1, The use of submersible pumps
1. Pre use inspection
(1) Check if there are cracks in the casing of the submersible pump. If there are cracks, it cannot be used.
(2) Check if the seals at the discharge holes, drain holes, oil discharge holes, and cable joints of the submersible pump are loose. If they are loose, they must be tightened.
(3) Check the insulation resistance of the submersible pump. Use a 500V insulation resistance meter to test, and the insulation resistance should not be less than 5M Ω. If it is lower than this value, open the drain and vent holes, dry or sun dry before use.
(4) It is best not to have joints in the cable of the submersible pump. If there are joints, they should be wrapped properly, and the entire cable should be free of damage or breakage. Otherwise, a new cable should be replaced. Additionally, the cable should be overhead and not too long.
(5) Before starting, calibrate the positive and negative poles of the power supply to prevent the water pump from reversing and not producing water.
(6) Before starting up, conduct a comprehensive inspection of the power supply lines and switches, and run them on the ground for 3-5 minutes. If they operate normally, put them into water and put them into use.
2. Precautions to be taken during use
(1) Different models of submersible pumps should be used according to the specified head, and the inner diameter of the steel pipe, rubber pipe or sail pipe used should meet the technical requirements.
(2) Try not to bend the water outlet pipe as much as possible, and promptly detect and repair the rupture of the water supply pipe to reduce power loss.
(3) When placing or lifting a submersible pump into or out of the water, it is necessary to hold the rope on the earring and never pull the cable, otherwise it may cause damage to the cable.
(4) Submersible pumps should not pump out sewage or water with high sand content, especially when using mechanical seals.
(5) The power supply for submersible pumps should be selected according to regulations, and the distance between the power supply and the pump should not be too far. The voltage should be within ± 10% of the normal value, and an iron rod of more than 1m should be buried at the power supply or pump as a ground wire to ensure safety. The power supply must be reliably grounded and equipped with a leakage protector. In addition, try to avoid starting the motor when the power supply voltage is too high or too low. High voltage can cause the motor to overheat and burn out the windings; If the voltage is too low, the motor speed will decrease, which will cause the starting winding to overheat for a long time, and even burn out the winding and capacitor.
(6) The diving depth of a submersible pump is generally 0.5-3m, and it should be lifted vertically, not lying horizontally, and not sinking into sediment.
(7) Submersible pumps should use circuit breakers as control equipment, and can also use three knife switches, but must be equipped with 6A electric fuses.
(8) Submersible pumps should not be started or stopped too frequently. After stopping, they should be restarted every 3-5 minutes. Due to the large current passing through the motor during startup, if the motor is started frequently, heat will accumulate inside the motor, the temperature will rise, affecting the insulation performance of the winding and causing it to burn out.
(9) Submersible pumps are not suitable for dehydration operation. When pumping water from the pool, attention should be paid to the decrease in water level to prevent the power source from being exposed to the water surface. The on-site interview time is 3-5 minutes, otherwise it may burn out the motor.
(10) Submersible pumps should be supervised by a dedicated person during operation. If any abnormalities are found, the power should be immediately turned off and inspected.
(11) During the use of submersible pumps, do not wash, swim or let livestock into the water nearby to prevent electric shock accidents. If a leakage phenomenon is found, the power should be quickly cut off and checked for handling.
(12) When the impeller reverses after the water pump is running, the machine should be stopped immediately and any two of the three-phase core wires should be replaced to ensure normal operation.
3. Common faults
1. Abnormal vibration
Main reason: The foundation bolts of the water pump base are not tightened or loose; The water outlet pipe does not have independent support, and the stability of the pipeline affects the water pump; The quality of the impeller is unbalanced, with damage or loose installation; The upper and lower bearings of the water pump are damaged
Troubleshooting: Tighten all foundation bolts evenly; Install independent pipeline supports for the water supply pump to prevent the flange of the pump outlet pipe from bearing loads; Repair or replace the impeller; Replace the upper and lower bearings of the water pump
2. Insufficient traffic
Main reason: The installation height of the water pump is relatively high, which prevents the impeller from fully immersing, resulting in a decrease in the water output of the water pump; The water pump rotates in the opposite direction; The outlet valve cannot be opened; The outlet pipe is not smooth or the impeller is blocked; The wear-resistant ring at the lower end of the water pump is severely worn or blocked by debris; The density or viscosity of the pumped liquid is too high; Impeller detachment or damage; Multiple water pumps share the same pipeline for output, and the sealing of the one-way valve is not tight or there is no one-way valve installed
Troubleshooting: Control the allowable deviation of the installation elevation of the water pump and do not arbitrarily expand it; Before running the water pump, the motor should be idle and the direction of the water pump should be checked. If the direction is not correct, check whether the power phase sequence is incorrect; Check valves and perform regular maintenance; Clean up blockages in pipelines and impellers, and regularly salvage debris from the reservoir; Replace the wear-resistant ring and clean the debris; Re match with a suitable pump; Reinstall or replace directly; Install the one-way valve and replace the one-way valve seal
3. Unable to start
Main reasons: poor contact between power switch and plug; The fuse of the control circuit is blown; The fuse of the main circuit is blown; Two phase submersible pump capacitor burned out; Three phase submersible pump not synchronized
4. Electric leakage
Leakage is the most common fault of submersible pumps and one of the most dangerous factors that endanger personal safety. The fault phenomenon is that when the circuit breaker is closed, the leakage protector in the transformer distribution room trips (without a leakage protector, it would be quite dangerous and could cause the motor to burn out). This is mainly due to water entering the submersible pump body, causing a decrease in the insulation resistance of the submersible pump motor winding, resulting in the action of the protector. At this point, use the R × 10k Ω range of a shaking or multimeter to measure the leakage resistance of the motor winding to the casing. Long term use of the water pump causes severe wear on the mechanical seal end face, allowing water to seep in and wet the motor winding, resulting in leakage. The removed submersible pump motor can be placed in a drying room or dried using 100-200W incandescent bulbs; Measure the insulation resistance to infinity, then replace the mechanical seal and install the pump before putting it into use.
5. Oil leakage
The oil leakage of submersible pumps is mainly caused by severe wear of the sealing box, resulting in oil leakage in the oil chamber of the sealing box or poor sealing at the outlet box.
When the oil chamber of the sealed box leaks oil, oil stains can be seen at the inlet joint. There is an oil filling hole at the inlet joint. Unscrew the screw and observe whether the oil chamber is filled with water. If water enters the oil chamber, it indicates poor sealing and the sealing box should be replaced to prevent severe water ingress into the motor. If there is oil leakage at the root of the submersible pump cable, it belongs to oil leakage inside the motor. Generally, it is caused by poor sealing of the sealant plug or unqualified lead wires after motor rewinding; Some are caused by the rupture of the water pump wiring board. After the inspection is confirmed, replace it with a qualified new product. And measure the insulation level of the motor. If the insulation is poor, it should be dealt with in a timely manner, and the oil inside the motor should be replaced.
6. After being powered on, the impeller does not rotate
After being powered on, the water pump makes a buzzing AC sound and the impeller does not rotate. Cut off the power and move the impeller at the inlet. If it cannot be moved, it indicates that the rotor is stuck. Can the water pump be disassembled for inspection to see if the bearing ball at the lower end of the rotor is broken, causing the rotor to get stuck; If the impeller can be turned, but does not rotate after being powered on, the cause of the fault may be severe bearing wear. The magnetic force generated by the stator during power on will attract the rotor and prevent it from rotating. Replace the bearings and reassemble the water pump. Adjust the impeller flexibly and troubleshoot.
4. The water pump has weak output and low flow rate
Take out the water pump and check that the rotor rotates flexibly and can rotate when powered on. Upon disassembling the water pump for inspection, it was found that there was looseness between the lower shaft and bearing of the water pump, and the rotor had moved downwards, resulting in weak rotation of the rotor and low output power. Use appropriate washers to pad between the rotor and bearings, move the rotor upward, install and test the machine, and the fault can be eliminated.
Troubleshooting: repair or replace; Replace the fuse; Replace with a brand new capacitor; Connect the disconnected phase circuit.
2, Maintenance and upkeep of submersible pumps
Submersible pumps are used by submerging the water pump and motor into the water. If the technical performance does not meet the requirements, not only can it not pump water, but it may also cause safety accidents. Therefore, it is necessary to pay attention to the maintenance and upkeep of submersible pumps.
1. Regularly check the seals
If water enters the interior of a submersible pump, it can cause the motor to short-circuit and burn out. Therefore, before each use, it is necessary to check the various sealing components of the submersible pump. If any looseness is found, it should be tightened in a timely manner. If the sealing components are damaged, they should be replaced with new ones in a timely manner. After every 50 hours of operation, the submersible pump should be lifted off the ground and the sealing components should be inspected to ensure safe use.
2. Regularly replace lubricating oil
After 500 hours of operation, the oil in the sealed chamber of the oil immersed submersible pump should be replaced. After one year of work, the oil in the motor compartment should be replaced. And attention should be paid to the brand of the engine oil. The engine oil used for submersible pumps is generally No. 5 or No. 10 engine oil. Different grades of engine oil cannot be mixed for use.
After continuous operation for 2000 hours, the wet submersible pump needs to replace the lubricating oil once. The replaced lubricating oil is lithium based grease, and calcium based grease cannot be used.
3. Regular rust removal
After one year of use, the submersible pump should be inspected for corrosion, rust should be removed, and a layer of anti rust paint should be applied for protection.
4. Regular maintenance
After every two years of use, submersible pumps should undergo a comprehensive inspection. All components should be disassembled, inspected, cleaned, lubricated, and then reassembled.
5. Storage and maintenance
When the submersible pump is not used for a long time, it should not be immersed in water. It should be lifted to the ground, wiped dry of water stains, and hung in a dry and ventilated room.
3, Common faults and troubleshooting methods of submersible pumps
1. The pump cannot start
Reason: The power supply voltage is too low; There is a circuit break somewhere in the circuit; The pump impeller is stuck by foreign objects; Cable breakage; The voltage drop of the cable is too high, and the cable plug is damaged; One phase of the three-phase cable is not connected; The winding in the motor room is burnt out.
Exclusion method: Adjust the voltage to 342V~418V; Identify the cause of the power outage and eliminate it; Dismantle the guide piece and remove debris; Replace according to the cable specification table; Use thicker cables instead; Replace the new plug, check the switch outlet and cable; Overhaul the electric motor.
2. The pump does not produce water after starting, produces little or intermittent water
Reason: The electric motor cannot start; Pipeline blockage; Pipeline rupture; The water filter is blocked; The suction port is exposed above the water surface; Reverse rotation of the motor, damage to the pump casing sealing ring and impeller; The head exceeds the rated head of the submersible pump by too much; The impeller rotates in reverse.
Troubleshooting method: eliminate circuit faults; Remove blockages; Repair welding or replacement of pipes; Remove blockages; Reinstall; Swap the wiring position of the power cord; Replace with new parts; Replace the high head pump; Reinstall.
3. The electric motor cannot start and is accompanied by sound
Reason: One of the phases is open circuit; Bearing holding shaft; There are foreign objects inside the impeller and the pump body is stuck.
Exclusion method: repair the circuit; Repair or replace bearings; Remove foreign objects.
4. Sudden interruption of pump water output and motor shutdown
Reason: Air switch tripped or fuse blown, power outage; The stator winding is burnt out; Impeller stuck; Water shortage in the wet submersible pump motor; The motor of the oil filled wet submersible pump is short of oil.
Troubleshooting method: Check for circuit faults, motor winding faults, and eliminate them; Check the cause of power outage and eliminate the fault; Repair the stator winding; Eliminate clutter; Repair the motor.
5. The current is too high and the ammeter pointer swings
Reason: rotor sweeping; The relative rotation between the shaft and the bearing is not flexible; Due to severe wear of the thrust bearing, the impeller is worn against the sealing ring; The shaft is bent and the bearings are not concentric; The dynamic water level drops below the inlet; Insufficient submergence depth of impeller, causing vibration due to air intake; The impeller compression nut is loose.
Exclusion method: Replace the bearing; Replace or repair bearings; Replace the thrust bearing or thrust disc; Send to the factory for repair; Adjust the throttle, reduce the flow rate or change the well; The electric pump moves downwards; Tighten the nut.
6. Severe vibration during unit operation
Reason: The rotor of the electric motor is unbalanced; The impeller of the water pump is unbalanced; Bending of motor or pump shaft
