Electrical Engineers and Master Electricians (EEAME) Portal

Dictionary of Electrical Engineering

Commonly used terms in the Electrical industry.

an arrangement of one or more magnets to form a magnet system that produces a magnetic field with one pair of opposite poles.

magnetic monopole

a magnet system that produces a magnetic field of a single polarity. Although nonexistent, may be approximated by one pole of a very long magnet.

pole

one end of a magnet or electromagnet in electrical machines, created by the flux of the machine.

pole line

any power line which is carried overhead on utility poles.

pole pitch

the angular distance (normally in electrical degrees) between the axes of two poles in an electrical machine.

pole top pin

a steel pin onto which a pin insulator is screwed.

pole-top transformer

generally a distribution transformer which is mounted atop a utility pole near the customer.

salient-pole drive

See synchronous drive

salient-pole rotormachine

AC motor/generator design in which the rotor is constructed of outward-projecting pole pieces mounted on a shaft-mounted central spider assembly. Spider assemblies are typically spoked. Pole pieces are built up from laminated sheets, which are bolted together between a pole shoe on the outer end and dovetail fixture on the inner end. The dovetails are keyed into slots on the spider to mount the pole pieces to the rotor. Rotor windings are generally constructed from preformed, insulated coils that are fit over the pole pieces during assembly. Salient rotors are typically low-speed designs with short axial length and large diameter.

shaded-pole motor

a single-phase induction type motor that uses shaded poles on the stator to create a weak quasi-rotating magnetic field. Shaded-pole motors are only built in small fractional horsepower sizes and produce a very low starting torque that is suitable only for fan-type loads. See also shaded pole.

single-pole reclosing

the practice of clearing a fault which appears on one phase of a three-phase electric power line by disconnecting and reclosing only that phase as opposed to opening and reclosing all three phase conductors.

single-pole double-throw (SPDT)

a switch that has a common port and two output ports. Among these two ports, only one selected port can be connected to the common port.

single-pole single-throw (SPST)

a switch that has a pair of input-output ports. By changing its status, the switch works as short or open circuit.

written-pole motor

a single-phase motor that uses a coil to write poles on the magnetic rotor. The advantage of the written-pole motor is that it draws much lower starting current, allowing much larger single-phase motors. The development of this motor has been sponsored by the Electric Power Research Institute.