1. Cable joint sealing In order to prevent oil leakage from the outer circle and core wire of the lead-out cable, in addition to sealing the cable lead-out part with a sealing ring, the inner joint of the lead-out cable and the wire is sealed with epoxy glue. The joint of the lead-out cable and the power cable is also firmly connected and strictly sealed to ensure the insulation of the joint and improve the operation reliability.
2, bearings in order to ensure the reliability of oil-filled motor mechanical seal work. It is required that the motor rotor does not move axially. For this reason, two single-row radial thrust bearings of different sizes are installed in the lower part of the motor to bear the upper and lower axial forces generated when the water pump is running. The two bearings are tightly positioned with nut pins so that the shaft cannot move up and down, so as to ensure that the mechanical seal dynamic and static grinding block will not disengage during operation, resulting in oil leakage and immersion of external well water.
3. Pressure maintaining structure and lean oil protection signal device. In order to prevent well water from immersing into the motor and maintain the oil pressure in the motor greater than the external water pressure, a pressure maintaining device is installed at the lower part of the motor. The device consists of an oil bladder, an oil bladder sheath, an oil bladder gland and a spring. After the motor is filled with oil, the spring is in a compressed state, and the oil bag is filled with insulating oil. The in-machine oil pressure is maintained by the pressure generated in the oil bladder by the spring. When the pressure holding device works normally, only the insulating oil leaks out very slowly through the mechanical seal, while the well water cannot reverse into the electric cavity.
