Motors, Variable Speed Drives and Generators: Selection, Applications, Operation, Diagnostic Testing, Maintenance and Troubleshooting Course

Course Overview:

This course fully describes how variable speed drives (VSDs) are controlled, installed, selected, troubleshot, and linked to systems, such as PLCs. 

They will also appreciate flux-vector control features, squirrel cage induction motors, VSDs protective systems. Winding topics are: torque-speed curves and power electronic converters, management of harmonics, EMC/EMI problems, and motor burning prevention. 

This course targets engineers, technicians and plant maintenance personnel to help them optimize VSD characteristics, install them in the right way and deal with their industrial applications. In addition, practical exercises and the use of fault-finding techniques are included.

Course Objectives:

At the end of this workshop participants will be able to:

• Demonstrate a sound understanding of how AC Variable Speed Drives (VSD's) work
• Install VSDs properly
• Select the right VSD for a given application
• Troubleshoot VSDs competently
• Competently explain how flux-vector control works for drive applications
• Understand squirrel cage induction motors
• Identify the protection and control system requirements for VSD's
• Interface VSD’s with PLCs
• Understand the causes of motor burnout
• Deal effectively with VSD harmonics and EMC/EMI problems

Who Should Attend?

This program is designed for instrumentation, control, electrical/electronic engineers and technicians, maintenance personnel, plant technical staff, and supervisors.

Course Outlines:

Control System for AC Variable Speed Drives

• The Overall Control System
• Power Supply to the Control System
• DC Bus Charging System
• VSD Control Loops (Open-Loop, Closed-Loop)
• Vector control and its applications
• Current Feedback in AC Variable Speed Drives
• Speed Feedback from the Motor

Introduction to Variable Speed Drives

• The Need for Variable Speed Drives
• Fundamental Principles of Speed Control
• Efficiency, Torque, Inertia, Horsepower/Power Factor
• Torque-Speed Curves
• How the motor produces Torque
• Types of Variable Speed Drives

The Selection of Ac Converters For Variable Speed Drive Applications

• The Basic Selection Procedure
• Load ability of Converter Fed induction Motors
• Operation in the Constant Power Region
• The Nature of the Machine Load
• Starting and Stopping VSDs (Motor Braking)
• How to Calculate Acceleration Torques and Times
• How to select the correct Motor and Converter for Pump and Fan Loads
• How to select the correct Motor and Converter for Constant Torque Loads, such as conveyors
• Summary of the Selection Procedure

Installation and Fault Finding Techniques

• General Installation and Environmental Requirements
• Power Supply Connections and Earthing
• Where to install the Contactors in the Power Circuit
• Installing AC Converters into Metal Enclosures

Phase AC Induction Motors

• Basic Construction and Physical Configuration
• Principles of Operation and Performance
• Equivalent Circuit and Fundamental Equations
• Starting, Acceleration, Running and Stopping
• Power, Torque and Thermal Rating

Power Electronic Converters

• Definitions and Basic Principles
• Power Diodes and Thrusters
• Principles of Communication
• Power Electronic Rectifiers
• Power Electronic Inverters
• Gate Commutated Converters
• Gate Controlled Devices - GTO, FCT, GTR, FET, IGBT

Electromagnetic Compatibility (EMC)

• Sources of Electromagnetic Interference
• Harmonics on the Power Supply side of AC Converters
• The Effect of Harmonic Distortion on other connected Equipment
• Methods of reducing the effect of Supply side Harmonics
• Electric Motor Protection
• Thermal Overload Protection – Current Sensing
• Thermal Overload Protection – Direct Temperature Sensing

Protection of Motors and Converters

• AC Frequency Converter Protection
• Fault Diagnostics
• Electric Motor Protection
• Thermal Overload Protection – Current Sensors
• Thermal Overload Protection – Direct Temperature

Special Topics

• PWM Rectifier for AC Converters
• Soft Switching
• The Matrix Converter