Most electric motors are designed to run at 50% to 100% of rated load. Maximum efficiency is usually near 75% of rated load. Thus, a 10-horsepower (hp) motor has an acceptable load range of 5 to 10 hp; peak efficiency is at 7.5 hp. A motor's efficiency tends to decrease dramatically below about 50
Efficiency is the ratio of mechanical energy output divided by the electrical energy input. ... These values are intended to represent the lowest point in the bell curve of motorefficiency distribution. - Apparent Efficiency. This is the product of a motor's efficiency and power factor.
This efficiency depends on frequency of the voltage supplied to the motor and on electrical power. Results of laboratory testing of the motor's efficiency are presented. Most pump drives employ squirrel-cage induction motors whose rated efficiency ηsn at power of above 2kW, are most often greater