Variable Frequency Drives

Course Description
The objective of this VFD training course is to build confidence in the student by providing him/her with useful information and practical hands-on exercises
that demonstrate the relevance of the course material.
Course Objective
This course is designed to enable participants to:

• Properly Matching A Drive to A Machine
• Choosing the Correct Motor
• Choosing the Best Type of Variable Frequency Drive (VFD)
• Identify & Correct Drive System Problems
• Identify & Test Major Drive Components
• Perform Start-Up of an AC Drive
• Program & Adjust the Drive for Desired Operation

Course Outline
INTRODUCTION

• Evolution of VFD Control
• Modern Types of Variable Frequency Drives (VFD)

MECHANICAL THEORY

• Horsepower Defined
• Torque Defined
• Example Horsepower and Torque Calculations
• Common Types of Mechanical Loads
• Characteristics of Variable Torque and Constant Torque Loads

BASIC VFD ELECTRICITY THEORY

• Electrical/Hydraulic Circuit Analogy
• Resistance, Voltage, and Current Defined

INTRODUCTION TO AC MOTORS

• Examination of Motor Nameplates and NEMA Designations
• Locked Rotor Current and Full Load Current
• Anatomy of a Motor
• Magnetic Poles and Frequency as Related to Motor Speed
• Torque Characteristics Motors Operated “Across-the-Line”
• Torque Characteristics of Motors Operated on VFDs
• Effects VFDs on Motor Operation and Life Expectancy

PWM AC VFDs

• Common Types of PWM Drives
• Examination of the Main Power Circuit
• Electronic Component Identification
• The PWM Wave Form
• Voltage and Frequency Relationships and Effects on Motor Performance
• Control of Drive System Torque and Horsepower Output
• Torque Output Comparisons of AC Drives VS. Conventional Means of Speed Control
• Standing Wave (Reflective Wave) Phenomena on Motor Cables
• Disassembly of an AC Drive
• Component Identification
• Various Designs of Drives
• Reassemble, Test, Start-Up of AC Drive With Proper Techniques
• Hands-On Programming and Operation of an AC Drive and Motor
• Adjust Minimum and Maximum Speed
• Reset Drive to Factory Defaults
• Adjusting Torque Output
• General Drive Programming
• Methods of Speed and Torque Control

VFD Applications

• Methods of Proper Drive Selection
• Multi-Motor Drive Systems With Example Problem
• Using VFDs to Eliminate Geared Speed Reducers
• Effects of AC Drives on Geared Speed Reducers
• Replacing Mechanical Speed Changers With VFDs

CONCLUSION AND SUMMARY