# Understanding Power Factor Using a Horse and a Railcar

- Link: https://studyelectrical.com/2016/06/understanding-power-factor-using-horse.html
- Published: 2016-06-27T18:59:00+00:00
- Author: 

A simple analogy is the best way to understand power factor. Please read [what is power factor](http://www.studyelectrical.com/2016/07/what-is-power-factor.html)
before reading this article. Beer mug analogy is already explained [here](http://www.studyelectrical.com/2016/07/what-is-power-factor.html).

In the figure, a horse is pulling a railroad car down a railroad track. The railroad
tire are uneven, so the horse must pull the car from the side of the track. The 
horse is pulling the railroad car at an angle to the direction of the car’s travel.

 

[⌊IMG 20160724 224403⌉⌊IMG 20160724 224403⌉[

 * The power required to move the car down the track is the working Of real power(
   kW). The effort of the horse is the total or apparent power (kVA).

 

 * Due to the angle of the horse’s pull, not all of its effort is used to move the
   car down the track.The car will not move sideways, therefore, the sideways pull
   of the horse is wasted effort — the nonworking or reactive power (kVAr).

 

 * The angle of the horse’s pull is related to power factor, which is defined as
   the ratio of real power to apparent (total) power.

 

If the horse is led closer to the center of the track, the angle of side pull decreases
and the real power approaches the value of the apparent power. Therefore, the ratio
of real power to apparent power (the power factor) approaches one. As the power 
factor approaches one, the reactive (nonworking) power approaches zero.

 

In the ideal horse pulling the railcar analogy, if the reactive power (kVAr) is 
near zero, then real power (kW) and apparent power (kVA) would almost be equal, 
which means the horse would not waste as much energy pulling the car. The angle 
formed between real and apparent power would approach zero. The cosine of the angle
would then approach one, resulting in a power factor that approaches one.

 

The closer a system’s power factor is to one, the more efficient the system is.

### The Power Triangle

[⌊Reactive Power Triangle⌉⌊Reactive Power Triangle⌉[One way to illustrate the relationship
between real power, apparent power, reactive power, and power factor is with a power
triangle. As seen, only 70% of the current provided by electric utilities is being
used to produce work.

 

_For example_. using the power triangle illustrated. if Real power = 100 kW and 
Apparent power = 142 kVA 

 

then _Power Factor = 100/142 = 0.70 or 70%._

 

_ _

 

This indicates that only 70% of the current provided by the electrical utility is
being used to produce useful work.

### Related posts:

No related posts.