Protection measures for submersible pumps.

Submersible pumps often burn out the motor windings due to a lack of water in the pool. In response to this situation, submersible pumps have added several protection measures: water shortage protection, motor water leakage protection, oil chamber water leakage protection, insulation resistance protection, winding overheating protection, bearing overheating protection, etc.

1. It is forbidden to turn on abnormal power supply voltage

Because the low-voltage power supply line is relatively long, the end voltage of the line is often too low. When the phase voltage is lower than 198V and the line voltage is lower than 342V, the motor speed of the submersible pumps will decrease. When it does not reach 70% of the rated speed, the centrifugal switch will be turned on, causing the starting winding to be energized for a long time and causing heat or burnout winding and capacitors.

On the contrary, excessive voltage causes the motor to overheat and burn out the windings. Therefore, during the operation of the submersible pump, the operator must observe the power supply voltage value at any time. If it is less than 10% of the rated voltage and more than 10% of the rated voltage, the motor should be stopped to find the cause and eliminate the fault.

2. Confirm the correct rotation direction of the motor

The direction of rotation of the motor should be clarified. Many types of submersible pumps can produce water during forward and reverse rotation. However, the water output is small and the current is large when reverse rotation. If the reverse time is long, the motor windings will be damaged.

3. Cable installation and insulation resistance requirements of submersible electric pumps

When installing the submersible pump, the cable should be overhead and the power cord should not be too long. When the submersible pump is launched into the water or lifted, do not apply force to the cable, so as not to cause the power cord to break. Do not sink into the mud when the submersible pump is working, otherwise, it will cause poor heat dissipation of the motor and burn out the motor windings. During installation, the insulation resistance of the motor should not be less than 0.5 megohm.

4. Avoid frequent switching

Do not switch the submersible pumps frequently. This is because when the electric pump stops, it will produce backflow. If it is turned on immediately, the motor load will start, which will cause the starting current to be too large and the winding will burn out. Due to the large current when starting, frequent starting will also burn out the windings of the submersible pump motor.

5. Installation of leakage protector

A leaky protector is also called a life-saving device, and its function can be understood from the three words life-saving device. Because the submersible pump works underwater, it can easily leak electricity, causing electrical energy loss and even electrocution accidents. If a leakage protector is installed, as long as the leakage value of the submersible pumps exceeds the operating current value of the leakage protector (generally no more than 30 mA), the leakage protector will cut off the power supply of the submersible pump to ensure safety, while avoiding leakage and wasting electric energy.

6. Prohibit long-term overload work of submersible pumps

To avoid long-term overloading of the submersible pumps, do not pump water with a large amount of sand and observe whether the current value is at the value specified on the nameplate at any time. If the current is found to be too large, it should be shut down for inspection. In addition, the dehydration operation time of the electric pump should not be too long, to prevent the motor from overheating and burning.

7. Pay attention to daily maintenance

Check the motor frequently. If cracks are found in the lower cover, damage or failure of the rubber seal rings, etc., they should be replaced or repaired in time to prevent water from penetrating into the machine.

8. Try to avoid starting at low pressure

The power supply voltage and the rated voltage must not differ by 10%. Excessive voltage will cause the motor to overheat and burn out the windings. If the voltage is too low, the speed of the motor will decrease. Long-term energization will heat up and even burn out windings and capacitors. Do not switch the motor frequently. This is because when the electric pump stops rotating, there will be backflow. If it is turned on immediately, the motor load will start, resulting in excessive starting current and burning of the windings.