Today, I will study the reasons for the reasons for the pump burning machine, and then focus on the maintenance of the pump with the pressure tank.

1, first of all to find out whether the motor burns the bearing (mechanical fault) or burned the coil (electrical fault)

Electrical faults include: short circuit of the stator and rotor windings, open circuit, and starting equipment failure; mechanical faults include: excessive vibration, bearing overheating, stator and rotor friction and abnormal noise, etc. If it is a fault of the burning coil, mainly Due to overcurrent, sometimes the voltage is too high or too low will cause the coil to heat short circuit, so first check if the voltage during operation is too much difference from the rated voltage.

The pump motor coil burned

There are several reasons for the overcurrent short circuit on the pump's electrical surface:

1) The equipment is overloaded, so that the motor runs at rated current or over rated current for a long time. 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 depending on the matching current of the motor and the normal running current)

2) The motor works in a damp working environment. Before the motor starts, 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.

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

4) 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.

Mechanical seal burnt map

2, the actual use of the lift is lower or higher than the pump nameplate lift too much

The lift of the centrifugal pump is used to overcome the height and resistance. When the high lift pump is working at the high lift point, its flow is the flow at the design point. If it is working at low lift, it is equivalent to the outlet resistance of the pump is reduced. 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 up or burn. If when he supplies water to a height of 60 meters. His height and resistance have increased, and its flow rate can be more than 30 cubic meters per hour. The motor runs at full capacity for a long time, and if it does not rest, it will heat up and cause the machine to burn.

Mechanical seal burned

3, the pump waterless working time is too long

In the case of a water-cooled submersible motor, the motor cannot pass through the water and cool the motor, causing the temperature of the motor to rise. If the coil does not have an overheat protection device, the motor can be burned within a few seconds to one minute. Note that the water is the main reason for the rapid burning of the motor!

4, with load start can cause motor damage

When the three-phase motor starts, the starting current is very large, which can reach 4~7 times of the rated current. A large starting current will cause a large voltage drop on the line in a short time, which not only affects the starting of the motor itself. It will affect the normal operation of other motors and electrical equipment on the same line.

5, lack of phase is another major cause of motor burnout

No matter the average motor or the submersible motor, the proportion of the phase-burning motor is 6 to 8 layers, and the second is due to the bearing damage.

6, renovate the pump with flaws

Consumers blindly compress prices, unscrupulous manufacturers are also a major reason for renovation. Unscrupulous manufacturers renovate defective pumps through recycling, after-sales, etc., making the prices cheap. In the current hardware and electromechanical market, the overall competition is fierce. In the environment, the low price means that it has a leading position in this market, and then it has evolved into a vicious circle, and the whole industry and consumers are ultimately damaged.

The water pump coil burned

Is the pump with a pressure tank longer or easier to burn the motor? ?

The working principle of the pressure tank is not elaborated. Only four parameters are mentioned:

Pump starting pressure P1

Pump stop pressure P2

Pressure tank pre-charge pressure P3

Maximum pressure of the pressure tank P4

Simply put, when P3 is less than P1, the pump starts and starts to draw water. When P4 is about P2, the pump stops working.

Therefore, if the P1 and P2 intervals of the pump are too small, the pump is very easy to work frequently, and it is easy to burn the motor when working frequently. In addition, the pre-charge pressure P3 of the pressure tank is not 0, generally about 1~4 kg. These parameters need to be adjusted according to the actual situation. Do not buy a water pump and a pressure tank. Nothing is seen, nothing is adjusted. Directly connected to the pipeline, and finally burned the motor, and did not know anything!

Finally, everyone knows that the main reason for the motor burnout is that the pump starts and stops frequently, then the problem comes:

What happens when the pump starts and stops frequently?

1. Since the user does not install the check valve when installing the self-priming pump, the water will return quickly after the pump is stopped. After the outlet pressure drops, the fully automatic variable frequency pump will start again after the preset pressure is lower. The solution to the frequent start-up of this fully automatic variable frequency pump is that the self-priming pump can solve the problem by installing a check valve at the outlet.

2. Since the faucet is not closed, or the water in other places causes the outlet pressure to drop, the self-priming pump will automatically start. Checking the faucet off state and finding out where there is water leakage is the solution for the frequent start of the automatic frequency conversion pump. Serious use of HM type tap water household self-priming pump will not appear frequent start and stop.

3. Because the distance required for transporting is long and the height is high, the pressure set on the pressure controller can not meet the requirements of use. You can open the controller cover first and then use a flat screwdriver to turn the middle adjustment knob clockwise. Rotate up to get a higher breaking pressure.

4. The reason why the automatic frequency conversion water pump is frequently started may also be due to the fact that there is no gas inside the pressure tank above the self-priming pump, check whether the pressure tank diaphragm or bladder leaks, if it leaks, pressurize or re-press pressure tank.

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