The percentage of the motor output power P2 to the motor input power P1 is called the electric motor efficiency. With the letter “η”. Namely: ETA = (P2/P1 * 100%).
Asynchronous motor efficiency is generally 75%-92%, there are many factors affecting motor efficiency, the root cause is its internal loss: efficiency = input power loss power / input power.
The efficiency of the motor and drive the load, the speed of the motor, the motor type and power supply voltage are related. The load is small low efficiency, large load high efficiency; reduce the speed of the motor, in most cases, the efficiency is lower; the power supply voltage is higher or lower than the motor rated voltage, increase the iron loss and copper (loss of motor under the full load condition), thus reducing efficiency; large capacity motor winding and deep slot motor efficiency is low.