What size motor overloads to put on a 3 phase motor.i how to go about to calculate this. its a 5 HP Motor208-230 volt12.9amp at 208SF1.25 SFA 16.1. the motor is a outdoor motor replacing and old o?

Answer 1

5 HP is equal to 3.7 KW. 415 Volts 3 phase 50 hz system takes 6.29 amps. Same 3.7 KW motor with 230 volts, single phase 50 hz takes 18.9 amps. Same 3.7 kw motor with 230 volts three phase 50 Hz takes 11.1 amps. These are full load current with 0.85 assumed power factor.

To arrive at over load, you may 5 to10% over load and set the over load setting.