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Booster (electric Power)
A booster was a motor–generator (MG) set used for voltage regulation in direct current (DC) electrical power circuits. The development of alternating current and solid-state devices has rendered it obsolete. Boosters were made in various configurations to suit different applications. Line booster In the days of direct current mains, voltage drop along the line was a problem so line boosters were used to correct it. Suppose that the mains voltage was 110 V. Houses near the power station would receive 110 volts but those remote from the power station might receive only 100 V so a line booster would be inserted at an appropriate point to "boost" the voltage. It consisted of a motor, connected in parallel with the mains, driving a generator, in series with the mains. The motor ran at the depleted mains voltage of 100 V and the generator added another 10 V to restore the voltage to 110 V. This was an inefficient system and was made obsolete by the development of alternating cur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Motor–generator
A motor–generator (an M–G set) is a device for converting electrical power to another form. Motor–generator sets are used to convert frequency, voltage, or phase of power. They may also be used to isolate electrical loads from the electrical power supply line. Large motor–generators were widely used to convert industrial amounts of power while smaller motor–generators (such as the one shown in the picture) were used to convert battery power to higher DC voltages. While a motor–generator set may consist of distinct motor and generator machines coupled together, a single unit dynamotor (for dynamo–motor) has the motor coils and the generator coils wound around a single rotor; both the motor and generator therefore share the same outer field coils or magnets.Radio Amateur's Handbook 1976, pub. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Switch
In electrical engineering, a switch is an electrical component that can disconnect or connect the conducting path in an electrical circuit, interrupting the electric current or diverting it from one conductor to another. The most common type of switch is an electromechanical device consisting of one or more sets of movable electrical contacts connected to external circuits. When a pair of contacts is touching current can pass between them, while when the contacts are separated no current can flow. Switches are made in many different configurations; they may have multiple sets of contacts controlled by the same knob or actuator, and the contacts may operate simultaneously, sequentially, or alternately. A switch may be operated manually, for example, a light switch or a keyboard button, or may function as a sensing element to sense the position of a machine part, liquid level, pressure, or temperature, such as a thermostat. Many specialized forms exist, such as the toggle swi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electric Motors
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. An electric generator is mechanically identical to an electric motor, but operates with a reversed flow of power, converting mechanical energy into electrical energy. Electric motors can be powered by direct current (DC) sources, such as from batteries, or rectifiers, or by alternating current (AC) sources, such as a power grid, inverters or electrical generators. Electric motors may be classified by considerations such as power source type, construction, application and type of motion output. They can be powered by AC or DC, be brushed or brushless, single-phase, two-phase, or three-phase, axial or radial flux, and may be air-cooled or liquid-cooled. Standardized motors provide c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Repeater
In telecommunications, a repeater is an electronic device that receives a signal and retransmits it. Repeaters are used to extend transmissions so that the signal can cover longer distances or be received on the other side of an obstruction. Some types of repeaters broadcast an identical signal, but alter its method of transmission, for example, on another frequency or baud rate. There are several different types of repeaters; a telephone repeater is an amplifier in a telephone line, an optical repeater is an optoelectronic circuit that amplifies the light beam in an optical fiber cable; and a radio repeater is a radio receiver and transmitter that retransmits a radio signal. A broadcast relay station is a repeater used in broadcast radio and television. Overview When an information-bearing signal passes through a communication channel, it is progressively degraded due to loss of power. For example, when a telephone call passes through a wire telephone line, some of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boost Converter
A boost converter (step-up converter) is a DC-to-DC power converter that steps up voltage (while stepping down current) from its input (supply) to its output (load). It is a class of switched-mode power supply (SMPS) containing at least two semiconductors (a diode and a transistor) and at least one energy storage element: a capacitor, inductor, or the two in combination. To reduce voltage ripple, filters made of capacitors (sometimes in combination with inductors) are normally added to such a converter's output (load-side filter) and input (supply-side filter). Overview Power for the boost converter can come from any suitable DC source, such as batteries, solar panels, rectifiers, and DC generators. A process that changes one DC voltage to a different DC voltage is called DC to DC conversion. A boost converter is a DC to DC converter with an output voltage greater than the source voltage. A boost converter is sometimes called a step-up converter since it "steps up" the sourc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cathode Ray Tube
A cathode-ray tube (CRT) is a vacuum tube containing one or more electron guns, which emit electron beams that are manipulated to display images on a phosphorescent screen. The images may represent electrical waveforms ( oscilloscope), pictures ( television set, computer monitor), radar targets, or other phenomena. A CRT on a television set is commonly called a picture tube. CRTs have also been used as memory devices, in which case the screen is not intended to be visible to an observer. The term '' cathode ray'' was used to describe electron beams when they were first discovered, before it was understood that what was emitted from the cathode was a beam of electrons. In CRT television sets and computer monitors, the entire front area of the tube is scanned repeatedly and systematically in a fixed pattern called a raster. In color devices, an image is produced by controlling the intensity of each of three electron beams, one for each additive primary color (red, gre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metadyne
A metadyne is a direct current electrical machine with two pairs of brushes. It can be used as an amplifier or rotary transformer. It is similar to a third brush dynamo but has additional regulator or "variator" windings. It is also similar to an amplidyne except that the latter has a compensating winding which fully counteracts the effect of the flux produced by the load current. The technical description is "a cross-field direct current machine designed to utilize armature reaction". A metadyne can convert a constant-voltage input into a constant-current, variable-voltage output. History The word ''metadyne'' is derived from the Greek words for conversion of power. While the name is believed to have been coined by Joseph Maximus Pestarini (Italian language Giuseppe Massimo Pestarini) in a paper which he submitted to the Montefiore International Contest at Liège, Belgium in 1928, the type of machine which it described had been known since the 1880s. The first known British pate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
London Underground O Stock
The London Underground O and P Stock electric multiple units were used on the London Underground from 1937 to 1981. O Stock trains were built for the Hammersmith & City line, using metadyne control equipment with regenerative braking, but the trains were made up entirely of motor cars and this caused technical problems with the traction supply so trailer cars were added. P Stock cars were built to run together with the O Stock cars now surplus on Metropolitan line Uxbridge services. The trains had air-operated sliding doors under control of the guard; the O Stock with controls in the cab whereas the P Stock controls in the trailing end of the motor cars. The P Stock was introduced with first class accommodation, but this was withdrawn in 1940. In the early 1950s, some Uxbridge O and P Stock trains were transferred to the Circle line. The increasingly unreliable metadynes were replaced and the converted trains became known as CO/CP stock. In the early 1960s, the remaining Uxbridg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
British Rail Class 73
The British Rail Class 73 is a British electro-diesel locomotive. The type is unusual in that it can operate from the Southern Region's 650/750 V DC third-rail or an on-board diesel engine to allow it to operate on non-electrified routes. This makes it very versatile, although the diesel engine produces less power than is available from the third-rail supply so the locomotives are rarely operated outside of the former Southern Region of British Rail. Following the withdrawal and scrapping of the more powerful Class 74 electro-diesels in 1977, the Class 73 was unique on the British railway network until the introduction of the Class 88 electro-diesels in 2017. Ten locomotives have been scrapped. History The Southern Railway's expanding third rail electric passenger network (which had begun as far back as 1915) was until 1941 a purely passenger electric multiple unit (EMU) system. This was because it was necessary to have gaps in the third rail for level crossings, etc., w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
British Rail Class 74
The British Rail Class 74 was an electro-diesel locomotive that operated on the Southern Region of British Railways, rebuilt from redundant Class 71 locomotives in the late 1960s. An electro-diesel locomotive is one that can operate either from an electrical supply, such as overhead catenary or (in this case) an energised third rail, or from an onboard diesel engine. All were withdrawn between June 1976 and December 1977, and scrapped between 1977 and 1981. History Twenty-four British Rail Class 71 (pre- TOPS type HA) were built in 1958 at the British Rail works in Doncaster and in 1964 ten were deemed surplus to requirements, withdrawn from service and placed in storage. The Southern Region was highly impressed with the "little-ED" JA & JB/class 73 locomotives and were keen to see a higher power locomotive with the same flexibility. In 1965, discussions were opened with English Electric (builders of the production JB/Class 73) to produce a high powered electro-diesel. Ori ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
British Rail Class 71
The British Rail Class 71 was an electric locomotive used on the Southern Region of British Railways. Unlike Southern Region electro-diesel locomotives (such as classes 73 and 74) they could not operate away from the electrified (750 V DC) system. History As part of the British Transport Commission's Modernisation Plan of 1955, twenty-four electric locomotives were built in 1958 for the Kent Coast main lines. They were built at the British Rail workshops in Doncaster. Numbers were originally E5000–E5023 but the first locomotive, E5000, was renumbered E5024 in December 1962. They were classified type HA under the Southern Region's pre-TOPS scheme. Power supply Power collection was from a 3rd rail at 650V DC (Eastern & Central sections) or 750V DC (Western section) and control was by flywheel booster, as in British Rail Class 70. In some yards (notably Hither Green, South East London and Snowdown colliery near Dover) overhead wiring energised to 650V DC was used. Thi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
British Rail Class 70 (electric)
The British Rail Class 70 was a class of three third rail Co-Co electric locomotives. The initial two were built by the Southern Railway (SR) at Ashford Works in 1940–41 and 1945 and were numbered CC1 and CC2 - the Southern Railway latterly preferring French practice for locomotive numbers which also gave an indication of the wheel arrangement. Electrical equipment was designed by Alfred Raworth and the body and bogies by Oliver Bulleid. CC2 was modified slightly from the original design by C. M. Cock who had succeeded Raworth as Electrical Engineer. The third was built by British Railways in 1948 and numbered 20003. Southern Railway nos. CC1 and CC2 Externally, it was clear that the cab design was greatly influenced by the SR's experience with the 2HAL electric multiple unit (EMU) design. It has even been suggested that this was because the jigs for the welded cabs already existed and thus made for speedy and cheap construction. At the outbreak of war in 1939, most ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
