Feeder calc for 480/120/240 motors

[frenchy]

I was wondering how you would calc. the secondary side of this?
Give the feeder size in amps, using an inverse time CB for 3-480v 3ph motors, 1-7.5hp240, 2-2hp120, 1-1hp120, would I add 250% to the largest plus the others or 125% plus the others,for the 120/240 feeder.Then add to the 480v load. Thanks for the look, frenchy

 

[kiloamp7]

Re: Feeder calc for 480/120/240 motors

Not sure I fully understand the question. But generally, if you are trying to find the minimum feeder for mixed loads of different voltages, quantity of phases, etc., first convert all to a common value.

That common value is VA. VA is VA is VA.

 

[rjdad82]

Re: Feeder calc for 480/120/240 motors

A little bit confused frenchy, to many missing links. Are they ac motors>? Do you have separate panels for the high and low voltage.? A couple suggestive places to look that might help: 430.24 for several motors, 430.110(3), 220.10 and 220.30. sorry couldn't be more help.

 

[frenchy]

Re: Feeder calc for 480/120/240 motors

Originally posted by rjdad82:
A little bit confused frenchy, to many missing links. Are they ac motors>? Do you have separate panels for the high and low voltage.? A couple suggestive places to look that might help: 430.24 for several motors, 430.110(3), 220.10 and 220.30. sorry couldn't be more help.

Thanks, I did get my answer today.
frenchy