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	Subject - Need help with a generator CGET Howdy, I need help with a 3 phase generator. I help calculating the current output of a generator. I am an electronics tech and if this thing was single phase I wouldn't be here. I have a 15 kW genset. We use it for emergency backup power for a communications center. The building is fed with 120/208 VAC 3 phase. This is what the output of the generator is set for. Can anyone tell me what the amp output would be? Thank you. J.R. lctrc789 Cget, you have about 70 amps you could use on that generator for output power. CGET lctrc789, Thank you for your reply. Could you please post the formula for calculating 3 phase power? Just want to expand on my knowledge of power systems. CGET Also, is that 70 amps per phase to neutral or what? I am real good with single phase circuits but 3 phase is a little puzzling. lctrc789 Cget, I am sorry I didn 't read the question properly at all. 3 Phase power = 41 amps per phase for this generator. Just like a single phase 100 amp panel has 100 amps per pole or side this generator will have about 41. 6 amps per side or pole maximum.. To get this answer for three phase is as simple as single phase to get amperage in single phase you divide wattage (15000) by the voltage in this case 15 KW or 15000 watts divided by 240 would be 62.5 amps if it were single phase.... Now this is 3 phase and you get the answer by taking the KW divided by the voltage and then dividing by the sq root of 3 or 1.732 in 3 phase.... So the answer is 15 KW or 15000 watts divided by 208 (voltage) =72 ammps then divided by the square root of three for three phase. 72.1 amps divided by 1.732 you get 41.6 amps Maximum... Basically three phase calculations are done the same as single phase calculations except the sq. root of 3 is always used. I hope this has helped you in some way. CGET Thank you very much Pat. You have been a big help.