Classification of motor insulation levels

Classification of motor insulation levels

The classification of motor insulation levels is mainly based on the heat resistance of insulation materials, divided into the following five levels, and includes other supplementary explanations:

Main insulation level classification

A-level

The maximum allowable working temperature is 105 ℃, suitable for motors in general environments.

class e

The maximum allowable working temperature is 125 ℃, which can withstand moderate temperature environments and is suitable for ordinary industrial motors.

Grade B

The maximum allowable working temperature is 130 ℃, with strong high-temperature resistance, suitable for high-temperature environments such as metallurgy, chemical industry, etc.

Grade F

The maximum allowable working temperature is 155 ℃, suitable for high temperature and high pressure scenarios, such as power equipment.

class h

The maximum allowable working temperature is 180 ℃, with the best high-temperature resistance performance, suitable for special environments such as high-temperature workshops and nuclear power plants.

Supplementary explanation

Composition of insulation level

The insulation level consists of letters (A-E, F-H) and numbers (such as B120 for B-level insulation, temperature resistance of 120 ℃), with the number representing the allowable temperature rise limit (K value).

Other levels

N-level: The lowest insulation level, suitable for equipment with low insulation requirements such as permanent magnet synchronous motors.

R-grade: High temperature insulation grade, with a temperature resistance of over 200 ℃, suitable for extreme environments.

Application scenarios

The motor needs to select the corresponding insulation level according to the working environment temperature and voltage level, for example:

Household motors (such as washing machines, refrigerators): Class E or Class B;

Industrial motors (such as machine tools, cranes): Class B or Class F;

Special environment (such as high temperature, high humidity): H-grade or R-grade.

Summary

The insulation level of the motor is a key indicator to ensure the safe operation of the equipment, and the appropriate level should be selected according to the actual working conditions. High temperature environments can accelerate insulation aging. It is recommended to regularly test insulation performance to avoid faults caused by overheating.