Considering the ambient temperature of 40°C, the maximum operating temperature of the motor cannot exceed 120/130°C. The maximum bearing temperature is 95°C. Relevant standard requirements are as follows.

1. GB3215-82

4.4.1  During split case pump operation, the maximum temperature of the bearings should not exceed 80°C.

2. JB/T5294-91

3.2.9.2  The temperature rise of the bearing shall not exceed the ambient temperature by 40°C, and the maximum temperature shall not exceed 80°C.

3. JB/T6439-92

4.3.3  When the split case pump is running under the specified working conditions, the temperature of the outer surface of the built-in bearing should not be higher than the temperature of the conveying medium by 20°C, and the maximum temperature should not be higher than 80°C. The temperature rise of the outer surface of the outer mounted bearing should not be higher than the ambient temperature of 40°C. The maximum temperature is not higher than 80°C.

4. JB/T7255-94

5.15.3  The service temperature of the bearing. The temperature rise of the bearing shall not exceed the ambient temperature by 35°C, and the maximum temperature shall not exceed 75°C.

5. JB/T7743－95

7.16.4  The temperature rise of the bearing shall not exceed the ambient temperature by 40°C, and the maximum temperature shall not exceed 80°C.

6. JB/T8644-1997

4.14 The temperature rise of the bearing shall not exceed the ambient temperature by 35°C, and the maximum temperature shall not exceed 80°C.

Motor Bearing Temperature Regulations & Abnormal Causes & Treatment

The regulations stipulate that the maximum temperature of rolling bearings does not exceed 95°C, and the maximum temperature of sliding bearings does not exceed 80°C. And the temperature rise does not exceed 55°C (the temperature rise is the bearing temperature minus the ambient temperature during the test).

1. Reason: The shaft is bent and the center line is not allowed. Process; re-center.

2. Reason: The foundation screws are loose. Treatment: Tighten the foundation screws.

3. Reason: The lubricating oil is not clean. Treatment: replace the lubricating oil.

4. Reason: The lubricating oil has been used for too long and has not been replaced. Treatment: Clean the bearings and replace the lubricating oil.

5.Reason: The ball or roller in the bearing is damaged.

Treatment: replace the new bearing. According to the national standard, F-class insulation and B-class assessment, the temperature rise of the motor is controlled at 80K (resistance method), 90K (component method). Considering the ambient temperature of 40°C, the maximum operating temperature of the motor cannot exceed 120/130°C. The maximum bearing temperature is 95°C. Use an infrared detection gun to measure the temperature of the outer surface of the bearing. According to experience, the highest point temperature of a 4-pole motor should not exceed 70°C. For the motor body, no monitoring is required. After the motor is manufactured, under normal circumstances, its temperature rise is basically fixed, and will not change or increase continuously with the operation of the motor. Bearings are vulnerable parts and need to be tested.