It is necessary to find out the rotation direction of the motor. Now there are many types of submersible pumps that can discharge water when rotating forward and reverse, but when reversing, the output water is small and the current is large, and the long reversal time will damage the motor winding.
Because the low-voltage power supply line is relatively long, the terminal voltage of the line is often too low. When the phase voltage is lower than 198 V and the line voltage is lower than 342 V, the speed of the submersible pump motor will drop. When the rated speed is not reached 70%, the startup centrifugal switch will close, causing the startup winding to be electrified for a long time and heating or even burning the winding and capacitor. On the contrary, the high voltage causes the motor to overheat and burn out the winding. Therefore, during the operation of the submersible pump, the operator must observe the voltage value of the power supply at any time. If it is lower than 10% of the rated voltage and higher than 10% of the rated voltage, the motor shall be stopped to find out the cause and eliminate the fault.
When installing the submersible pump, the cable should be overhead and the power line should not be too long. When the submersible pump is under water or raised, do not force the cable, so as to avoid breaking the power line. Do not sink into the mud when the submersible pump is working, otherwise the motor winding will be burnt due to poor heat dissipation. During installation, the insulation resistance of the motor shall not be less than 0.5 megohm.
Leakage protector is also called life protector. Its function can be understood from the three words "life protector". Because the submersible pump works underwater, it is easy to cause electric energy loss or even electric shock accident due to leakage. If a leakage protector is installed, as long as the leakage value of the submersible pump exceeds the action current value of the leakage protector (generally no more than 30mA), the leakage protector will cut off the power supply of the submersible pump, ensure safety, and avoid leakage and waste of electric energy.
Do not switch on and off the submersible pump frequently, because there will be backflow when the electric pump stops running. If it is started immediately, the motor will be started with load, resulting in excessive starting current and burning of the winding. Due to the large current during start-up, frequent start-up will also burn out the motor winding of submersible pump.
In order to avoid long-term overload operation of the submersible pump, do not pump water with large sediment content and observe whether the current value is specified on the nameplate at any time. If it is found that the current is too large, it shall be stopped for inspection. In addition, the dewatering operation time of the electric pump should not be too long to avoid overheating and burning of the motor.
Because when disassembling by oneself, first, I don't know where the fault is, resulting in blind random disassembly; second, I don't have special tools, which often damage the original intact parts. The best way is to go to an experienced and large-scale maintenance point for maintenance, and timely replace "over age" parts and some vulnerable parts. Under normal circumstances, the water pump shall be maintained once every half a year to prevent "sick" operation.
Whether the rotation of the pump shaft is normal and whether it is stuck; whether the position of the impeller is normal; whether the cable and cable plug are cracked, scratched and broken, etc. Pay attention to the change of voltage during operation, and generally control it within ± 5% of rated voltage. In addition, the position of the water pump in the water is very important. It should be selected in the place with abundant water, no silt and good water quality as far as possible. It should be suspended vertically in the water and not allowed to be placed horizontally, so as to avoid falling into the mud or being blocked by the suspended substance at the inlet of the water pump, resulting in the sharp reduction of the water output or even the inability to pump water.
Otherwise, it is easy to burn the motor if it runs for a long time. For example, when a farmer uses a self-priming pump, the motor is overheated and the coil is burnt because the plastic film covering the motor is not removed. In addition, before starting, it is necessary to check the water storage in the pump body, otherwise, it will not only affect the self-priming performance, but also easily burn the shaft seal components. Under normal conditions, the water pump should be discharged 3-5 minutes after starting, otherwise, it should be stopped immediately for inspection.
Then place it in a dry place. If possible, users can also apply grease to the key parts of the water pump and add lubricating oil to the bearing to prevent parts from rusting. In addition, the non service life of the pump is not the longer the better. If it is not used for a long time, it will not only easily rust parts, but also reduce the service life of the pump.
Pay attention to the daily maintenance of submersible sewage pump: always check the motor at ordinary times. If cracks are found on the lower cover, rubber seal ring is damaged or invalid, it should be replaced or repaired in time to avoid water infiltration into the submersible pump. Pay attention to the use of the submersible pump protector and pay attention to some daily protection, which can better extend the service life of the submersible pump.
