How to maintain a sewage submersible pump

Pumps are used very frequently in wastewater treatment. So how can we make our pumps last longer and perform better? 1. Determine the correct motor rotation direction. It’s crucial to understand the motor’s rotation direction. Many types of submersible sewage pumps can pump water in both forward and reverse rotation, but the flow rate is lower and the current is higher during reverse rotation. Prolonged reverse rotation can damage the motor windings.2. Prevent abnormal power supply voltage during startup. Because low-voltage power lines are relatively long, it’s common for the voltage at the end of the line to be too low. When the phase voltage is below 198 volts and the line voltage is below 342 volts, the submersible sewage pump motor speed decreases. When it doesn’t reach 70% of the rated speed, the starter switch will close, causing the starter windings to be energized for an extended period, leading to overheating and potentially burning out the windings and capacitors. Conversely, excessively high voltage causes the motor to overheat and burn out the windings. Therefore, during operation, the operator must constantly monitor the power supply voltage. If it’s below 10% of the rated voltage or above 10% of the rated voltage, the motor should be stopped, the cause identified, and the fault rectified. 3. Insulation Resistance Requirements for Cable Installation and Submersible Sewage Pump When installing a submersible sewage pump, the cable should be overhead, and the power cord should not be too long. Do not stress the cable when lowering or raising the submersible sewage pump to prevent the power cord from cracking. Do not submerge the submersible pump in mud during operation, otherwise it will cause poor motor heat dissipation and burn out the motor windings. During installation, the insulation resistance of the motor should not be lower than 0.5 megohms.4. Installation of Residual Current Device (RCD) An RCD, also called a life-saving device, serves the purpose of protecting the submersible sewage pump. Because submersible sewage pumps operate underwater, leakage can easily cause power loss and even electric shock. If an RCD is installed, it will cut off the power supply to the submersible pump if the leakage current exceeds the RCD’s operating current value (usually not exceeding 30 mA), ensuring safety and preventing leakage and energy waste.5. Prevent Frequent On/Off Switching Avoid frequently switching the submersible pump on and off. This is because backflow occurs when the pump stops. If it is immediately restarted, the motor will be overloaded, resulting in excessive starting current and burning out the windings. Because the starting current is very high, frequent starting will also burn out the submersible sewage pump motor windings.6. Avoid Prolonged Overload Operation of the Submersible Sewage Pump To prevent prolonged overload operation of the submersible pump, do not pump water with high sand content and regularly check the current value to ensure it matches the value specified on the nameplate. If excessive current is detected, stop the pump and inspect it. Additionally, the pump should not be run dry for extended periods to prevent the motor from overheating and burning out.7. Pay Attention to Routine Maintenance Regularly inspect the motor. If cracks are found in the lower cover, or the rubber sealing ring is damaged or ineffective, replace or repair it promptly to prevent water from entering the submersible pump.Paying attention to the use of the submersible sewage pump protector and performing routine maintenance can significantly extend the service life of the submersible sewage pump.