In general, the main factors that affect the normal operation of submersible pumps are as follows.
(1) Leakage problem. The characteristic of submersible pumps is that they are integrated and submerged in water together, so leakage is one of the important factors affecting the normal operation of submersible pumps.
(2) Locked rotor. When the submersible pump is blocked, a blocking current of 5-7 times the normal full load current will be generated in the stator winding. Without protective measures, the submersible pump will quickly burn out. There are many reasons for the blockage of submersible pumps, such as impeller jamming, mechanical seal fragments jamming the shaft, and entanglement of dirt.
(3) The power supply voltage is too low or the frequency is too low.
(4) Wear and corrosion. Wear and tear will greatly reduce the performance of the electric pump, resulting in a decrease in flow rate, head, and efficiency. Rust on the impeller and pump cover will also cause rotor blockage. The corrosion of submersible pump parts not only affects the performance of the pump, but also shortens its service life.
(5) Cable breakage or breakage. Cable breakage and breakage not only easily cause electric shock accidents, but also the water pump is likely to be in a two-phase working state during operation, which not only does not discharge water but also easily damages the motor.
Operation and maintenance of submersible pumps
(1) Check for any cracks or breaks in the cable. Before use, both observe the appearance of the cable and use a multimeter or megohmmeter to check if the cable is connected. There should be no oil leakage at the cable outlet.
(2) Before using a new pump or starting a standby pump that has been left for a long time, a megohmmeter should be used to measure the insulation between the stator and the casing, which should not be less than 1MQ. Otherwise, the motor winding should be dried to improve the insulation level. The insulation resistance value of submersible electric pumps when they leave the factory generally exceeds 50Mr2 when measured in cold state.
(3) Check if the submersible pump is leaking oil. The possible sources of oil leakage in submersible electric pumps include cable connections, sealing at the oil filling screw in the sealing chamber, and O-ring sealing at the sealing point. When checking, it is necessary to determine whether there is really oil leakage. The reason for the oil leakage at the refueling screw is that the screw is not tightened or the oil resistant rubber pad under the screw is damaged. If it is determined that there is oil leakage at the O-ring seal, it is mostly due to the failure of the O-ring seal. At this time, it is necessary to disassemble the electric pump and replace the sealing ring.
(4) Before reusing a submersible pump that has been out of service for a long time, the upper pump casing should be disassembled, the impeller should be turned, and then the pump should be started to prevent rusting of the components and failure to produce water, which may damage the motor winding. This is more important for water filled submersible pumps