Dictionary of Electrical Engineering

Commonly used terms in the Electrical industry.

voltage unit
a protective unit (in protective relaying) whose operation depends exclusively on the magnitude of voltage.
voltage variation
long duration a change of voltage RMS value from nominal for a time period greater than 1 minute, and can be used with the words showing a magnitude change such as overvoltage, or under-voltage.
voltage variation
in short duration a change of the voltage RMS value from nominal for a time period from 0.5 cycles to 1 minute, and can be used with the words sag, swell, and interruption for magnitude changes, and the words instantaneous, momentary, of temporary for showing duration.
voltage-behind-reactance model
a representation of a machine in which the stator voltage equations are modeled as a voltage source in series with a reactance (and typically a resistance). The voltage source represents the back emf present on the stator windings due to the coupling between the stator and rotor circuits. In synchronous machine modeling, several different voltage-behindreactance models have historically been used, wherein approximations are used to represent the machine in various detail.
voltage-controlled bus
in power-flow analysis of an electric power system, a bus at which the real power, voltage magnitude, and limits on reactive power are specified. A bus connected to a generator will be so represented.
voltmeter
an instrument for measuring a potential difference between different points of an electrical circuit. Units are volts.
volts/hertz control
a method of speed control of induction machines, used below rated speed. When the volts/hertz ratio is kept constant, the current through the stator windings remains almost the same, except for very low speeds; hence, the available torque remains constant, but the speed changes due to change in frequency.
Powered by The Filipino Engineer