Causes Of Overheating Of The Motor

1) The reason why the motor overheats in terms of power supply
In terms of power supply, the motor overheats for the following reasons:
a. The power supply voltage is too high
When the power supply voltage is too high, the motor back EMF, magnetic flux and magnetic flux density all increase. Since the magnitude of the iron loss is proportional to the square of the magnetic flux density, the iron loss increases, resulting in overheating of the core. The increase of magnetic flux leads to a sharp increase in the excitation current component, resulting in an increase in the copper loss of the stator winding and overheating of the winding. Therefore, when the power supply voltage exceeds the rated voltage of the motor, it will overheat the motor.
b. The power supply voltage is too low
When the power supply voltage is too low, if the electromagnetic torque of the motor remains unchanged, the magnetic flux will decrease, the rotor current will increase accordingly, and the load power component in the stator current will increase accordingly, resulting in an increase in the copper loss of the winding, resulting in overheating of the stator and rotor windings.
c. The power supply voltage is asymmetrical
When the power cord is open, the fuse is blown in one phase, or the gate knife
The burning of the corner head of the starting equipment causes one phase to not be connected, which will cause the three-phase motor to go single-phase, causing the running two-phase winding to overheat through high current, and burn out.
d. Three-phase power supply imbalance
When the three-phase power supply is unbalanced, the three-phase current of the motor will be unbalanced, causing the winding to overheat. It can be seen from the above that when the motor overheats, the reasons for the power supply should be considered first. After confirming that there is no problem with the power supply, consider other factors.