1. The ground wire is connected to the wrong power source. There are four cores in the cable of the submersible pump. Be careful not to connect the grounding wire as the power wire.
2. The mechanical seal of the submersible pump is damaged and leaks. Frequently check the insulation resistance of the submersible pump with a megger, and take maintenance measures in time when the insulation resistance decreases, so that the motor will not burn out. 
3. Water enters after the cable is damaged. Always check the insulation resistance of the submersible pump.
4. The impeller is stuck. When the impeller is stuck and cannot rotate, the current will increase than the rated value. After a long time, the stator winding of the submersible pump will burn out soon.
5. Both ends of the stator winding touch the shell, and the winding breaks down to the ground.
6. The submersible pump "opens" and "stops" too frequently.
7. The dehydration running time of the submersible pump is too long. The dehydration operation time of the submersible pump can only be about 1 minute. After a long time, the temperature of the electric pump will rise due to poor heat dissipation.
8. Loss of phase work. When the phase is missing, the submersible pump is generally in a braking state, and the current is much larger than the rated value. At this time, the temperature of the winding of the submersible pump rises, and the stator winding will be burned out for a long time.