Influencing Factors and Treatment Methods of Motor Temperature Rise

Every summer, the hot temperature will make the motor appear "unstable", why is this? It turns out that the key factor in judging motor heating in our production is the temperature rise of the motor, not the temperature. Excessive temperature rise during the operation of the motor will accelerate the aging of the motor and reduce the power of the motor. What are the factors and solutions that affect the temperature rise of the motor? The following editor will show you.

First, electrical reasons

The quality of the power supply, whether the voltage is too high or too low, whether the three-phase voltage is balanced (in principle, it cannot exceed 5% of the rated value), and whether the phase is missing. Check for loose contacts on power cords and switches. If necessary, an AC voltmeter can be connected in parallel to the motor terminals for operational monitoring to see if the voltage is level. Good stability, whether there are ups and downs, jumping phenomenon, and then the cause of the motor failure.

Second, the reason for the motor itself.

Check if the motor cooling fan is normal, if the fan blade is damaged, if the key or top wire between the fan blade and the shaft is loose and missing. The fan cover is closed or damaged. Whether the motor has abnormal sound: It is necessary to check whether the stator and rotor of the motor are scratched, whether the bearings are damaged, and whether the lubricant is dry. Another rare fault is whether there is a crack in the rotor of the squirrel-cage asynchronous motor.

Third, use and environmental factors.

First, determine whether the motor is overloaded, whether the driven equipment is abnormal, and whether the operation violates the regulations. In the northern winter, if the ambient temperature is too low, it is easy to cause overload due to the condensation of lubricating oil! Whether the ambient temperature is too high, for equipment used in a warm environment, be sure to check the temperature of the motor. For motors in normal temperature environment, please pay attention to whether the ventilation and heat dissipation conditions of the motor are good or not. For example: debris blocking the fan's air intake, a lot of dust on the motor or internal windings....all of which can cause the motor to overheat high.

Solution:

For a running motor, if the current doesn't exceed the motor's rated current, it means the circuit is basically fine. If the original load does not change, you need to check that the voltage is at rated voltage. Typically, 380V is plus or minus 5% of normal. Check whether the ambient temperature is too high, whether the bearings are lack of oil and whether the cooling fan is damaged.

1. The load is too large. The load should be reduced or replaced with a larger capacity motor.

2. Two-phase operation. Check whether the fuse is blown, whether the switch contacts are in good contact, and troubleshoot;

3. The motor air duct is blocked. Dust or grease should be removed from the air ducts;

4. The ambient temperature rises. Cooling measures should be taken;

5. Short circuit between stator windings or phases. Check the insulation resistance between the two-phase windings with a megohmmeter or multimeter. Use the current balance method to check the three-phase winding current, the high current phase is the short-circuit phase, and the short-circuit detector can also be used to check whether the winding is short-circuited;

6. The stator winding is grounded. You can check with a multimeter or indicator light. The ground phase is the phase with zero resistance.

7. The power supply voltage is too low or too high. Check the supply voltage at the motor input using the voltage file of a multimeter or voltmeter.