Maintenance of submersible pump motor
1. The submersible motor is equipped with various types of submersible pump, which is integrated with the pump and runs in the sewage of various water quality for a long time. The poor working environment determines that the sealing structure of the submersible motor is quite different from that of the conventional motor.
The submersible motor is produced according to GB / T 2818-2002 standard, which is mainly divided into oil filled type, water filled type, dry type and shield type
① The oil filled submersible motor is filled with mechanical oil, both ends of which are supported by rolling bearings, and the upper part is sealed with cemented carbide. It can be used in the occasion with large silt content, and it can also be used for tilting and horizontal.
② The water filled motor is divided into ordinary submersible motor and special submersible motor. Its main wear-resistant parts are made of imported materials (guide bearing, thrust bearing, etc.), which can bear high thrust and wear resistance.
③ Dry type submersible motor, dry type structure motor, the inner cavity is full of air, similar to the land motor, with simple structure.
④ For the shielded submersible motor, the stator of the motor is made of non-magnetic stainless steel with thin-wall shield sleeve, end ring and enclosure, and the sealed chamber is tightly closed, filled with solid filler.
The submersible pump shall use the polyethylene insulated nylon sheathed water-resistant electromagnetic wire produced by the regular manufacturer.、
2. The cause and treatment of insufficient or no water flow in the operation of 2 submersible pump
(1) The installation height of the water pump is too high, so that the immersion depth of the impeller is not enough, resulting in the decrease of the water output of the water pump; the allowable deviation of the installation elevation of the water pump shall be controlled, which shall not be expanded at will.
(2) On the contrary, before the test run of the water pump, the motor shall be idled, and the direction shall be checked to make it consistent with the water pump; in case of the above-mentioned situation during the use, check whether the phase sequence of the power supply has changed.
(3) The outlet valve cannot be opened. Check the valve and maintain it frequently.
(4) The outlet pipe is not smooth or the impeller is blocked. Clean up the blockage of the pipeline and impeller, and often salvage the sundries in the reservoir.
(5) The wear ring at the lower end of the water pump is seriously worn or blocked by sundries. Clean sundries or replace wear ring.
(6) Pumping liquid density is too high or viscosity is too high. Find out the reason of water quality change and control it.
(7) Impeller falling off or damaged. Reinforce or replace impeller.
(8) When several water pumps share the pipeline output, there is no one-way valve installed or the one-way valve is not tightly sealed. Install or replace one-way valve after checking the cause.
3. The operation of submersible pump has abnormal vibration and instability, and the main reason is
(1) The foundation bolts of the water pump base are not tightened or loosened; all the foundation bolts are tightened evenly
(2) There is no independent support for the outlet pipe, and the vibration of the pipe affects the water pump; independent and stable support is set for the outlet pipe of the water pump, so that the flange of the outlet pipe of the water pump cannot bear the load.
(3) The quality of impeller is unbalanced or even damaged or the installation is loose; repair or replace the impeller
(4) The upper and lower bearings of the water pump are damaged; replace the upper and lower bearings of the water pump.
4. Main causes of motor overload or overtemperature due to excessive current caused by submersible pump
(1) The working voltage is too low or too high; check the power supply voltage and adjust the transmission voltage.
(2) There is friction between moving and static parts in the water pump or between impeller and sealing ring; judge the position of friction parts and eliminate the fault.
(3) The motor power is inconsistent with the pump characteristics due to the low head and large flow; adjust the valve to reduce the flow to match the motor power with the pump.
(4) The pumping density is high or the viscosity is high; check the reason of water quality change and change the working conditions of the water pump
(5) The bearing is damaged; replace the bearing at both ends of the motor
The main reason and treatment of low insulation resistance of 5 submersible pump
(1) When the power line is installed, the end is immersed in water or the power line and signal line are damaged, causing water inflow; replace the cable or signal line, and dry the motor.
(2) The mechanical seal is worn or not installed in place; replace the upper and lower mechanical seals and dry the motor.
(3) The O-ring is aged and ineffective; replace all sealing rings and dry the motor.
6. In the pipeline of submersible pump, there is often obvious leakage at the connection of pipeline or flange, and the causes and treatment methods
① The pipeline itself is defective and has not passed the pressure test;
② The gasket joint at the flange connection is not treated properly;
③ Flange bolts are not tightened in a reasonable way; defective pipes shall be repaired or even replaced; if the center deviation of butt pipes is too large, they shall be removed and rearranged. After alignment, the connecting bolts shall be inserted and tightened in a basically free state. After all pipes are installed, the system's pressure strength and leakage test shall be carried out. It must be replaced with a new one.
7 internal leakage of submersible pump
When the submersible pump leaks water, it will cause insulation damage, bearing flooding, alarm system, and force the unit to stop running.
The main reasons are as follows: the dynamic seal (mechanical seal) or static seal (cable inlet special seal, 0-type seal ring) of the submersible pump is damaged to cause water seepage, and the power cable or signal cable is damaged to cause water seepage. All kinds of alsignals, such as water immersion, leakage, humidity and so on, alarm and shutdown; before installation, check the quality of each sealing part; during installation, ensure that the end faces of each sealing part are in good contact; before operation, check whether the interphase and ground insulation resistance of the motor and the sensing components of each alarm system are in good condition. In case of the above faults during operation, replace all damaged seals and cables and dry the motor. The removed seals and cables shall not be reused.
8 reverse when submersible pump stops
1. When the pump motor is cut off, the pump will reverse. The main reason is that the check valve or flap valve in the outlet pipe is out of order.
2. Before installation of the elimination measures, check shall be carried out, the installation direction of the check valve shall be correct, the center of the flap door shall be aligned, and the opening and closing shall be flexible. Check the check valve or flap valve frequently during operation, repair or replace the damaged part with a check valve or flap valve of guaranteed quality.
9. Wiring method of submersible pump
Deep well submersible pump usually only has outgoing cable when leaving the factory, and users need to connect additional cable by themselves during installation, so pay attention to the correct method when connecting the cable, otherwise it will have a great impact on the use of deep well submersible pump.
Wiring method of deep well submersible pump:
1. Strip the outer sheath and main insulation layer of the deep well pump cable, expose the copper wire of 35-40mm, repair the rubber near the core into a cone, polish the oxide layer on the core, and wipe the core and the insulation layer and sheath layer to be wrapped with alcohol (preferably hydrochloric acid) and make them dry naturally.
2, joint
1) Power cable 2) PVC tape 3) self adhesive butyl rubber tape 4) φ 1mm copper wire 5) solder 6) outgoing cable
3. Prepare 500W electric soldering iron, rosin, solder, LMM bare copper wire and insulating tape.
4. The bare copper wire shall be used to tie the cable core evenly, and the electric iron shall be used for heating and tin penetration. Repair the flat welding part with a file (no burr and sharp shuttle are allowed), and clean the part to be bound with alcohol again, and dry it.
5. The self-adhesive butyl tape is used to cover three layers in half and extend to the outside of the core gradually. When bandaging, the tape must be stretched 200%, and the outer layer will be wrapped in three layers (PVC): the official account: Pump housekeeper. The extension will also extend gradually to ensure that the binding is not less than 200mm.
6. When connecting three core cables, the positions of three joints shall be staggered for a certain distance in order to prevent short circuit.
7. Connection method when outgoing cable is double lead cable
1） After the cable is connected, the insulation resistance between the cable and the motor (when water is not added) shall be measured by shaking, and the value shall not be less than 150 megohm,
2) After the motor is filled with water, the insulation resistance of the motor winding shall be measured by shaking again, which shall not be less than 40 megohm,
3) Power on and test the steering for no more than 2 seconds. Mark the successive positions,
4) Start to run in the well: while running in the well with submersible pump, the insulation resistance shall be continuously telemetered to observe the change so as to prevent the cable insulation skin from being broken on the wall of the well. If the insulation degree is found to drop rapidly below 0.5 megohm, the unit shall be raised for detection. If there is no accident, the well can be started and commissioned through the steps mentioned above.
