Electric Motor Maintenance Guide
Electric motors power virtually every piece of equipment in mining operations. Proper motor maintenance prevents unexpected failures and extends motor life. This guide covers essential maintenance tasks for electric motors.
Daily Inspection Tasks
Visual Inspection:
- Check motor housing for damage or corrosion
- Verify motor is clean and free of debris
- Check that cooling fans are unobstructed
- Inspect motor mountings are secure
- Look for signs of overheating (discoloration)
Operational Checks:
- Listen for unusual sounds
- Check for excessive vibration
- Monitor current draw vs. nameplate rating
- Verify thermal protection is functional
Bearing Maintenance
Motor bearing failure is a common cause of motor failure. Proper bearing care extends motor life.
Lubrication Schedule:
- Small motors: Every 2-3 years or per manufacturer
- Large motors: Every 6-12 months
- Motors in harsh conditions: More frequently
Lubrication Procedure:
- Use correct grease type for motor
- Do not over-grease — this damages seals
- Grease until fresh grease emerges
- Run motor briefly to distribute grease
Bearing Replacement:
- Replace when rough, noisy or overheated
- Check shaft and housing fit
- Use proper heating method for installation
- Fill bearing with grease before installing
Electric Motor Maintenance for Mining Equipment
Insulation Testing
Insulation testing (megger testing) checks the condition of motor windings.
When to Test:
- During commissioning
- After repairs or rewinding
- Annually for preventive maintenance
- When problems are suspected
Reading Interpretation:
- > 1000 megohms: Excellent
- 100-1000 megohms: Good
- 10-100 megohms: Fair — monitor closely
- < 10 megohms: Poor — investigate and repair
Troubleshooting Common Problems
Motor Won't Start:
- Check power supply and connections
- Test overload protection
- Check for grounded or shorted windings
- Verify start circuit components
Motor Overheating:
- Check load — motor may be overloaded
- Verify ventilation is adequate
- Check supply voltage is correct
- Inspect for single-phasing condition
Excessive Vibration:
- Check motor alignment with driven equipment
- Inspect motor bearings
- Check for rotor damage or imbalance
- Verify mounting bolts are tight
Excessive Current Draw:
- Motor may be overloaded
- Check for low voltage
- Inspect for mechanical binding
- Test windings for short circuits
WSHT supplies replacement motors and provides motor maintenance support for all major mining equipment brands.
