all the contract's criteria. Tram 155 was by then still undelivered, and was being used for testing by the manufacturer. At the same time, 149 was being used for tests in Oslo.
|
|
At some point the old mercury arc rectifiers were replaced by the more reliable silicon controlled variety, the HVAC was updated with ozone safe refrigerant, the PCBs were removed in the transformer coolant and the bathrooms were closed in those cars that had them. By the year 2000 SEPTA began to plan for the retirement of the Budd Silverliners, which had not only reached the end of their design life, but their lack of dynamic brakes and manually worked doors were presenting growing operational headaches. However a prolonged procurement process as well as delays in delivering the replacement Silverliner V cars resulted in the Budds lasting in service well into 2012, a run of nearly 50 years. The final run took place on June 29, 2012 with former Reading car #9010 running with Silverliner III #235 on the Cynwyd Line.
|
|
It was soon made obsolete by newer developments, and the technology lay more or less dormant for years. The inductive output tube has re-emerged within the last twenty years after having been discovered to possess particularly suitable characteristics (broadband linearity) for the transmission of digital television and high-definition digital television. In research undertaken prior to the transition from analog to digital television broadcasting, it was discovered that electromagnetic interference from lightning, high voltage AC power transmission, AC rectifiers, and ballasts used in fluorescent lighting, greatly affected low-band VHF channels (In North America, channels 2,3,4,5, & 6) making it difficult to impossible to use them for digital television. These low-numbered channels were often the first television broadcasters in a given city, and were often large, vital operations which had no choice but to relocate to UHF.
|
|
The exciter output is rectified by a 3-phase bridge-connected group of silicon diodes which are natural air cooled and accommodated in a bank of nine cubicles located on a platform cantilevered from the side of the foundation block. Mounted adjacent to the rectifiers is the main field suppression circuit-breaker which incorporates a discharge resistance and auxiliary switch to close the discharge circuit. A permanent magnet high frequency generator, directly coupled to the exciter shaft, acts as a pilot exciter and supplies the exciter field via a power stage magnetic amplifier which may be regulated either by manual control or by the automatic voltage regulator. The AVR is a continuously acting regulator including such features as VAR limiting, automatic follow-up of manual control, and protection against over fluxing or over exciting of the main generator.
|
|
Welding power supplies may also use generators or alternators to convert mechanical energy into electrical energy. Modern designs are usually driven by an internal combustion engine but older machines may use an electric motor to drive an alternator or generator. In this configuration the utility power is converted first into mechanical energy then back into electrical energy to achieve the step-down effect similar to a transformer. Because the output of the generator can be direct current, or even a higher frequency AC, these older machines can produce DC from AC without any need for rectifiers of any type, or can also be used for implementing formerly-used variations on so-called heliarc (most often now called TIG) welders, where the need for a higher frequency add-on module box is avoided by the alternator simply producing higher frequency ac current directly.
|
|
The power electronics in the converters use newly available IGBTs, supplied by American semiconductor manufacturer IXYS Corporation, rather than the originally foreseen but unreliable IGCTs of the HSR-350x. Each traction converter consists of two parallel-switched four-quadrant converters, which function as rectifier modules by converting single-phase alternating current (AC) from one main transformer winding each to direct current (DC), a 2,800 V DC intermediate circuit, and one inverter module converting the DC supply to the three-phase AC supply for traction motors. Each converter supplies the motors on two axles of a bogie, providing for individual bogie control. All auxiliary power is supplied by separate 1 MW auxiliary units, one per traction head, consisting of two pairs of parallel-switched IGBT-based converter modules acting as rectifiers between one main transformer winding and the 670 V DC head end power.
|
|
Zero crossing (or burst-firing) control is an approach for electrical control circuits that starts operation with the AC load voltage at close to 0 volts in the AC cycle. This is in relation to solid state relays, such as triacs and silicon controlled rectifiers. The purpose of the circuit is to start the triac conducting very near the time point when the load voltage is crossing zero volts (at the beginning or the middle of each AC cycle represented by a sine wave), so that the output voltage begins as a complete sine-wave half- cycle. In other words, if the controlling input signal is applied at any point during the AC output wave other than very close to the zero voltage point of that wave, the output of the switching device will "wait" to switch on until the output AC wave reaches its next zero point.
|
|
Schematic diagram of diesel–electric locomotive In a diesel–electric locomotive, the diesel engine drives either an electrical DC generator (generally, less than net for traction), or an electrical AC alternator-rectifier (generally net or more for traction), the output of which provides power to the traction motors that drive the locomotive. There is no mechanical connection between the diesel engine and the wheels. The important components of diesel–electric propulsion are the diesel engine (also known as the prime mover), the main generator/alternator-rectifier, traction motors (usually with four or six axles), and a control system consisting of the engine governor and electrical or electronic components, including switchgear, rectifiers and other components, which control or modify the electrical supply to the traction motors. In the most elementary case, the generator may be directly connected to the motors with only very simple switchgear.
|
|
Because thyristors (and mercury rectifiers) can only be turned on (not off) by control action, and rely on the external AC system to effect the turn-off process, the control system only has one degree of freedom – when in the cycle to turn on the thyristor. This limits the usefulness of HVDC in some circumstances because it means that the AC system to which the HVDC converter is connected must always contain synchronous machines in order to provide the timing for the commutating voltage – the HVDC converter cannot feed power into a passive system. This is not a problem supplying additional power to a grid that is already live, but cannot be used as the sole source of power. With other types of semiconductor device such as the insulated-gate bipolar transistor (IGBT), both turn-on and turn-off timing can be controlled, giving a second degree of freedom.
|
|
Many potential rectifying molecules were studied by the groups of Robert Melville Metzger, Charles A. Panetta, and Daniell L. Mattern (University of Mississippi) between 1981 and 1991, but were not tested successfully for conductivity. This proposal was verified in two papers in 1990 and 1993 by the groups of John Roy Sambles (University of Exeter, UK) and Geoffrey Joseph Ashwell (Cranfield University now at the Lancaster University, UK), using a monolayer of hexadecylquinolinium tricyanoquinodimethanide sandwiched between dissimilar metal electrodes (magnesium and platinum) and then confirmed in three papers in 1997 and 2001 by Metzger (now at the University of Alabama) and coworkers, who used identical metals (first aluminium, then gold). These papers use Langmuir-Blodgett monolayers (one molecule thick) with an estimated 1014 to 1015 molecules measured in parallel. About nine similar rectifiers of vastly different structure have been found by Metzger's group between 1997 and 2006.
|
|
The rectification property of metal–semiconductor contacts was discovered by Ferdinand Braun in 1874 using mercury metal contacted with copper sulfide and iron sulfide semiconductors. Sir Jagadish Chandra Bose applied for a US patent for a metal-semiconductor diode in 1901. This patent was awarded in 1904. G.W. Pickard received a patent in 1906 on a point-contact rectifier using silicon. In 1907, George W. Pierce published a paper in Physical Review showing rectification properties of diodes made by sputtering many metals on many semiconductors. The use of the metal–semiconductor diode rectifier was proposed by Lilienfeld in 1926 in the first of his three transistor patents as the gate of the metal–semiconductor field effect transistors. The theory of the field-effect transistor using a metal/semiconductor gate was advanced by William Shockley in 1939. The earliest metal–semiconductor diodes in electronics application occurred around 1900, when the cat's whisker rectifiers were used in receivers.
|
|
These amplifiers shared nearly identical circuits, with two (or four) 5881/6L6GC tubes in fixed-bias Class AB configuration, long-tailed pair phase inverters, and dual "normal" and "vibrato" channels with independent volume and tone controls; the models were differentiated only by cabinet/speaker configurations, transformers, and rectifiers. The tremolo ("vibrato") circuit which the Vibrasonic premiered and which gave it its name more closely resembled a Vox tremolo circuit than anything which Fender used before or after, a complex "harmonic vibrato" which created the illusion of true pitch-shifting. Two tubes (5G13 model) and later three tubes (6G13-A model) were used in the tremolo circuit alone and this perhaps explains why it was not widely used, and abandoned in the mid-1960s "blackface" amps. The 1×15 Vibrasonic, like the 4×10 Concert-Amp, featured a larger interleaved output transformer designed to minimize distortion and maximize clean headroom in the output stage.
|
|
The level specification is meant at 1000 Hz. The reading should not depart from the reading at 1000 Hz by more than 0.2 dB from 35 Hz to 10 kHz or more than 0.5 dB between 25 Hz and 16 kHz. Note that the specification mentions only sinusoid waveforms. Given the electromechanical principle of the meter, the deviation of the needle is actually approximately proportional to the average of the part of the signal with more than approximately 0.4 V instantaneously because of the two copper- oxide rectifiers always in series, which transfer function curve has a knee around 0.2 V. Signals generally do not have a sinusoidal waveform by far, even if they all fall within the VU-meter bandpass. The reading is the average of the voltage,Average Voltage Tutorial and is not an indication of the power of the signal, which is proportional to the average of the square of the voltage, or the root-mean-square (RMS) value.
|
|
1N4001 diode in DO-41 axial package (through hole mount) SMA) package (surface mount version of 1N4007 that is common in Asia) schematic symbol for general-purpose silicon rectifier diodes 6A8 diode in a large axial package from Master Instrument Corporation (MIC) Current-voltage characteristics of a 1N4001 at different temperatures The 1N400x (or 1N4001 or 1N4000Though some writers and datasheets refer to "1N4000 series", a 1N4000 is a 10-watt Zener diode unrelated to the 1N4001 series of 1 ampere rectifiers.) series is a family of popular one-ampere general-purpose silicon rectifier diodes commonly used in AC adapters for common household appliances. Its blocking voltage varies from 50 volts (1N4001) to 1000 volts (1N4007). This JEDEC device number series is available in the DO-41 axial package, and similar diodes are available in SMA and MELF surface mount packages (in other part number series). The 1N540x (or 1N5400) series is a similarly popular family of diodes for higher-current 3 A applications.
|
|
The locomotive is known for its simplicity in operating - in the cab, original versions have a dashboard with a panel for gauges and switches, a throttle/dynamic brake wheel and brake levers, alongside with a knob for the horn, which has low/high and soft/hard tones and Hasler Bern speedometers (mostly replaced by Softronic IVMS speedometers). Subsequently upgraded versions changed that, with the ICOL cabs featuring a throttle/dynamic brake lever, the dashboard is higher and features an on-board computer, and 2 buttons that remove the horn's ability to use the soft/hard tonnes. Certain modernizations (such as by PROMAT but in lower numbers) maintain the "wheel" but have a renovated dashboard, somewhat similar to the CFR Class 46. Inside the machines' hall, electric current enters into the oil-cooled transformer, where it is converted from 25 kV AC to 1.5 kV, passing through silicon diode rectifiers where it is converted into DC current for the ASEA LJE 108 traction motors.
|
|
The controllability of a current-flow through HVDC rectifiers and inverters, their application in connecting unsynchronized networks, and their applications in efficient submarine cables mean that HVDC interconnections are often used at national or regional boundaries for the exchange of power (in North America, HVDC connections divide much of Canada and the United States into several electrical regions that cross national borders, although the purpose of these connections is still to connect unsynchronized AC grids to each other). Offshore windfarms also require undersea cables, and their turbines are unsynchronized. In very long-distance connections between two locations, such as power transmission from a large hydroelectric power plant at a remote site to an urban area, HVDC transmission systems may appropriately be used; several schemes of these kind have been built. For interconnections to Siberia, Canada, India, and the Scandinavian North, the decreased line-costs of HVDC also make it applicable, see List of HVDC projects.
|
|
A total of 38 cars were purchased for the PRR with the remaining 17 going to the Reading. While some referred to the new vehicles as "PSIC Cars", the modern stainless steel body shells quickly defined the fleet and the name "Silverliner" was soon adopted. Differences from the earlier Pioneer IIIs included a single arm Faiveley pantograph, a state of the art propulsion system that made use of solid state phase angle controllers coupled to mercury arc ignitron rectifiers and higher powered motors. Like the Pioneer IIIs before them, the Silverliners offered their riders air cushion suspension, air conditioning, electric train heat and a nearly silent ride. With 150 hp more than the Pioneer III cars (550 hp total) the Silverliners could achieve a 1.7 mph/s acceleration rate which was quite higher than the older MP54s and multi- function couplers and disc brakes further improved performance. The 38 PRR cars were numbered in two series, 201-219 and 251-269 and given PRR classification MP85B, while the 17 Reading cars were numbered 9001-9017 and given Reading classification REB-13.
|
|