Why is the motor burning seriously

Update:11 Jan 2020

Why is the motor burning seriously
1. High supply voltage: when the supply voltage is too high, the motor back EMF, flux and flux density will increase. Because the iron loss is directly proportional to the square of the flux density, the iron loss increases and the iron core overheats.
2. Low power supply voltage: 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 correspondingly, and the load power component in the stator current will increase accordingly, resulting in the increase of copper loss of winding, resulting in overheating of stator and rotor windings.
3. Asymmetry of power supply voltage: if one phase is not connected due to corner burn of starting equipment, three-phase motor will run in single phase, resulting in overheating of running two-phase winding through large current, and even burning.
4. Unbalanced three-phase power supply: when the three-phase power supply is unbalanced, the three-phase current of the motor will be unbalanced, causing overheating of the winding.
5. Abnormal operation of mechanical load: Although the equipment is matched, the dragged mechanical load is not working normally. During operation, the load is large and small, and the motor is overloaded and heated.
6. Motor winding open circuit: when there is one phase winding open circuit in the motor winding, or one branch in the parallel branch is open circuit, the three-phase current will be unbalanced, making the motor overheat.
7. Motor connection error: when a coil, coil group or a phase winding group is connected reversely, the motor will overheat.
Reference source: Baidu Encyclopedia - electric motor

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