A 120-V motor has mechanical power output of 2.20 hp. It is 92.0% efficient in converting power that it takes in by electrical transmission into mechanical power.

Question

A 120-V motor has mechanical power output of 2.20 hp. It is 92.0% efficient in converting power that it takes in by electrical transmission into mechanical power.
(a) Find the current in the motor.

Henry · Answer

Po = 2.20hp * 746w./hp = 1641.2 Watts Pi = Po/0.92 = 1641.2/0.92 = 1784 Watts Pi = 120*I = 1784 W. I = 1784/120 = 14.9A.