Analysis of the damage of three-phase AC servo motor - News - Global IC Trade Starts Here.

Three-phase AC servo motors are widely used in industrial automation due to their high precision and efficiency. However, after prolonged operation, various faults can occur. Promptly identifying the root cause of these issues and implementing appropriate solutions is essential for preventing further damage and ensuring the smooth operation of the equipment.

1. After turning on the power, the motor does not rotate, but there are no unusual noises, smells, or smoke.

1. Possible causes: 1) The power supply is not properly connected (at least two phases are open); 2) A fuse is blown (at least two fuses are damaged); 3) The overcurrent relay is set too low; 4) There is an error in the control wiring.

2. Troubleshooting steps: 1) Inspect the power circuit switch and check for any breaks in the fuse or junction box; repair as needed. 2) Verify the fuse type and replace it if necessary. 3) Adjust the relay setting to match the motor's specifications. 4) Correct the wiring connections.

2. Motor does not start after power is applied.

1. Fault reasons: 1) The rotor winding has an open circuit (one phase disconnected) or the power supply is out of phase; 2) The winding leads are incorrectly connected or the winding is internally reversed; 3) The contact in the power circuit is loose, causing high resistance; 4) The motor load is too heavy or the rotor is jammed; 5) The power supply voltage is too low; 6) The small motor assembly is too tight or the bearing grease is too hard; 7) The bearing is stuck.

2. Troubleshooting: 1) Locate and repair the open circuit. 2) Check the winding polarity and confirm that the ends are correctly connected. 3) Tighten the wiring screws and use a multimeter to detect false connections. 4) Reduce the load or fix mechanical issues. 5) Confirm the correct connection method and ensure the power cable is not too long. 6) Reassemble the unit and replace the grease with a suitable one. 7) Repair or replace the bearing.

3. Motor starts with difficulty, and the speed under rated load is lower than expected.

1. Causes: 1) Power supply voltage is too low; 2) The motor is connected incorrectly; 3) The rotor winding is open or broken; 4) The local coil is misconnected or reversed; 5) The number of turns in the winding is incorrect; 6) The motor is overloaded.

2. Solutions: 1) Measure the power supply voltage and try to increase it. 2) Correct the connection method. 3) Inspect the winding for breaks and repair them. 4) Identify and fix any misconnections. 5) Restore the correct number of turns. 6) Reduce the load if possible.

4. No-load current is unbalanced, with large differences between the three phases.

1. Reasons: 1) The winding end is connected incorrectly; 2) The power supply voltage is unbalanced; 3) There is a fault in the winding, such as a turn-to-turn short or a reversed coil.

2. Fixes: 1) Check and correct the winding connections. 2) Measure the power supply voltage and eliminate any imbalance. 3) Address the winding issue by repairing or replacing affected sections.

5. During operation, the motor makes abnormal sounds or noise.

1. Causes: 1) Worn bearings or foreign materials in the lubricant; 2) Loose rotor core; 3) Lack of lubrication in the bearings; 4) High or unbalanced power supply voltage.

2. Solutions: 1) Replace the bearing or clean it thoroughly. 2) Repair the rotor core. 3) Add lubricating oil. 4) Check and adjust the power supply voltage to ensure stability.

6. The motor vibrates excessively during operation.

1. Fault causes: 1) Excessive bearing clearance due to wear; 2) Uneven air gap; 3) Rotor imbalance; 4) Shaft bending; 5) Poor alignment between the coupling (pulley) and motor.

2. Troubleshooting: 1) Repair or replace the bearing if necessary. 2) Adjust the air gap to be even. 3) Balance the rotor dynamically. 4) Straighten the shaft. 5) Recalibrate the coupling to meet the required alignment standards.

7. Bearings overheat during operation.

1. Causes: 1) Too much or too little lubricant; 2) Poor-quality grease with impurities; 3) Misalignment of the bearing with the journal or end cap; 4) Eccentric inner hole of the bearing, causing friction with the shaft; 5) The motor end cap or bearing cover is not flat; 6) Poor alignment between the motor and load or overly tight belt; 7) Incorrect bearing clearance; 8) Bent motor shaft.

2. Fixes: 1) Add the proper amount of grease (1/3–2/3 of the bearing volume). 2) Replace the grease with clean, high-quality lubricant. 3) Adjust the fit by grinding or reassembling. 4) Repair the bearing housing to remove rubbing points. 5) Reassemble the unit. 6) Recalibrate and adjust the belt tension. 7) Replace the bearing. 8) Straighten the motor shaft or replace the rotor.

8. The motor becomes overheated and may emit smoke.

1. Fault causes: 1) High power supply voltage; 2) Low power supply voltage leading to excessive current and overheating; 3) Improper thermal disassembly during winding repair, causing iron core damage; 4) Overloading or frequent starting; 5) Phase loss causing two-phase operation; 6) Inadequate insulation coating during rewinding; 7) High ambient temperature, dirty motor surface, or blocked air ducts.

2. Solutions: 1) Lower the power supply voltage. 2) Increase the voltage or use thicker cables. 3) Repair the iron core. 4) Reduce the load and limit the number of starts. 5) Restore three-phase operation. 6) Apply proper insulation coatings using secondary dipping and vacuum processes. 7) Clean the motor and improve ventilation.