AC Variable Frequency Drives Maintenance & Troubleshooting

Course Description

This hands-on training event is designed to provide personnel that work with Variable Frequency Drives (VFD) a practical used understanding of AC motors and VFDs. Hands-on lab exercises are used throughout the workshop to simulate actual plant conditions. Course hardware will include a variable frequency AC motor drive workstation. A digital multi-meter is provided and students may bring one to be used in the class. A 4-20mA current loop simulator and clamp on current meter are also available.

Topical Outline

  • Why use a Variable Frequency Drive
    - Variable and constant torque drives
  • Motor Fundamentals
    - Motor Construction and Operation
  • Variable Frequency Drives
    - Power, motor and control wiring
    - Menu System
    - Display unit
  • AC Motor Speed Control
    - Starting, running and stopping a motor
    - Use drive status and correct errors to allow the motor to turn
  • Control Circuits
  • Troubleshooting
    - Be sure direction, speed reference and enable are set.



Course Length

16 hours


Persons completing this course will be able to:

  • Explain basic AC motor operation
  • Identify motor parts and connections
  • Describe variable speed motor control
  • Check the power, control and motor wiring to the drive
  • Use the internal menu, edit parameters and configurations
  • Save and recall drive profiles
  • Check for proper operation of 4-20 mA current loop
  • Read any error codes and take corrective action
  • Check the status of the drive
  • Proper method to change a drive