1. Use previous preparation work
(1) Check whether the cable is cracked or broken. Before use, it is necessary to observe the appearance of the cable and use a multimeter or megohmmeter to check if the cable is properly connected. There shall be no oil leakage at the cable outlet.
(2) Before using a new submersible sewage pump or starting a long-term standby pump, a megohmmeter should be used to measure that the insulation between the stator and the casing is not less than 1MQ. Otherwise, the motor winding should be dried to improve the insulation level.
The insulation resistance value of submersible electric pumps at the time of leaving the factory generally exceeds 50Mr2 when measured in cold state.
(3) Check if the submersible sewage pump leaks oil. The possible oil leakage routes of submersible electric pumps include cable connections, sealing at the oil filling screw in the sealing chamber, and O-ring seals at the sealing points. During inspection, it is necessary to determine whether there is a genuine oil leak. The reason for oil leakage at the refueling screw is that the screw is not tightened or the oil resistant rubber gasket under the screw is damaged. If it is determined that there is oil leakage at the sealing point of the O-ring, it is mostly due to the failure of the O-ring seal. At this time, the electric pump needs to be disassembled and the sealing ring needs to be replaced.
(4) Before reusing a submersible electric pump that has been out of service for a long time, the previous pump casing should be disassembled, the impeller should be turned, and then restarted to prevent rusting of the components and failure to produce water, which could damage the motor winding. This is more important for water filled submersible electric pumps.
2. Precautions for the operation of submersible sewage pumps
(1) When the submersible sewage pump is tested without water, the operating time must not exceed the rated time. The capacity of the suction tank can ensure that the water level is high when the submersible sewage pump is turned on and in operation, to ensure the cooling effect of the motor and avoid frequent starting and stopping caused by large fluctuations in water level. The frequent starting of large and medium-sized submersible sewage pumps has a significant impact on their performance.
(2) When the humidity sensor or temperature sensor issues an alarm, or when there is abnormal vibration or noise during the operation of the pump body; When the output water volume and pressure decrease, or when the power consumption significantly increases, the submersible sewage pump should be immediately shut down for maintenance.
(3) When some poorly sealed submersible pumps are immersed in water for a long time, even if they are not used, their insulation value will gradually decrease and they will eventually be unable to be put into use, and even insulation disappearance may occur in a shorter period of time than the continuous operation of submersible sewage pumps in water. Therefore, the backup function of a submersible pump in the suction tank may not always be effective. If conditions permit, it can be used as a dry backup outside the tank. When a submersible pump in operation fails, it should be immediately stopped and lifted up, and the backup pump should be put down again.
(4) Submersible pumps should not be started or stopped too frequently, otherwise it will affect the service life of the submersible pump. When the submersible pump stops, the water in the pipeline flows back. If it is restarted immediately, it will cause the load on the electric pump to be too heavy and bear unnecessary impact loads; In addition, frequent opening and stopping of submersible pumps can damage components with poor impact resistance and cause damage to the entire electric pump.
(5) After shutdown, the motor cannot be restarted until it has completely stopped running.
(6) When checking the electric pump, the power must be cut off.
(7) When the submersible pump is working, do not wash items, swim or let livestock into the water nearby to avoid electric shock accidents in case of leakage of the electric pump.
