I. Overheating of the matching power motor

Firstly, power supply issues: High or low voltage; under specific loads, voltage fluctuations exceeding the rated value by 10% to -5% can cause motor overheating; three-phase voltage asymmetry; if the three-phase voltage imbalance exceeds 5%, it will lead to winding overheating; phase loss operation; experience shows that over 85% of agricultural motor burnouts are caused by phase loss operation; a phase loss protection device should be installed on the motor. Secondly, pump issues: Mismatched power (too small a motor for the load), causing the motor to overheat due to prolonged overload operation; frequent starts; motors rated for short-time or intermittent operation are used continuously. The number of starts should be limited, and appropriate thermal protection should be selected and used according to the rated values marked on the oil-filled submersible pump motor. Thirdly, motor issues: Incorrect wiring (e.g., delta connection mistaken for a wye connection), causing a rapid increase in motor temperature; inter-turn short circuits, turn-to-turn short circuits, or partial grounding in the stator winding; minor issues cause local overheating, while severe issues cause insulation failure; broken bars or defects in the squirrel cage rotor, causing a rapid increase in core temperature after 1-2 hours of operation; system failures; check if the fan is damaged, the rotation direction is correct, and the ventilation holes are unobstructed; bearing wear, rotor eccentricity, and rubbing between the stator and rotor cores produce metallic impact sounds, causing a rapid increase in core temperature; in severe cases, the motor may smoke or even the coils burn out. Fourthly, working environment issues: Moisture in the motor windings or dust, oil, etc., adhering to the windings, reducing insulation. Measure the insulation resistance of the motor and clean and dry it; excessively high ambient temperature. When the ambient temperature exceeds 35℃, the high intake air temperature will cause the motor temperature to be too high; improve the working environment, such as using a shed for sunshade. Note: For electrical faults, repairs should be carried out by electricians with professional qualifications. Those with insufficient knowledge should not attempt repairs to prevent personal injury accidents.

II. Insufficient Flow Rate

This is due to: Mismatched motor speed or belt slippage, resulting in low speed; too small an installation angle of the axial flow pump blades; insufficient head, too long pipelines, or pipelines with right-angle bends; high suction head; blockage of the bottom valve, pipeline, or impeller, or impeller damage; serious leakage in the discharge pipe. Troubleshooting: Restore the rated speed, clean the belt oil and dirt, adjust the blade angle, lower the pump installation position, shorten the pipeline or change the curvature of the pipeline; seal the pump leaks, tighten the fittings; remove blockages, replace the impeller; replace the leakage ring, seal the leaks.

III. Pump Overheating

Causes: Bearing damage; too small a gap between the rolling bearing or bracket cover; bent submersible sewage pump shaft or misalignment of the two shafts; belt too tight; lack of oil or poor oil quality; blockage of the balance hole on the impeller, causing the impeller to lose balance and increase the thrust to one side. Troubleshooting: Replace the bearings; remove the rear cover and install shims between the bracket and bearing housing; check the pump shaft or adjust the concentricity of the two shafts; adjust the belt tension appropriately; add clean grease, filling about 60% of the bearing space; clear the blockage in the balance hole.

IV. Failure to Start

First, check the power supply: Check the firmness of the connections; check the tightness of the switch contacts; check if the fuse is blown; check if the three-phase power supply is equal. If there is a break, poor contact, blown fuse, or phase loss, identify the cause and repair it promptly. Then check for mechanical failures in the pump itself. Common causes include: Packing too tight or impeller blocked by debris; pump shaft, bearings, and leakage rings rusted; severely bent pump shaft, etc. Troubleshooting: Loosen the packing, clear the inlet channel; disassemble the pump body to remove debris and rust; remove and straighten or replace the pump shaft.

V. Inability to Prime

The cause is air in the pump or water intake pipe, or the bottom valve is not tightly closed, the water intake is not full, the vacuum pump packing is severely leaking, or the gate valve or flap valve is not tightly closed. Troubleshooting: First, pressurize the water, then fill the pump body with water, and then start the machine. At the same time, check if the check valve is tight, and if there are any air leaks in the pipeline and joints. If air leaks are found, disassemble and apply lubricating oil or putty to the joints, and tighten the screws. Check the oil seal ring of the pump shaft; if it is severely worn, replace it with a new one. Pipeline water or air leaks. The nuts may not have been tightened during installation. If the leakage is not serious, apply cement or asphalt-mixed cement slurry to the leaking area. For temporary repairs, apply wet mud or soft soap. If the leak is at the joint, tighten the nuts with a wrench; if the leak is serious, it must be disassembled and reassembled, and cracked pipes must be replaced; lower the head and submerge the pump outlet 0.5m underwater.

VI. Severe Vibration

The main reasons are: Unbalanced motor rotor; poor coupling connection; bearing wear and bending; loose or broken parts in the rotating parts; unstable pipeline supports, etc. Solutions include adjustment, repair, reinforcement, and straightening.