What Conditions Will Cause The Centrifugal Pump To Burn Down The Motor?

Jan 23, 2021

The main reasons for the burning of centrifugal pump motors are as follows:

First of all, first find out whether the motor burned the bearing (mechanical failure) or burned the coil (electrical failure).

If it is the fault of burning the coil, it is mainly caused by overcurrent. Sometimes the voltage is too high or too low to cause the coil to heat up and short circuit, so first check whether the voltage during operation is too much different from the rated voltage.

There may be several reasons for over-current short-circuit:

1. Overload operation of centrifugal pump makes the motor run at rated current or over-rated current for a long time. Special attention should be paid to the fact that the starting current of the motor is 3-5 times the rated current, so it is necessary to avoid running the centrifugal pump with load or full load when starting the centrifugal pump (mainly depends on the matching margin of the rated current of the motor and the normal operating current) .

2. The mechanical failure of the centrifugal pump causes the motor to be overloaded, the current is too large and the coil is burnt.

3. The heat dissipation of the motor has a problem. Generally, motor coils are air-cooled, and submersible pumps are water-cooled. If the cooling water (air) is cut off, the coil cannot dissipate heat, and the coil may be burnt.

4. The motor works in a humid working environment. Before starting the motor, the ground insulation and phase-to-phase insulation of the coil should be checked. The insulation requirements for different voltage levels are also different. You can refer to the relevant national standards for checking. During the operation of the motor, attention should be paid to the waterproof and moisture-proof of the motor.

The head of a centrifugal pump is used to overcome height and resistance. When a high-lift pump is working at a high-head point, its flow is the flow of the design point. If it is working at a low-head, it is equivalent to the reduction of the outlet resistance of the centrifugal pump. At this time, the flow of the centrifugal pump will increase, the motor will be overloaded, and the motor will be burned if it exceeds a certain level. For example, a feedwater pump has a head of 50 meters and a flow rate of 50 cubic meters per hour. When it feeds 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 may reach 80-90 cubic meters per hour or more, then the motor will heat up or burn.