I was asked to give an estimated running cost of operating a 3 phase 75 HP motor for 80 hrs. I assumed at 480 Vac that the motor would have roughly 100 FLA.

My equation then became KW = 480 V * 100 A * 1.732 / 1000 (ignored power factor and demand) and came to roughly 83 KW.

I had a coworker check to verify my answer and he used a different method. He used 1 HP = .746 KW and came to roughly 56 KW. Does motor phase affect this equation?

Which method is correct when solving for KW in a three phase system and why?

Any insight would be apprecciated, Thanks.

## Bookmarks