If the surface temperature at the center of the motor case is below 90°C, there is no problem with the motor. The upper limit of the temperature that an AC motor can tolerate is limited by the insulation class of the stator winding. The upper limit of the temperature is approximately 100°C for Class B (130°C) motors and 90°C for Class E (120°C) motors. If it exceeds 90°C, problems such as deterioration of the insulation performance inside the motor and shortened bearing life can occur.
Possible causes of this overheating condition include:
- Overload (load exceeding the rated torque)
- Overvoltage (a voltage exceeding the rated voltage is applied)
- Incorrect capacitor (single phase motors)
- Duty cycle
- High ambient temperature
If you use the motor outside of its specifications, as described above, it will generate a lot of heat.
If the surface temperature of the case exceeds 90°C, please recheck the operating environment.
If you are concerned about the temperature even when it is below 90°C, consider changing the motor mounting plate to one with better heat dissipation properties or using a fan for forced cooling.
