As the most commonly used power equipment in industrial automation and mechanical equipment, the safe operation and life of induction motors are directly affected by temperature control. During the operation of the motor, the temperature rise of the winding and the core is one of the important indicators to measure whether the motor is overloaded or faulty. Reasonable temperature rise limit standards not only ensure the stability of motor performance, but also effectively extend the service life of the equipment.
This article will introduce in detail the definition of induction motor temperature rise, relevant standards and precautions in practical applications, to help engineers and equipment managers scientifically control motor temperature and improve operational reliability.
The meaning and importance of induction motor temperature rise
Temperature rise refers to the value of the motor winding or other component temperature exceeding the ambient temperature after the motor runs for a certain period of time under rated load. Usually, temperature rise is divided into winding temperature rise and casing temperature rise. The winding temperature rise has the greatest impact on the insulation system and is a key parameter for motor design and operation control.
Excessive temperature rise will accelerate insulation aging, reduce motor efficiency, and even cause equipment failure and safety hazards. Therefore, a reasonable limit on temperature rise is the basis for ensuring the safe, stable and long-life operation of induction motors.
International and national standards for induction motor temperature rise limits
Regarding the standards for induction motor temperature rise, the international standards are mainly based on IEC 60034-1 “Rotating Motors Part 1: Ratings and Performance”, which clearly stipulates the temperature rise of motors.
Domestically, specific requirements for temperature rise limits are put forward based on GB/T 755-2008 “Rotating Motor Ratings and Performance” and related industry standards.
Generally speaking, the allowable winding temperature rise limits of induction motors with different insulation levels are as follows:
Class A insulation: temperature rise limit is about 105°C
Class E insulation: temperature rise limit is about 120°C
Class B insulation: temperature rise limit is about 130°C
Class F insulation: temperature rise limit is about 155°C
Class H insulation: temperature rise limit is about 180°C
The temperature rise here refers to the value of the winding temperature exceeding the ambient temperature, which is usually calculated as 40°C.
A high insulation level means that the motor can withstand higher temperatures, but the cost and manufacturing process are usually more complicated.
How to measure and evaluate temperature rise?
Temperature rise test usually adopts thermal balance method, that is, let the motor run continuously under rated load until the temperature reaches a stable state, and then measure the winding and housing temperature.
Common temperature measurement methods include thermocouple measurement, infrared temperature measurement and winding impedance method. Correct temperature rise measurement is an important link to ensure compliance with standards.
The importance of temperature rise control in practical applications
Reasonable control of induction motor temperature rise can bring many advantages:
Extend motor life
Excessive temperature will accelerate the aging of insulation materials, and controlling temperature rise can effectively extend the service life of the motor.
Improve operating efficiency
When the temperature is suitable, the motor resistance is low, energy consumption is reduced, and efficiency is improved.
Ensure equipment safety
Avoid insulation damage and mechanical damage caused by overheating, and reduce the risk of fault downtime.
Save maintenance costs
Reduce the need for frequent maintenance and replacement of parts, and save enterprise operating costs.
The temperature rise limit of induction motor is a key parameter to measure the safety and performance of motor operation. Complying with IEC and relevant national standards, combined with scientific measurement and monitoring, can effectively prevent motor overheating damage and extend equipment life.
When selecting and using induction motors, enterprises should pay attention to the insulation level and temperature rise performance of the products. At the same time, they should be equipped with intelligent monitoring systems to grasp the motor temperature in real time, take prevention as the priority, and ensure the continuous and stable operation of the equipment.
If you want to learn more about the temperature rise related technologies of induction motors or purchase suitable products, please contact us. We will provide you with professional support and customized solutions.