1. Electric Motor Monitoring & Life Prediction in Mining Ben Nalbantof Supervisor – Galina Mirzaeva Cooperative Research Centre (CRC) for Mining

2. Objectives Existing methods of motor wellness diagnostic Determine physical conditions causing DC motor faults Identify excessive wearing & damage to their elements Diagnose any unreliable operations Recognise causes of lifetime reduction Modify existing operations and maintenance procedures

3. Motivation Mines desire an improvement in equipment performance & asset utilization Existing motor fleets are extensive

4. DC Motor Armature Brushes Commutator

5. Project Scope Insulation Commutation Switching Drive Interference

6. Insulation Insulation resistance Polarization Index Impulse Testing Insulation Testing DC coil resistance High Potential Partial Discharge Impulse Testing Most involved of the techniques Steep voltage front impulses test insulation

7. Commutation Armature Reaction Commutation Process Causes of Sparking Methods of mitigating sparking issues

8. Armature Reaction

9. Commutation Armature Reaction Commutation Process Causes of Sparking Methods of mitigating sparking issues

10. DC Machine Testing Achievements & Plans Efficiency Tests Armature Fault Tests Commutation Tests

11. Achievements & Plans Excitation of DC motor for testing

12. Switching Electronics Interference Thyristor Drive

13. Simoreg DC Drive Different switching frequencies Vary di/dt Other available options

14. Conclusions DC motors review Insulation tests DC motor testing DC motor testing with drive attached Results and recommendations

15. Questions?