What is the efficiency of asynchronous motor

The ratio of output power to input power of asynchronous motor. Usually expressed as a percentage.

The efficiency of asynchronous motor is generally 75% – 92%. There are many factors that affect the efficiency of motor, and the fundamental reason is its internal loss: efficiency = (input power – loss power) / input power.

The efficiency of asynchronous motor also varies with the load. When the load is 0.7-1 times of the rated load, the efficiency is the highest and the operation is the most economical.

What are the equivalent circuits of asynchronous motor


1. Neglecting the harmonics of space and time

2. Neglect magnetic fullness

3. Careless iron loss

In electrical engineering, the quantity of rotor side is converted to that of stator side. The conversion criterion is to insist that the air gap flux of the motor remains unchanged, but this method is not the only one. For example, it is converted according to the criterion of stator total flux stability and the criterion of rotor total flux stability. It is of primary significance to convert the rotor flux according to the criterion of rotor total flux stability.

The figure below shows the general steady-state equivalent circuit

Steady state equivalent circuit of induction motor with time delay

The excitation circuit represents the air gap flux linkage of the motor, and its circuit is the equivalent circuit in electromotology

The “T-1” type equivalent circuit excitation circuit of outstanding rotor flux represents the total rotor flux, which is used to analyze the conservation of rotor flux. The circuit and vector diagram are as follows

The phasor diagram of “T-1” type equivalent circuit is as follows

Editor in charge: yyx

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