Engines - power factor - kVA/kW

[rja211077]

With regard to stationary, industrial type engines, they are rated for their power output in terms of KVA or kW, where kW/KVA is a power factor (PF). I always learnt at school that power was just voltage x current so why the need for this PF? I have also only come across two values for PF - 0.8 and 1. Why are engines made with these two PFs predominantly?

[Viv]

A confusion of terms. KW is simply kilowatts or thousands of watts and watts is a unit of work. An engine can be rated as having a power output in BHP,= brake horse power,= power measured on an engine brake, one horse power is about 770 watts so a 1Kw motor is about 1.3Hp Its fairly interchangeable but KVA is a measure of electrical power input corrected for PF power factor in AC circuits (alternating current). Power factor takes account of the inductive and capacitive nature of electric motors, this means that the current (amps) waveform drawn by the motor can lead or lag the voltage waveform. An easy way to think of it is as a phase angle value. Viv