How To Calculate Overload Protection For 3 Phase Motors. Divide by the rated full load current from the motor nameplate. If the motor current is 22a and the rated full load current is 20a, then the load factor is 22/20 = 1.1.
Motor overload protection is necessary to protect the motor and to help ensure the motor performs as expected. Separate motor overload protection shall be based on the motor nameplate current rating. If these figures don't match, then measuring the motor current may not give a true indication of motor heating and overload.