AC motors can be repaired, but it is necessary to make a comprehensive judgment based on the type of fault, degree of damage, service life, and maintenance cost of the motor.

1、 The core conclusion of “repairability” of AC motors
The core structure (stator, rotor, winding, bearings, etc.) of AC motors (such as asynchronous motors, synchronous motors, etc.) are all repairable or replaceable components, and there is no “absolutely irreparable” situation, but two prerequisites must be met:
Core components (such as stator core and rotor shaft) have not suffered irreversible damage (such as severe deformation, fracture, or burning to the point of irreparable damage);
The maintenance cost is lower than replacing a new motor (especially for low-power and old motors, cost-effectiveness needs to be balanced).
2、 Common faults and corresponding maintenance methods of AC motors
The difficulty and cost of repairing different faults vary greatly, and the following are the most typical situations:

Fault Type: Bearing wear/damage , abnormal noise, high vibration, and overheating of the end cover during operation

Repair method: Replace bearings of the same model (pay attention to bearing accuracy and installation clearance)

Fault Type: Winding damp/slight short circuit, low insulation resistance, difficult start-up, and localized heating during operation

Repair method:  Winding drying (when damp), repairing short circuit points (when slightly short circuited)

Fault Type: Winding burnout (partial/overall),  there is a burnt smell, tripping, and the motor cannot start

Repair method: Dismantle the old winding, rewire (matching the original winding parameters: wire diameter, number of turns, wiring method), immerse in paint and dry

Fault Type: Loose/damaged wiring terminals, after power on, the motor does not rotate and the terminal heats up/ignites

Repair method: Tighten terminals and replace damaged terminal posts/boards

3、 Key considerations for communication motor maintenance
Diagnose first, then decide whether to repair or not
Before repair, it is necessary to use professional tools such as multimeters, insulation resistance meters, clamp ammeters, and vibration testers to identify the root cause of the fault and avoid blind disassembly (for example, “motor not turning” may be a wiring problem rather than internal component damage, and does not require complex repairs).
Performance verification is required after repair
After repair, testing must be conducted to ensure safety and performance standards, with a focus on verifying:
Insulation performance: Use an insulation resistance meter to measure the insulation resistance of the winding to ground and between windings (usually required to be ≥ 0.5M Ω, with higher requirements for high-voltage motors);
Operating parameters: whether the current, speed, and temperature rise during no-load operation are normal, and whether there are any abnormal noises or vibrations;
Load performance: Whether it can operate stably after being loaded, and whether the current is within the rated range.
Low power motors: prioritize cost-effectiveness
For small AC motors with a power of ≤ 1.5kW (such as household fan motors and small water pump motors), if complex faults such as winding burnout occur, the maintenance cost (including labor and materials) may be close to or even exceed the price of a new motor. At this time, it is recommended to directly replace the new motor to avoid the repeated cost of “repairing and breaking”.
High power/special motors: priority for professional maintenance
For industrial grade high-power motors (such as 10kW and above), explosion-proof motors, variable frequency motors, etc., due to the high precision requirements of core components (such as high-temperature resistant windings and explosion-proof enclosures), it is necessary to find a qualified maintenance manufacturer (such as holding explosion-proof maintenance qualifications) to avoid safety hazards caused by non professional maintenance (such as explosion-proof performance failure and insulation level not meeting standards).