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Commonly used terms in the Electrical industry.
earth wire
an overhead wire which is maintained at ground potential for purposes of lightning shielding and system grounding.
earthing
See
grounding
electromagnetic smart materials
materials such as shielding materials, radar-absorbing materials (RAMs), and electromagnetic surface materials, in all of which some electromagnetic properties can be adaptively controlled by means of an external stimulus dictated by the sensed electromagnetic response.
electronic motor starter
starter in which solid state devices provide reduced voltage to the motor for starting, thus limiting the starting current.
electroplastic smart material
material with smart properties of elastic deformation changes proportional to a controlled electric current applied in proportion to the sensed deformation.
flat voltage start
the usual initial assumption made when beginning a power-flow study. All voltages are assumed to be 1.0 p.u., and all angles are assumed to be zero.
flowchart
a traditional graphic representation of an algorithm or a program, in using named functional blocks (rectangles), decision evaluators (diamonds), and I/O symbols (paper, disk) interconnected by directional arrows which indicate the flow of processing. Also called flow diagram.
forward converter
an isolated version of a buck converter. The primary and the secondary of the transformer conduct at the same time. The transformer does not store energy. An additional winding with a diode is often used to reset the magnetizing energy when the transistor is off.
four-point starter
a manual motor starter that requires a fourth terminal for the holding coil. Because of its independent holding coil circuit, it is possible to vary the current in the field circuit independently of the holding coil
circuit. The disadvantage is that the motor starter holding relay will not drop out with loss of the field; however, proper overcurrent protection should shut down the motor in the event of field loss.
frequency converter
an equipment or circuit that converts an RF signal to an intermediate (IF) signal in receivers. It converts an IF signal to an RF signal in transmitters.
generator inertia constant
a term proportional to the combined moment of inertia of the turbine-generator mass.
harmonic distortion
caused by the nonlinear transfer characteristics of a device or circuit. When a sinusoidal signal of a single frequency (the fundamental frequency) is applied at the input of a nonlinear circuit, the output contains frequency components that are integer multiples of the fundamental frequency (harmonics). The resulting distortion is called harmonic distortion.
hertz
a unit of frequency.
hot restart
reassumption, without loss, of all operations in the system from the point of detected fault.
inertia constant
the energy stored in an electric machine running at synchronous speed and given in megajoules per megavoltampere of machine rating.
insertion loss
(1) worst-case loss of the device across the stated frequency range. The loss due to the insertion of the unit in series with a signal path.
(2) transmission loss of an RF or microwave component or system, typically measured in decibels.
inverter
switching circuit that converts direct current to alternating current.
An inverter can be classified as a natural-commutation type or a self-commutation type. The output AC of a natural-
commutated inverter is synchronized to the AC line. This type of inverter is a thyristor rectifier in a reversed order. The output AC of a self-commutated inverter is independent, i.e., both the frequency and amplitude may be controlled. Commonly used self-commutated inverters include square-wave inverters and PWM inverters.
irreversible loss a reduction in the magnetization of a permanent magnet that can only be recovered by remagnetizing the material, usually caused by temperature extremes, reversing fields, or mechanical shock.
load-commutated inverter (LCI)
an inverter in which the commutating voltages are supplied by the load circuit.
magnetic motor starter
motor starter that uses electromechanical devices such as contactors and relays.
magnetostrictive smart material
one of a class of materials with self-adaptively modifiable elastic properties in response to a magnetic field applied in proportion to sensed stress-strain information.