the protection of submersible pumps
1. Electrical above
(1) Always review the operating voltage and direct current of the submersible pump. The three-phase voltage measured by the water pressure meter should be basically uniform, and at 340~420V, the three-phase direct current measured by the clamp-type direct current meter should be basically uniform, and it should be 0.5~1 times the extra direct current.
(2) Regularly review the thermal insulation resistance of the submersible pump to the ground. After the abnormality runs for 4~6h successively, stop and measure the insulation resistance of the motor winding to ground with a megohmmeter, which should be > 0.5MΩ. For submersible pumps that have been stopped for a short period of time, such a review should also be made before use.
(3) Before starting the machine, check the sensitivity of the thermal repeater and whether the operation of other protective installations is abnormal.
(4) Check whether the cable is damaged or not. Regarding the oil-immersed submersible electric pump, pay attention to the damaging effect of the oil leakage of the electric pump on the insulating rubber of the cable.
2. mechanically
(1) Always review the mechanical seal condition of the submersible pump. Open the oil hole screw and release a large amount of oil. If the oil contains moisture, it is indicated that the upper grinding block (or the lower grinding block) is sealed with water seepage. The sealing box should be replaced and the new freezing oil should be removed. If the oil hole is short of oil or the oil quality is not good, it should be filled with oil (No. 5 or No. 10 mechanical oil, sewing oil or transformer oil) or replaced with new oil.
(2) For the new or replaced submersible pump, the water sealing plug should be turned off after 50 hours of use, and the amount of oil (water) leaked should be checked. If it is less than 5ml, the seal is abnormal. If it can be used continuously, if it is more than 5ml, the oil (Water) After draining, tighten the sealing plug, and make a second inspection after 50 hours of continuous use. If it is still >5m1, it indicates that there is a problem with the sealing. For the used submersible pump, the amount of leakage should be checked once a month, and it should be less than 25ml, and it can be used continuously after drying.
(3) Check the vibration state of the pump motor. The synchronous speed is n0=3000r/min, 1500r/min, 1000r/min, 750r/min, and the vibration value is corresponding to δ≤0.06mm, 0.1mm, 0.13mm, 0.16 mm.
(4) Regularly review the bearing condition of the submersible pump. Check whether the bearing is short of oil, whether the inner ring or outer ring is running, and whether the bearing needs to be replaced (for the bearing of the water-filled electric pump, it is best to replace it every year).
3. rest above
(1) Always check whether the inlet mesh cover of the submersible pump is blocked by weeds and dirt, and whether the impeller is entangled.
(2) The submersible electric pump that is not necessary for a short time should be raised to the port surface, washed and dried, and then stored upright in a dry and ventilated room.
(3) After the submersible electric pump has been running for 1 to 2 years, the motor should continue to be checked and cleaned by core pulling. If there is contamination, immerse the motor in 0.2% Haiou TX-10 or 105 soap powder solution, heat it to about 100°C and stir the liquid to slow down the dissolving of contamination. After 1~2 hours of contamination, use low-pressure tap water to develop Pickled Zangjia to clean the water droplets, put it in the oven to dry at high temperature.
2. Maintenance of submersible electric pump
Common faults, causes and solutions of submersible electric pumps
Rewinding of motor rotor windings
(1) In order to prevent or reduce the insensitivity of the rotation of the rotor caused by the disassembly error, before assembling the motor, mark a symbol with the accumulator at the joint between the front and rear ends and the machine base, and disassemble it as it is after trimming.
(2) When dismantling the winding, pay attention to protect the iron core to prevent the silicon wafer from lifting, shifting, and the appearance of burrs at the slot angle. A good stitch removal procedure is to first cut the coil from one end with diagonal pliers, and then pull it out with pliers on the other end.
(3) According to the required size, the coil is wound by the winding die to ensure the outward clearance of the winding end and the coil embedded in the slot.
(4) The "three-dimensional method" is adopted for the embedded wire, that is, after one phase is embedded, the other phase is embedded, so that the end forms a "three-layer three-dimensional": pay attention when embedding: ① The first two "hanging handle" coils The position should be appropriate to ensure that the rotor core will not be scratched when the other coils are embedded; ② Use less scribe board when the bottom coil is used, so as not to damage the coil insulation; ③ The insulating paper between phases should be inserted in place, and the two-phase coils should be left wide; ④ Regarding the oil For submerged and water-filled motors, the coils in the slot (including the ends) cannot be compacted, so that the oil (water) can be fixed for the winding to dissipate heat.
(5) Solve the joint insulation. Peel off the sheath and coating at the joint, remove the paint layer and oxide layer in the name of copper wire; then continue to splicing and soldering, and remove sharp corners, burrs and residual solder; then wrap 2 layers with polyethylene tape , Use the butyl self-adhesive tape stretched about 2 times to half-stack 6 layers (the joints should be meticulous and seamless), and initially use polyethylene adhesive tape or polyester tape to half-stack 2 layers as a mechanical cover.
(6) Keep dirty when disassembled. Carefully adjust the "limit screw" at the bottom to make the screw rotate freely, and tighten the locking nut. Install the end cap in its original position, taking care not to damage the rubber seal ring of the inner hole of the sealing box. When disassembling the whole-body sealing box, it can only be pushed in slightly, so as not to knock.
3. Attempt to disassemble the motor
(1) Air pressure attempt. Use the air pressure of 2kg/mm2 to check whether the "O"-shaped rubber sealing ring at the joint of the whole machine and the two secret book covers in the whole-body sealing box are breathable. After airtight, add mechanical oil to the upper and lower covers.
(2) DC resistance. The resistance value of each phase winding of the rotor should be within the ±2% error range of the average value of the three-phase winding resistance.
(3) Insulation resistance. Should be > 5MΩ at room temperature.
(4) Mechanical review. When the electric pump is running, the pitch of each element should be deformed.
(5) Shipboard attempt. The shipboard DC current and the shipboard loss under the extra voltage are not much different from the original motor. The 2.2kW submersible pump, which is rarely used, has a DC power of 1.8~2.5A, and the loss of the ship is less than 0.5kW.
(6) Load attempt. After running in water for 4 hours, the temperature rise of the motor is ≤75℃.
(7) Braking attempt. Tie the impeller and connect the 100V phase exchange power supply. The DC value of each phase should be within the ±10% error range of the average value of the three-phase DC.
