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Class Photograph Manufacturer/Year Number Status Withdrawn Power Voltage Notes Class 11: BN/ACEC (1985-1986) 12 Withdrawn 2013 3130 kW (4200 hp) 3000 V DC, 1500 V DC Class 12: BN/ACEC (1986-1987) 12 In service outside Belgium 2010 3130 kW (4200 hp) 25 kV AC, 3000 V DC Class 13: Alstom (1997-2001) 60 In Service n/a 5200 kW (6975 hp) 25 kV AC ...
A schematic representation of long distance electric power transmission. From left to right: G=generator, U=step-up transformer, V=voltage at beginning of transmission line, Pt=power entering transmission line, I=current in wires, R=total resistance in wires, Pw=power lost in transmission line, Pe=power reaching the end of the transmission line, D=step-down transformer, C=consumers.
The AC current density J in a conductor decreases exponentially from its value at the surface J S according to the depth d from the surface, as follows: [4]: 362 = (+) / where is called the skin depth which is defined as the depth below the surface of the conductor at which the current density has fallen to 1/e (about 0.37) of J S.
A power converter is an electrical device for converting electrical energy between alternating current (AC) and direct current (DC). It can also change the voltage or frequency of the current. Power converters include simple devices such as transformers , and more complex ones like resonant converters .
Angle notation can easily describe leading and lagging current: . [1] In this equation, the value of theta is the important factor for leading and lagging current. As mentioned in the introduction above, leading or lagging current represents a time shift between the current and voltage sine curves, which is represented by the angle by which the curve is ahead or behind of where it would be ...
In an alternating current (AC) electric power system, synchronization is the process of matching the frequency, phase and voltage of a generator or other source to an electrical grid in order to transfer power. If two unconnected segments of a grid are to be connected to each other, they cannot safely exchange AC power until they are synchronized.
On 12 April 2018, the police said that Rakesh Kumar, who leaked the class 12 economics paper, had leaked class 10 mathematics paper also. [40] Consequently, the Central Board of Secondary Education has put in place a system of "encrypted" question papers, which are supposed to be printed by the schools half an hour before the exam starts. [41]
In alternating current (AC) systems, the movement of electric charge periodically reverses direction. AC is the form of electric power most commonly delivered to businesses and residences. The usual waveform of an AC power circuit is a sine wave , though certain applications use alternative waveforms, such as triangular or square waves .