UPS output calculation

Thread Starter

shahnawaz

Joined Dec 30, 2008
37
Hi all,

i am cofuse about the calculation of Output of my UPS with cosθ of my UPS.
my ups is 6KVA at 230VAC. so my boss is calculating the cosθ as below

P= VI Cosθ
6000= 230 X I X .8
6000/230 X .8 = I
6000/184 = I
I= 32.60.
but i am saying as read is
6000 X 0.8/230 = 20.8

PLEASE TELL ME WHY THE HUGE DIFFERENCE BETWEEN MY AND MY BOSS CALCULATION.

Please tell me in detail of how i can calculate my output power in amperes and what is the farmula.

thanks
 

#12

Joined Nov 30, 2010
18,224
You're going at it wrong. The power factor does not change the amps that will be provided. It changes the actual power that the load absorbs when the full amperage is flowing. Power = EI cos theta
not I = power/E cos theta
 

t_n_k

Joined Mar 6, 2009
5,455
Yes indeed. The UPS will be capable of delivering a maximum load current of around 26.1A.

A supplementary question might for instance be - Could this UPS service a predicted power load of 4kW at pf=0.6?
 
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