# Re: Will there be any change in capacity rating of a 3 phase 750 KW generator if to change from 440 VAC to 230 VAC?

Home Electrical Engineering Forum General Discussion Will there be any change in capacity rating of a 3 phase 750 KW generator if to change from 440 VAC to 230 VAC? Re: Will there be any change in capacity rating of a 3 phase 750 KW generator if to change from 440 VAC to 230 VAC?

#13325
Spir Georges GHALI
Participant

@guest said:
Will there be any change in capacity rating of a 3 phase 750 KW generator if to change from 440 VAC to 230 VAC?

Dear ;

First, the Power’s unit of any source ” Transformer, Generator, … ” is given in ” Apparent power – S ” and the unit is ” kVA “

Even that your question is not too clear, I will try to clarify that point as follow :

Assume that we have 2 sources with the same rating power of each one ” 200 kVA “, but the output voltage is different where that’s ” 400V – 3 phase ” for the 1st and ” 230V – 3 phases ” for the 2nd, and as the Power is the multiplication of the Voltage value by the current value, and the Power for both are the same, in this case the ” Nominal Current – In  will be different that can be calculated as following :

S = 1.732 x Uo x In            In = S / 1.732 x Uo

so, the Nominal Currents are :

for the 1st source :

In(1) = 200 x 1000 / 1.732 x 400 ≈ 289 A

for the 2nd source :

In(2) = 200 x 1000 / 1.732 x 230 ≈ 502 A