# Apparent Power



## Sharon (Sep 30, 2010)

* It's amazing the effect intense studying has on your brain. Now I am tripping up on something which I'm sure is very simple - the equation for apparent power. *

S=VI* or S=VICos(theta) or S=sqrt(3)VICos(theta)

How do I know when to use which equation?

Thanks....Sharon :tardbang:


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## Flyer_PE (Sep 30, 2010)

Here are the equations:

Apparent Power for a single phase system: S = VI*

Apparent power for a three-phase system: S = (sqrt3)VI*

Real Power (Watts): P = S cos(theta)

Reactive Power (VAR): Q = S sin(theta)


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## Sharon (Sep 30, 2010)

Flyer_PE said:


> Here are the equations:
> Apparent Power for a single phase system: S = VI*
> 
> Apparent power for a three-phase system: S = (sqrt3)VI*
> ...


* Thank You!....Sharon*


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