What is Power Factor?
Power factor is defined as the percentage ratio between the true power, measured in kilowatts (kW), and apparent power, measured in kilovolt amperes (kVA). The apparent power is the total requirement that a facility places upon the electric utility to deliver voltage and current, without regard for whether or not it does actual work. Electric utilities typically charge customers a higher rate when power factor falls below a certain level — often 90%.
You calculate power factor as follows:
True power (kW) ÷ apparent power (kVA) = power factor
Here’s an example of a good power factor value at a facility:
50kW ÷ 52kVA = 0.96 (a good power factor of 96%)
Now, here’s an example of a poor power factor value at a facility:
50kW ÷ 63kVA = 0.79 (a poor power factor of 79%)
taken from EC&M - http://ecmweb.com/weeblylink_new_window