Blog

Causes and maintenance methods for motor overheating failure

Release Time:

2023-05-30 19:08

In summer, the temperature is hot, and the ambient temperature is also high, so mechanical equipment and other things heat up quickly, and the heat dissipation is not good. Over-temperature is very detrimental to the insulation resistance of the motor. The motor is sensitive to heat reaction, which is the insulation layer of the motor stator winding. Each insulation material can only bear a certain temperature. Exceeding its allowable temperature will accelerate the aging of the insulation layer and reduce the service life of the motor, and may cause various safety accidents due to insulation damage. The inspection, testing and protection of motor overheating faults are very important for reducing the failure rate, reducing accident losses and improving the economic benefits of enterprises.

Today, I will explain the reasons and solutions for the high temperature rise of the motor.

1. Today, I summarized the reasons for the excessive temperature rise of the motor: 1. The motor stator winding is blocked or there is a short circuit or grounding between phases, which increases the current and increases the adjustment loss and overheating. If the common fault is minor, you only need to re-wrap the insulation layer, and if it is very serious, you should replace the winding. 2. One-phase winding of the motor stator is short-circuited or a certain branch in the parallel winding is disconnected, resulting in unbalanced three-phase current and overheating of the winding. 3. The squirrel-cage motor rotor loses step or the winding motor rotor coil connector is loose, resulting in unstable current in the maintenance network and heat generation. The aluminum bar rotor should be repaired by welding and replaced with a new one, and the cast aluminum rotor should be replaced with the motor rotor. 4. The rolling bearing is damaged or the damage is too large, etc., so that the motor rotor collides and rubs. Check whether the rolling bearing is loose and whether the motor rotor is installed improperly. 5. If the load is too large, the load should be reduced or a motor with a large power should be used. 6. The driven working machinery has common faults that cause overload, and the driven machinery should be inspected and the fault detected. 7. Starting too frequently causes the motor to overheat, and the number of starts should be reduced. 8. If the ambient temperature is too high (higher than 40℃), the three-phase air supply will be too hot and heat dissipation will be difficult, so cooling measures should be taken. 9. Too much dust and oil stains inside and outside the motor will affect heat dissipation, and dust and oil stains should be removed. 10. The motor air duct is blocked, the ventilation is blocked, and the air intake and exhaust volume is reduced. The dirt and stains in the air duct gate should be removed. 11. The fan inside the motor is damaged, installed in reverse or not installed. It should be installed correctly, and the damaged fan should be repaired and replaced with a new one. 12. When the current exceeds 10% of the motor's rated current or is less than 5% of the motor's rated current, the motor is prone to heat up and the temperature rise increases under the rated value. The manufacturer of Dalan Motor suggests that you should check and adjust the voltage. 13. If the two-color unbalance of the three-phase power supply voltage exceeds 5%, it will cause the three-phase current to be unbalanced and cause the motor to heat up additionally. The voltage should be adjusted. 14. One-phase fuse is short-circuited or the power switch has poor contact, resulting in open-phase operation and overheating. The damaged components should be repaired and replaced with new ones. 15.  If the three-phase motor winding wiring is wrong, and the star connection is mistakenly connected to a triangle, or the triangle is mistakenly connected to a star, it will cause the motor to overheat when running under the rated value. Check and correct it.

Recommended Blog