This lesson was designed to provide training for electricians, mechanics, and others, wanting to know more about AC and DC motor maintenance. This library consists of 12 interactive, on-line lessons that address AC and DC motor maintenance. These lessons take approximately 30 to 45 minutes to complete.

Introduction to AC Motor Maintenance


Records, Tools, and Instruments


Preventive AC Motor Maintenance


Measurement in Preventive AC Motor Maintenance


Preparing for Periodic AC Motor Maintenance


Motor Disassembly and Reassembly in Periodic AC Motor Maintenance


Corrective Maintenance for AC Motors


Introduction to DC Motor Maintenance


Commutator Inspection


Commutator Wear


Commutator Maintenance


Brush Maintenance

• Identify characteristics of a motor maintenance program.
• Identify types of motor maintenance.
• Identify safety procedures to use during motor maintenance.

• Identify reasons for having a record keeping system.
• Identify categories of information for a record keeping system.
• Select the appropriate motor maintenance tools and instruments for given tasks.

• Identify characteristics of preventive motor maintenance.
• Inspect a motor for general maintenance and for identifying problems.
• Clean and lubricate a motor as warranted by a preventive maintenance inspection.

• Explain the need for taking measurements in preventive motor maintenance.
• Explain the importance of comparing measurement readings.
• Take current measurements in preventive motor maintenance.
• Explain the causes of current variation in an AC motor.
• Take temperature measurements in preventive motor maintenance.
• Explain the causes and effects of excessive temperature in an AC motor.
• Take vibration measurements in preventive motor maintenance.
• Explain the causes of vibration in an AC motor.

• Identify characteristics of periodic motor maintenance.
• Identify the major components of an AC motor.
• Perform pre-maintenance testing: Winding insulation resistance.
• Perform pre-maintenance testing: Winding resistance.

• Describe how to properly disassemble an AC motor for periodic motor maintenance.
• Disassemble an AC motor.
• Identify the proper way to clean a disassembled AC motor.
• List the various AC motor parts and what to look for during inspection.
• Describe how to reassemble an AC motor.
• Reassemble an AC motor.
• Describe how to perform post-maintenance testing.

• Identify causes and corrective actions for a motor that wont start.
• Identify causes and corrective actions for a motor with abnormal noise.
• Identify causes and corrective actions for a motor overheating.
• Identify causes and corrective actions for a motor with overheated bearings.

• Identify similarities between AC and DC motors.
• Identify the difference between AC and DC motors.
• Identify components of a DC motor commutator and their function.
• Identify factors that affect commutation.

• Describe the color of the commutator and explain the function of the oxide film.
• Identify the causes of high mica and corrective actions.
• Identify the causes of uneven segments and corrective actions.
• Identify the causes of thrown solder and corrective actions.

• Identify wear patterns, their causes, and corrective actions.
• Identify the causes of arcing and corrective actions.
• Identify the causes of high mica and corrective actions.

• Explain how to prepare a commutator for reconditioning.
• Explain how to undercut the mica of a commutator.
• Describe how to clean and check the commutator after maintenance.
• Explain the purpose of performing a commutator run-in procedure.

• Describe how to inspect various aspects of a brush.
• Identify the factors to be considered when selecting a brush.
• Identify the procedures for cleaning and inspecting the brush holders.
• Identify the steps involved in setting the height of a brush holder.
• Identify the procedure for installing brushes.
• Explain how to seat brushes.
• Explain how to adjust spring pressure.