Variable Frequency Drives

Table of Contents

• 1 Introduction
  • a. Scope of the Variable Frequency Drive
  • b. Overview of Variable Frequency Drives
  • c. Economics
• 2 Classifications of Drives
  • a. AC Drives
  • b. Other AC Drives
  • c. DC Drives
  • d. Eddy Current Clutches
  • e. Advanced Motors
  • f. Mechanical Speed Control
• 3 Principles of Operation - AC VFD Drives
  • a. AC Induction Motors
  • b. Squirrel Cage AC Induction Motors
  • c. Pulse Width Modulated Variable Frequency Drives
• 4 Selection of VFD Drives
  • a. Electrical Considerations When Applying VFD to AC Motors
  • b. Motor Considerations
• 5 Application considerations and estimated Savings for VFD Drives
  • a. Driven Load Characteristics and Power Requirements
  • b. Comparison with Conventional Control Methods
  • c. Monitoring and Verification
  • d. System Efficiency
  • e. Electrical Efficiency
  • f. Cost Per Unit Product
  • g. Reliability and Maintenance
• 6 Case Studies
  • a. Case Study: Replacement of Eddy-Current Drive with a VFD
  • b. Case Study: Replacement of Damper Controls with VFDs in an HVAC System
  • c. Case Study: Replacement of Vacuum Pump Controls with a VFD in a Dairy Facility
• Appendix A: Bibliography
• Appendix B: Useful Web Sites
• Appendix C: Industry Acronyms and Glossary Of Terms
• Appendix D: Useful Formulas
• Appendix E: Conversion Factors