Dictionary of Electrical Engineering

Commonly used terms in the Electrical industry.

an intentional lowering of utility voltage to reduce loading on the system.
a conductor, usually carbon or a carbon-copper mixture, that makes sliding electrical contact to the rotor of an electrical machine. Brushes are used with sliprings on a synchronous machine to supply the DC field and are used with a commutator on a DC machine.
brush rigging
the components used to hold the brushes of a rotating machine in place, and to insure proper brush tension is applied.
brush tension
the force required on the brushes of a rotating machine to insure proper contact between the brush and the commutator or slipring. Proper brush tension is usually provided by springs, and is specified in the manufacturer's technical manual of the machine.
brushless DC motor

See electronically commutated machine
brushless exciter

See rotating-rectifier exciter
brushless rotary flux compressor
a rotating machine designed to deliver pulsed output (1 MJ in 100 µs). The stator coils are excited by an external capacitor bank. The rotor is a salient structure that compresses the flux resulting in amplification of the electric pulse, by converting the rotating kinetic energy of the rotor to electrical energy.
bulb generator
a free-standing generator contained in a streamlined, waterproof bulb-shaped enclosure and driven by a waterwheel resembling a ship's propeller on a shaft which extends from one end of the enclosure. They are used in tidal power installations.
bulk power
a term inclusive of the generation and transmission portions of the power system.
bulk substation
a substation located on a high-voltage transmission line which supplies bulk power to a non-generating utility.
the practice of paralleling several conductors per phase in an overhead transmission line for the purpose of increasing ampacity and decreasing inductive reactance.
bundle spacer
a rigid structure which is used to maintain the spacing of wires in a bundled conductor on an overhead electric power transmission line.

See bundle
bundled services
utility services which are sold together, like power transmission and distribution services in non-deregulated electric utilities.
breakage of an overhead electric power line due to heating from excess current.
a measure (e.g., megawattt-days / ton) of the amount of energy extracted from each unit of fissile material invested in a nuclear reactor.
(1) a data path connecting the different subsystems or modules within a computer system. A computer system will usually have more than one bus; each bus will be customized to fit the data transfer needs between the modules that it connects.
(2) a conducting system or supply point, usually of large capacity. May be composed of one or more conductors, which may be wires, cables, or metal bars (busbars).
(3) a node in a power system problem
(4) a heavy conductor, typically used with generating and substation equipment.
bus admittance matrix

See Y-bus
bus differential relay
a differential relay specifically designed to protect high power buses with multiple inputs.
bus impedance matrix

See Z-bus
a rigid, hollow cylindrical insulator which surrounds a conductor and which extends through a metal plate such as a the wall of a transformer tank so as to insulate the conductor from the wall.