Power And Power Factor

POWER AND POWER FACTOR

Power

The average power in an alternating circuit is given by:

P = VI cos ᴓ watts.

The power triangle shows three types of power.

1) Apparent power

2) Real power

3) Reactive power.

Apparent Power (S):

It is defined as the product of rms value of voltage current. It is denoted by S.

S = VI VA.

It is measured in Volt-Amp (VA).

Real Power (or) True Power (or) Active Power (P):

It is defined as the product of the applied voltage and the active component of the current.

P=VI cos θ watts.

It is measured in watts.

Reactive Power (Q):

It is defined as the product of the applied voltage and the reactive component of the current.

It is measured in volt amp reactive.

Power Factor

It is defined as the factor by which the apparent power must be multiplied in order to

It is the ratio of true power to apparent power.

Power Factor = True Power / Apparent Power

The nature of power factor depends by the position of current with respect to the voltage.

If the current follows the voltage the power factor is unity.

If the current lags voltage the power factor is said to be lagging.

If the current leads the voltage the power factor is said to be leading.