It is forbidden to start the machine with abnormal power supply voltage. Since the low-voltage power supply line is relatively long, it is common for the voltage at the end of the line to be too low. When the phase voltage is lower than 198 volts and the line voltage is lower than 342 volts, the speed of the sewage pump motor decreases. When it does not reach 70% of the rated speed, the starting centrifugal switch will be closed, causing the starting winding to be energized for a long time and heat up or even burn the winding and capacitor. On the contrary, excessive voltage causes the motor to overheat and burn the winding. Therefore, when the sewage pump is in operation, the operator must observe the power supply voltage value at any time. If it is lower than the rated voltage by less than 10% and higher than the rated voltage by more than 10%, the motor should be stopped to find out the cause and troubleshoot.
Confirm the correct direction of rotation of the motor. The direction of rotation of the motor should be clear. Now there are many types of sewage pumps that can discharge water in both forward and reverse rotation, but the water output is small and the current is large when reversing. The reversal time is long and the motor winding will be damaged.
Installation of leakage protector, leakage protector is also called life saver. Its function can be understood from the three words “life saver”. Because the sewage pump works underwater, it is easy to leak electricity, causing power loss and even electric shock accidents. If a leakage protector is installed, as long as the leakage value of the sewage pump exceeds the action current value of the leakage protector, the leakage protector will cut off the power supply of the sewage pump to ensure safety and avoid leakage and waste of electricity. The insulation resistance requirements of the cable installation and submersible electric pump. When installing the sewage pump, the cable should be overhead and the power cord should not be too long. Do not force the cable when the sewage pump is put into the water or lifted out to avoid causing the power cord to break. Do not sink into the mud when the sewage pump is working, otherwise it will cause poor heat dissipation of the motor and burn the motor winding. During installation, the insulation resistance of the motor should not be less than 0.5 megohms.
Avoid frequent switching. Do not switch the sewage pump on and off frequently. This is because backflow will occur when the electric pump stops. If it is turned on immediately, the motor load will start, resulting in excessive starting current and burning the winding. Since the current is large at startup, frequent startup will also burn the sewage pump motor winding.
Do not overload the sewage pump for a long time. To avoid overloading the sewage pump for a long time, do not pump water with a large amount of sand and observe whether the current value is within the value specified on the nameplate at any time. If the current is found to be too large, the pump should be stopped for inspection. In addition, the dehydration time of the water pump should not be too long to avoid overheating and burning of the motor. Pay attention to daily maintenance and check the motor regularly. If cracks are found on the lower cover, damage or failure of the rubber sealing ring, etc., they should be replaced or repaired in time to prevent water from seeping into the sewage pump.