First, make it clear that the motor is a mechanical fault. If the fault is a burning coil, it is mainly caused by overcurrent. Sometimes the voltage is too high or too low, which will cause the coil to be short-circuited. Therefore, check the voltage during operation. There is too much difference from the rated voltage. Over current short circuit, there may be several reasons:

A. The equipment is overloaded to operate the motor for a long time at rated current or over rated current. It is important to note that the starting current of the motor is 3-5 times of the rated current, so it should be avoided to start the equipment with load or full load (mainly depends on the matching current of the motor and the normal running current)

B. The motor works in a damp working environment. Before the motor is started, the ground insulation and phase insulation of the coil should be checked. The insulation requirements for different voltage levels are different. You can check it according to the relevant national standards. During the operation of the motor, attention should be paid to the waterproof and moistureproof of the motor.

C. The mechanical failure of the pump causes the motor to be overloaded, and the current is too large to burn the coil.

D. the heat dissipation of the motor is a problem. Generally, the motor coils are air-cooled and the submersible pump is a water-cooled casing. Large motors are mostly cooled by air-to-air heat exchangers and air-to-water heat exchangers. If the cooling water (air) is broken and the coil cannot be dissipated, the coil may be burnt.

Second, the actual use of the lift is lower than the pump nameplate lift. The lift of the centrifugal pump is used to overcome the height and the resistance. When the high lift pump is working at the high lift point, his flow is the design point flow, if it is working at low lift. It is equivalent to the reduction of the outlet resistance of the pump. At this time, the flow rate of the centrifugal pump will increase, and the motor will be overloaded. If it exceeds a certain level, the motor will be burnt. For example, a feed pump has a head of 50 meters and a flow rate of 50 cubic meters per hour. When it supplies water to a height of 50 meters, its flow rate is 50 cubic meters per hour. When it feeds water to a height of 40 meters, Its height and resistance reduce its flow rate to 80-90 cubic meters / hour or more, when the motor will heat or burn.

Third, the water pump does not work too long. Fourth, with the load start can cause motor damage