Repairing a jewelry miniature motor after overload requires first stopping the machine to investigate the cause, and then addressing the issue accordingly. In most cases, overload causes winding overheating, insulation aging, or mechanical component wear. The repair steps are as follows:
1. Power Disconnection and Initial Inspection
Immediately disconnect the power supply to prevent further damage.
Check if the motor casing is hot, has a burnt smell, or is discolored to determine if the coil has burned out.
Check if the connection wires are loose, damaged, or have poor contact to ensure a stable power supply.
2. Check the Status of Core Components
Measure Resistance: Use a multimeter to test the stator winding resistance. If the resistance value is abnormal (too high indicates an open circuit, too low indicates a short circuit), it indicates that the winding is damaged.
Check Brushes and Commutator: For brushed motors, observe whether the brushes are severely worn (less than 2/3 of their original length) and whether the commutator is oxidized and blackened. These can be gently cleaned with fine sandpaper.
Bearing Condition Assessment: Manually rotate the shaft. If it feels sticky or makes abnormal noises, it indicates that the bearing is lacking lubrication or is worn, requiring replacement or lubrication.
3. Common Repair Operations
Clean Internal Dust: Use compressed air or a soft brush to remove dust and oil from the inside of the motor to improve heat dissipation.
Replace Damaged Parts: If the winding is burnt out, try rewinding the coil or replacing it with a completely new stator assembly.
If the brushes are severely worn, replace them with new ones of the same model, ensuring good contact and appropriate pressure.
If the bearing is damaged, it needs to be disassembled and replaced with special tools. Pay attention to alignment and tightening torque during installation.
Lubrication and Maintenance: Add an appropriate amount of high-temperature grease to the bearings and rotating parts to reduce frictional resistance.
