POWER FACTOR

Power Factor is the ratio of true power or watts to apparent power or volts amps. They are identical only when current and voltage are in phase than the power factor is 1.0 The power in an Ac circuit is very seldom equal equal to the direct product of volts and amperes. In order to find the power of a single phase ac circuit the products of volts and amperes mus be multiplied by the power factor. Low power factor is usually not that much of a problem in residential homes.

The angle of this power triangle graphically indicates the ratio between the amount of dissipated power and the amount absorbed/returned power. It also happens to be the same angle  as that of the circuit's impedance in polar form.

A low power factor is the result of inductive loads such as transformers and electric motors. Unlike resistive loads creating heat by consuming kilowatts, inductive loads require a current flow to create magnetic field to produce the desired work.




LEADING and LAGGING power factors

• Inductive loads - transformers, motors and wound coils - consumes reactive power with current waveform lagging the voltage.
• Capacitive loads - capacitor banks or buried cables - generates reactive power with current phase leading the voltage.