Explanation of Power Factor Meter

Power Factor Meter

The power factor of an A.C circuit can be calculated from the following relation by measuring the current, voltage and power. I.e. cosΦ = P/VI.

This method of determining the power factor of an electrical A.C circuit, is however, of low accuracy has a number of draw backs. Hence, it is desirable to have an instantaneous indication of the power factor of an A.C circuit, especially where it is varying continuously.

Therefore, a power factor meter is connected in the A.C circuit to measure power factor which indicate directly by a single reading.

There are two types of power factor meters:

1.       Electrodynamometer type of p.f meters

               (a)     Single phase 

               (b)     Three phase

2.       Moving iron type p.f meters

               (a)     Single phase

               (b)     Three phase

Let us confine our attention only on 1Φ, dynamometer type P.F meter as per the syllabus concern.