1. Unable to start or difficult to start
Fault performance:
The motor is unresponsive or only makes a humming sound after the power is turned on, and cannot run normally.
The starting current increases abnormally, causing the fuse to blow or the circuit breaker to trip.
Possible causes:
Electrical failure: power supply voltage is too low, phase shortage operation (one phase of the three-phase power supply is disconnected), motor winding short circuit or disconnection.
Mechanical failure: pump body jammed (such as impeller stuck by foreign objects), bearing damage, corrosion or deformation of transmission parts.
Other factors: start capacitor damage (for single-phase motor), control circuit failure.
Solution:
Electrical check:
Use a multimeter to measure the power supply voltage to ensure that the voltage is within the rated range.
Check whether the three-phase power supply is balanced, repair broken wires or replace fuses.
Test the motor winding resistance, if abnormal need to repair or replace the motor.
Mechanical inspection:
Disassemble the pump body and remove foreign matter in the impeller or runner.
Check bearing lubrication and replace bearings if necessary.
Check whether the transmission parts (such as coupling, belt) are loose or damaged.
Other measures:
Replace damaged starting capacitors.
Check whether the control circuit (e.g. contactor, relay) is working properly.
2. Insufficient flow or no water during operation
Fault performance:
The pump runs with an abnormal sound, but there is no water at the outlet or the flow rate is significantly reduced.
The pump head is insufficient to reach the expected pumping height.
Possible causes:
Problems with the water source: low water level in the well, clogging of the inlet pipe (e.g. sediment, debris).
Pump body failure: impeller wear or damage, guide casing wear, seal ring clearance is too large.
Piping problems: leakage in the outlet pipe, valve not fully open, excessive pipe resistance.
Solution:
Water source check:
Confirm whether the water level in the well is lower than the suction port of the pump, and reduce the installation depth of the pump if necessary.
Clean the inlet piping to remove sediment or debris.
Pump body overhaul:
Disassemble the pump body, check the wear of the impeller and guide casing, and replace if necessary.
Adjust sealing ring clearance to ensure compliance with design requirements.
Piping inspection:
Check whether there is any leakage in the outlet pipe line and repair the leakage point.
Ensure that the valve is completely open, reduce pipeline elbows and resistance.
3. Excessive vibration or noise during operation
Fault performance:
The pump body runs with obvious vibration, accompanied by abnormal noise.
Prolonged operation may lead to the pump body or pipeline loosening.
Possible causes:
Installation problems: unstable pump body installation, loose foundation.
Mechanical problems: impeller imbalance, bearing damage, drive shaft bending.
Hydraulic problem: Cavitation phenomenon (vaporization of liquid due to low inlet pressure).
Solution:
Installation check:
Retighten the pump body fixing bolts to ensure a solid foundation.
Check the centering of the pump body with the motor and re-center if necessary.
Mechanical overhaul:
Perform dynamic balance test on the impeller, repair or replace the unbalanced impeller.
Replace damaged bearings, check whether the drive shaft is bent, straighten or replace if necessary.
Hydraulic adjustment:
Increase the inlet pressure to avoid cavitation (e.g., reduce the installation depth of the pump).
Check whether there is leakage or blockage in the inlet pipeline.
4. Excessive current or motor overheating during operation
Fault performance:
The motor running current exceeds the rated value, and the motor casing temperature is too high.
Prolonged overload may lead to motor burnout.
Possible causes:
Pump body failure: impeller and pump casing friction, bearing damage, packing too tight.
Piping problems: clogged outlet pipe, valve not fully open.
Electrical problems: power supply voltage is too low, motor winding local short circuit.
Solution:
Pump body overhaul:
Check the clearance between impeller and pump casing and adjust to the design value.
Replace the damaged bearing and adjust the packing tightness.
Piping inspection:
Clean the outlet pipe line and make sure the valve is fully open.
Electrical check:
Measure the power supply voltage and make sure it is within the rated range.
Check the motor winding resistance, repair or replace the short circuit part.
5. Leakage or drop in insulation resistance
Fault manifestation:
Motor casing is energized and insulation resistance test value is below standard.
It may lead to electric shock accident or motor damage.
Possible causes:
Cable damage: broken cable insulation, water in the joints.
Moisture in the motor: water or high humidity inside the motor.
Insulation aging: aging of motor winding insulation material.
Solution:
Cable inspection:
Check whether the cable insulation is broken, repair or replace the cable.
Make sure the cable joints are well sealed to prevent water ingress.
Motor Treatment:
Dry the motor to remove internal moisture.
Re-impregnate the insulating paint to improve insulation performance.
6. Seal leakage
Failure performance:
Fluid leakage from pump body or line connections.
May result in lubricant leakage or well water entering the motor.
Possible Causes:
Damaged seals: mechanical seals or packing seals are aged and worn.
Improper installation: seals are not installed properly or tightened with sufficient force.
Solution:
Replace seal:
Disassemble the seal in the leaking area and replace with a new mechanical seal or packing.
Reinstallation:
Ensure that the seal is installed correctly and that the tightening force is even.
