Power Factor - The Basics
Power Factor – The Basics (photo credit:

What is Power Factor?

Super. I’m ready to find out what power factor is. To understand power factor, we’ll first start with the definition of some basic terms:

  • KW is Working Power (also called Actual Power or Active Power or Real Power).
    It is the power that actually powers the equipment and performs useful work.
  • KVAR is Reactive Power.
    It is the power that magnetic equipment (transformer, motor and relay) needs to produce the magnetizing flux. KVA is Apparent Power. It is the “vectorial summation” of KVAR and KW.
Let’s look at a simple analogy in order to better understand these terms…. Let’s say you are at the ballpark and it is a really hot day. You order up a mug of your favorite brewsky. The thirst-quenching portion of your beer is represented by KW (Figure 1). Unfortunately, life isn’t perfect. Along with your ale comes a little bit of foam. (And let’s face it…that foam just doesn’t quench your thirst.) This foam is represented by KVAR.

The total contents of your mug, KVA, is this summation of KW (the beer) and KVAR (the foam).

Power factor - the basics questions

So, now that we understand some basic terms, we are ready to learn about power factor!

Title:Power Factor – The Basics
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Power Factor - The Basics
Power Factor – The Basics

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  1. Dang Luan
    Jun 02, 2016

    Loss reduction = 1- (0.65^2/1^2) ?, who explain?

  2. Khaled
    Apr 11, 2016

    Thank you for the great guide, but may be there is a mistake in the example (page 10), the load is a fan with 250 HP, with PF of 65%

    Then it was given that KVA is 250, KW is 163, how come?

    ain’t 1 HP = 746 watt ???

    Jan 29, 2014


    • jim
      Nov 12, 2015

      nope. KVA = sqaure root of (KW)^2 + (KVAR)^2

  4. Pankajjyoti
    Jul 23, 2013

    Sir, this site is very much helpful for students. But there is no technical articles related to Power electronics or Control System (except automation part).It will be a great thing if the above topics are also added

  5. […] made up of:A transformer supplying power,Linear loads,Non-linear loads causing harmonic currents,Power factor correction capacitors.Simplified diagram of installation of power transformer, linear and non […]

  6. mpriya
    Feb 28, 2013

    Hi Can you please forward me the 13 pages of the power factor,because I am been blocked from our administrator.

    Thank you

  7. Pieter@1
    Jan 31, 2013

    Power Factor – The Basics

    Hi Can you please forward me the 13 pages of the power factor,because I am been blocked from our administrator.

    Thank you

    Nov 30, 2012

    great example to understand.

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