Positive Wire, or Conductor. The wire, or conductor, connected with the positive pole of any apparatus which produces electro-motive force.

Potential, Electric. The power to perform electric work.

Potential Energy. Capacity for doing work. Potential energy when liberated becomes actual energy for the performance of work.

Power-generator. Any source from which power is generated.

Power-house. A station in which the plant of an electric power system is operated and the current distributed to local or long-distance points. Power-houses are either primary or secondary stations. In the primary station the current is generated directly by the aid of mechanical power, either the steam-engine or the steam-turbine. The secondary station, or sub-station, is located at a distance from the main power-house, and has no mechanical means of generating current. The current, usually of high alternating voltage, is supplied to the sub-station from the main power-house; and by means of transformers and converters, the high-voltage current is transformed into one of lower E-M-F and higher amperage, for distribution over local lines.

Power-unit. The unit of electric power is the volt-ampere or watt.

Pressure, Electric. Electro-motive force or voltage.

Primary. A term used to designate the induction-coil in an induction-apparatus or transformer. It is an abbreviation for primary coil.

Primary Battery. (See [Battery, Primary].)

Prime Conductor. (See [Conductor, Prime].)