Safety Protection Methods for Submersible Pumps

1.Prohibit starting with abnormal power supply voltage. Due to the long length of low-voltage power supply lines, low voltage at the end of the line is common. When the phase voltage is lower than 198 volts and the line voltage is lower than 342 volts, the speed of the submersible pump motor drops. When it fails to reach 70% of the rated speed, the starting centrifugal switch will close, causing the starting winding to be energized for a long time and generate heat, even burning out the winding and capacitor. On the contrary, excessively high voltage will cause the motor to overheat and burn out the winding. Therefore, during the operation of the submersible pump, the operator must observe the power supply voltage at any time. If it is lower than 10% of the rated voltage or higher than 10% of the rated voltage, the motor should be stopped to find out and eliminate the fault.

2.Confirm the correct rotation direction of the motor. The rotation direction of the motor should be clarified. Many types of high-head submersible pumps can discharge water in both forward and reverse rotation, but the water output is small and the current is large during reverse rotation. Prolonged reverse rotation will damage the motor winding.

3.Cable installation and insulation resistance requirements of submersible pumps. When installing a submersible pump, the cable should be overhead and the power cord should not be too long. Do not stress the cable when lowering or lifting the submersible pump to avoid breaking the power cord. Do not sink the submersible pump into mud during operation, otherwise it will lead to poor heat dissipation of the motor and burn out the motor winding. During installation, the insulation resistance of the motor shall not be lower than 0.5 megohms.

4.Avoid frequent switching. Do not switch the submersible pump frequently. This is because backflow will occur when the pump stops. If it is started immediately, the motor will start under load, resulting in excessive starting current and burning out the winding. Due to the large current during startup, frequent starting will also burn out the motor winding of the submersible pump.

5.Installation of leakage protector. A leakage protector is also called a life saver, and its function can be understood from the three words "life saver". Because submersible pumps work underwater, electric leakage is easy to occur, causing power loss and even electric shock accidents. If a leakage protector is installed, as long as the leakage value of the submersible pump exceeds the operating current value of the leakage protector (generally not more than 30 milliamperes), the leakage protector will cut off the power supply of the submersible pump to ensure safety and avoid electric leakage and power waste.

6.Prohibit long-term overload operation of submersible pumps. To avoid long-term overload operation of the submersible pump, do not pump water with high sand content and always observe whether the current value is within the value specified on the nameplate. If excessive current is found, stop the machine for inspection. In addition, the dewatering operation time of the pump should not be too long to avoid overheating and burning out the motor.

7.Pay attention to daily maintenance. Check the motor frequently at ordinary times. If cracks are found on the lower cover, or the rubber sealing ring is damaged or invalid, replace or repair it in time to prevent water from penetrating into the machine.

8.Try to avoid starting at low voltage. The power supply voltage shall not differ by 10% from the rated voltage. Excessively high voltage will cause the motor to overheat and burn out the winding, while excessively low voltage will reduce the motor speed. If it fails to reach 70% of the rated speed, the starting centrifugal switch will close, causing the starting winding to be energized for a long time and generate heat, even burning out the winding and capacitor. Shanghai Sunergy Pump Valve reminds: Do not switch the motor frequently. This is because backflow will occur when the pump stops. If it is started immediately, the motor will start under load, resulting in excessive starting current and burning out the winding. Check the motor frequently at ordinary times. If cracks are found on the lower cover, or the rubber sealing ring is damaged or invalid, replace or repair it in time to prevent water from penetrating into the machine.