Specialist

Introduction to Variable Frequency Drives

Course summary

Variable Frequency Drives (VFDs) are widely used across industry to provide efficient and flexible control of AC motors. As their use has increased, engineers and technicians are increasingly required to understand how drives operate, how they are configured and commissioned, and how to identify and resolve common faults.

This course will give you the fundamental skills and knowledge needed to understand, operate, commission and carry out first-line fault finding on Variable Frequency Drives and their associated motor systems.

The course combines essential theory with practical, hands-on exercises to take you through the principles of AC motors and variable speed control, the construction and operation of a VFD, and the key considerations when selecting, installing and configuring a drive for an industrial application.

You will benefit from presentation sessions and practical exercises using VFD and motor training equipment. These will include interpreting motor nameplate information, identifying drive components and connections, entering motor data, configuring operating parameters, setting acceleration and deceleration times, establishing local and external control, configuring speed references, monitoring drive operation and diagnosing common faults.

Course itinerary

Introduction What is a VFD? Common terminology: VFD, VSD, inverter and drive. Typical industrial applications. Benefits and limitations of variable-speed operation.
AC motor fundamentals Three-phase induction motor principles; rotating magnetic field; synchronous speed; poles, frequency and speed; slip; torque; motor nameplate information; star/delta connections.
Motor starting methods Common motor starting methods; Direct-On-Line (DOL), Star-Delta, Primary or stator resistance starter.
VFD fundamentals Basic VFD block diagram; rectifier, DC link and inverter stages; PWM; changing motor voltage and frequency; V/f control; introduction to vector control; acceleration and deceleration.
Drive selection & installation Basic drive and motor sizing; supply requirements; overload considerations; environmental factors; enclosure/IP rating; ventilation and cooling; cable considerations; earthing and EMC.
Practical 1 Identify drive components and terminals; identify motor data; make basic drive/motor connections on a training rig; navigate the drive keypad; enter motor nameplate data; set minimum/maximum frequency and acceleration/deceleration times.

Control & configuration Local vs remote control; start/stop arrangements; digital inputs; analogue inputs; speed references; relay/digital outputs; introduction to industrial communications; presets and basic application functions.
Motor control in practice Starting and stopping; ramps; current limits; torque considerations; braking methods; controlled stopping; behaviour of loads such as pumps, fans and conveyors.
Fault finding Drive status information; alarms vs trips; overcurrent, overvoltage, undervoltage, overload and overtemperature; motor and wiring faults; incorrect parameters; systematic troubleshooting; safe use of test equipment.
Practical 2 Configure external start/stop controls and a speed reference; operate a motor over a defined speed range; monitor current/frequency/status; introduce simulated faults; diagnose faults from symptoms and drive codes; restore correct operation.
Theory test Short written/multiple-choice assessment covering motor fundamentals, VFD principles, installation, parameters, control methods, safety and fault finding.

Programme may be subject to amendment.

 

 

 

 

Why attend?

  • Understand the fundamental operating principles of Variable Frequency Drives and three-phase AC motors.
  • Understand how a VFD controls motor speed and torque by varying frequency and voltage.
  • Identify the main components of a VFD and understand the function of the rectifier, DC link and inverter stages.
  • Interpret motor nameplate information and use it to configure essential drive parameters.
  • Set up and commission a VFD, including motor data, speed limits, acceleration and deceleration times.
  • Configure local and external start/stop controls, digital inputs and analogue speed references.
  • Monitor drive operating information and recognise common alarms and trip conditions.
  • Apply a systematic approach to diagnosing common VFD, motor, control and parameter-related faults.
  • Gain practical experience configuring, operating and fault-finding a VFD-controlled motor system.

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