What are the common faults of water pumps

1. Unable to start

First, check the power supply situation: whether the connection of the connector is firm; Whether the switch contact is tight; Has the fuse blown? Whether there is a phase loss in three-phase power supply, etc. If there is an open circuit, poor contact, blown fuse or phase loss, the cause should be identified and repaired in time. Secondly, check whether it is a mechanical fault of the water pump itself. Common causes include: the packing is too tight or the impeller and the pump body are blocked by debris. The pump shaft, bearings and leakage reduction rings are rusted. The pump shaft is severely bent, etc. Troubleshooting method: Loosen the packing and unclog the water diversion channel. Disassemble the pump body to remove debris and rust. Remove the pump shaft for calibration or replace it with a new one.

2. The water pump is overheating

Cause: Bearing damage; The clearance of the rolling bearing or bracket cover is too small; The pump shaft is bent or the two shafts are not concentric. The tape is too tight. Lack of oil or poor oil quality; The balance hole on the impeller is clogged, causing the impeller to lose balance and increasing the thrust to one side. Troubleshooting method: Replace the bearing; Remove the rear cover and install a gasket between the bracket and the bearing housing. Investigate the pump shaft or adjust the concentricity of the two shafts; Adjust the tightness of the tape appropriately; Add clean grease, with the grease accounting for about 60% of the clearance inside the bearing. Clear the blockage in the balance hole.

3. Insufficient traffic

This is because: the power speed is not matched or the belt slips, causing the speed to be too low. The installation Angle of the axial flow pump blade is too small. Insufficient head, overly long pipeline or right-angle bends in the pipeline; The suction lift is too high; Local blockage or damage to the bottom valve, pipeline and impeller; The outlet pipe is leaking seriously. Troubleshooting method: Restore the rated speed, remove the oil stains on the belt, and adjust the belt tightness properly. Adjust the blade Angle properly, lower the installation position of the water pump, shorten the pipeline or change the curvature of the pipeline. Seal the air leakage point of the water pump and press the packing tightly. Clear the blockage and replace the impeller. Replace the leakage reduction ring and block the leakage point.

4. Unable to absorb water

The reasons are that there is air in the pump body or air accumulates in the inlet pipe, or the bottom valve is not closed tightly, resulting in insufficient priming water, severe air leakage of the vacuum pump packing, or the gate valve or flap gate is not closed tightly. Troubleshooting method: First, increase the water pressure, then fill the pump body with water, and finally start the machine. At the same time, check whether the check valve is tight and whether there is any air leakage in the pipeline and joints. If air leakage is found, disassemble it, apply lubricating oil or mixing paint to the joints, and tighten the screws. Check the oil seal ring of the water pump shaft. If it is severely worn, replace it with a new one. The pipeline is leaking water or gas. It's possible that the nut wasn't tightened enough during installation. If the leakage is not severe, apply cement or cement slurry mixed with asphalt oil to the leaking area. For temporary repairs, apply some wet mud or soft soap. If there is water leakage at the joint, the nut can be tightened with a wrench. If the leakage is severe, the pipe must be reassembled and the cracked one replaced. Reduce the head and press the pipe opening of the water pump 0.5 meters underwater.

5. Severe vibration

The main reasons are as follows: The electric rotor is unbalanced; The coupling is poorly combined. Bearing wear and bending; The parts of the rotating section are loose or cracked. Reasons such as unstable pipe supports. It can be dealt with by methods such as adjustment, repair, reinforcement, straightening and replacement respectively. The above situation is a common cause of water pump failure, but not the only one. In practice, when dealing with faults, based on actual analysis, the principle of "outside first, then inside" should be followed. Do not operate blindly.

6. The matching power motor overheats

There are four reasons. One reason is related to the power supply: If the voltage is too high or too low, under a specific load, if the voltage variation range is outside +10% to -5% of the rated value, it will cause the motor to overheat. The three-phase voltage of the power supply is asymmetrical. If the phase-to-phase imbalance of the three-phase voltage of the power supply exceeds 5%, it will cause the winding to overheat. Experience shows that over 85% of agricultural motors are burned out due to phase loss operation. Phase loss protection devices should be installed on the motors. The second reason is related to the water pump: the selected power is not matched, a small horse pulling a big cart, and the motor has been overloaded for a long time, causing the motor temperature to be too high. Motors that start too frequently or are rated for short-time or intermittent operation operate continuously. The number of starts should be limited, thermal protection should be correctly selected, and the calibration on the motor should be followed

The quota usage. The third reason is due to the motor itself: incorrect connection method, mistakenly connecting a △ shape to a Y shape, causing the motor's temperature to rise rapidly; There are interphase short circuits, inter-turn short circuits or local grounding in the stator winding. In mild cases, the motor will overheat locally; in severe cases, the insulation will be burned out. If the squirrel-cage rotor has broken bars or defects, the core temperature of the motor will rise rapidly after running for 1 to 2 hours. When the ventilation system malfunctions, it is necessary to check whether the fan is damaged, whether its rotation direction is correct, and whether the ventilation holes and channels are blocked. Bearing wear and rotor eccentricity scraping cause the stator and rotor cores to rub against each other, producing metallic clashing sounds. The core temperature rises rapidly. In severe cases, the motor smokes and even the coils burn out. The fourth reason is related to the working environment: The motor windings get damp or dust, oil stains, etc. adhere to the windings, resulting in a decrease in insulation. The insulation resistance of the motor should be measured and it should be cleaned and dried. The ambient temperature is too high. When the ambient temperature exceeds 35℃, the high intake air temperature will cause the motor temperature to be too high. Measures should be taken to improve its working environment. Such as building sheds for shade, etc. Note: In case of malfunction due to electrical reasons, it should be repaired by an electrician with a professional qualification certificate. People with only a superficial understanding should not repair it blindly to prevent personal injury accidents.

7. The deep well submersible pump does not supply water or the water volume is small

First, take a look at how much the current of the water pump at operation differs from that during normal operation. If it is smaller than the normal operating current (basically two-thirds of the normal current), then there will be problems such as impeller wear and blockage of the check valve on the pump head. If the current is as large as usual, then there are problems such as leakage of the pipe gasket, the pipe, or the pump body. If the current is larger than during normal operation, it can basically be determined that it is a problem of wear and tear of vulnerable parts. In addition, if the cable is damaged, the water volume will remain the same as usual, but the current will increase. The current of three 380V motors is generally 2.2A. The above reasons can be identified by any repairman who frequently maintains deep well pumps.