Electrical Power Factor

Introduction to electrical power factor:

In a electrical circuit, the power consumed by a load is the product of the voltage across the load and the current passes through the load. But in AC circuits, the voltage and current are in different electrical angles if the load is inductive or capacitive. Is this topic Electric Field Lines hard for you? Watch out for my coming posts.

Therefore, at any point of time, the power consumed by the circuit is the product of the voltage component projected in line with the current direction and the actual current.

The voltage component projected in line with the current direction is the magnitude of the voltage times the cosine of the electrical angle between the voltage and current. The Cosine of this angle is defined as power factor of the load.

Description of Electrical Power Factor

Referring to the above vector diagram, the dot product of V and I (the energy and in turn the power is the dot product of vectors) gives the power P, which is given by,

P = VI cosФ

or P = VI (power factor of the load)

In case of inductive load, the current lags the voltage and in case of capacitive loads the current leads the voltage. This is the reason why the inductive loads are said to have lagging power factors and the capacitive loads are with leading power factors. In case of resistive loads, the angle between the voltage and current is 0. That means the power factor is 1(called as unity power factor). Understanding coulomb's law equation is always challenging for me but thanks to all math help websites to help me out.

Effect of Electrical Power Factor:

We have seen that the power consumed by an inductive load is VI times the power factor or VI times the Cosine of the angle of lag. Since the Cosine of any angle is always less than 1, the power consumed by an inductive load is always less than the power consumed by a resistive load drawing the same current.

Thus, the conductors carry a larger current for a given power in case of lagging power factor.