Power Supply Calculations 1

[Camomac]

Hi,

If you have a Power supply, that supplies a load of 15Amps at 13.8VDC, how would you calculate the current on the AC side of the supply (@240V). (this information could help with circuit breaker sizing etc?)

If you have to assume an efficiency for the power supply and a input power factor, lets say 90% efficiency and 0.95 pf.

Thankyou

 

[IRstuff]

OK, so apply conservation of energy. Don't forget to include a power factor correction, though...

TTFN
faq731-376

 

[MacGyverS2000]

How is it possible a practicing engineer (or even a first-year EE student) could ask such a basic question?

Dan - Owner

http://www.Hi-TecDesigns.com

 

[Camomac]

Hi,

15Amps at 13.8VDC = 207W

90% efficiency....power on AC side = 230W

P = V*I*pf
230 = 240*I*0.95

I = 1.009A???

Would this we the correct answer?

Sorry Macgyver, this was a discussion I was having with a friend and thought we would get a confirmation.

Thankyou for your responses

 

[fahad8413]

Hello all,

@Camomac, you got it right in the calculation. However, it holds good only for a 1-Ph system as the input. For a 3-Ph system, dont forget to add "Root 3" to the formula.

Fahad Shaikh