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Nidal
Active Contributor

Join Date: Jul 2008
Posts: 12

how can calc

02/25/2009 7:19 AM

HI

i need to know

how can i calc. trnasformer capacity 20kvto 400v

if i have FLA , RLA , and starting ampe
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Electron Plumber
Associate

Join Date: Feb 2009
Location: Bluegrass Country of Kentucky
Posts: 29
Good Answers: 1
#1

Re: how can calc

02/25/2009 9:37 AM

In the US, you need to use the FLA (full Load Amps) to size the transformer. It needs to be a minimum of 125% of the FLA of the largest motor, plus all the other motor FLAs added up. Then KVA is just Volts X Amps X square root of 3 for three phase circuits. Keep in mind, 125% is just for the US under the NEC. Other countries may have a different approach.

__________________
 Joe the Electrical Contractor to the EOR, I know it was suppose to be in my base bid, but I still am going to submit a change order for it.
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Nidal
Active Contributor

Join Date: Jul 2008
Posts: 12
#2
In reply to #1

Re: how can calc

02/26/2009 5:06 AM

Thanks so much
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