3 phase current calculation

[jgreen]

Can someone please help me with the correct current calculation? I have equipment that is 3 phase 220VAC, 3000W. I calculated the current draw to be 3000/(220*1.73)=7.88A. The manufacturer however states this is incorrect...find the resistance first (220*220)/3000=16.33 and then divide to get the current.... I=220/16.33=13.42A. Which is right (&why)? Thanks for any help!

 

[coulter]

Re: 3 phase current calculation

Your first answer is three phase - which is what you want. Your second answer is single phase - just forgot to divide by sqrt(3) - do that and it should be the same as the first.

I don't know why the mfg would insist on the second method. It is the same as the first, just a few more steps through Ohms Law.

carl

[ November 14, 2004, 06:18 PM: Message edited by: coulter ]