Electronic Variable Speed Drives, 4th Edition

“Total revision” is targeted at maintenance technicians and focused on AC drives.

by Lee Freeland

Electronic Variable Speed Drives, 4th Edition, by Michael E. Brumbach and Jeffrey A. Clade, is a thorough, updated look at variable-frequency drives (VFDs) and their maintenance, operation, installation and more. The 305-page softcover is full of clear drawings and photos and divided into short sections that are well indexed and indicated by bright blue headings. Starting from a short history on legacy equipment, fundamental drive circuits are introduced before more complex drive circuits are presented, all the way through modern digital regenerative drives and frequency inverters.

The original book came into existence to fill a void in learning about the increasingly common electronic VFDs. Though earlier versions of the book focused on DC drives, the gain in popularity of AC drives led the authors to revise it to focus on the latter technology. Today, the AC drive market is expected to continue to grow, while the DC drive market is expected to remain constant.

It is intended for those in or planning to enter the maintenance field. While targeted primarily toward students in two-year technical schools, the book is also considered by the authors as suitable for training in an industrial environment or as an introductory course at four-year institutions. As maintenance technicians must diagnose and repair equipment quickly, the text has been designed to provide, in straightforward language, the material the technician needs to get the job done. Theories of operation have been greatly simplified: few formulae are presented, and those that are are used very simply. An instructor companion site supports book-specific lecture and class tools. In addition, the fourth edition now includes several hands-on activities using the Allen-Bradley PowerFlex® 70 VFD.

Brumbach is associate dean of the Industrial and Engineering Technologies Division at York Technical College in Rock Hill, South Carolina. He holds an associate’s degree in Electronics Technology and is a member of the International Association of Electrical Inspectors; the Instrumentation, Systems, and Automation Society; and the National Fire Protection Association (NFPA). He is also certified by the National Center for Construction Education and Research as a core curricula and electrical instructor. Clade is department chair for the Industrial Maintenance Department at the same college. He holds an associate degree in Industrial Maintenance Technology and is a licensed master electrical contractor in South Carolina.

The authors call the book “a total revision from the third edition.” It begins with a brief history of the variable-speed drive, then moves on to review physical, electrical and motor terminology. The basic theory, installation and setup of a VFD are then covered, followed by VFD installation. An all-new fifth chapter introduces the reader to the many different types of operations a VFD can perform. It begins with theory but also provides several hands-on activities with the PowerFlex VFD, including diagnostics of and troubleshooting with firmware. DC drive theory and troubleshooting follow, with a concluding chapter on servo and stepper motors. Chapter titles are:

• Chapter 1: Introduction to VFDs
• Chapter 2: Review of Physical, Electrical and Motor Terminology
• Chapter 3: VFD Basics
• Chapter 4: VFD Installation
• Chapter 5: VFD Initialization
• Chapter 6: Diagnostics
• Chapter 7: DC Drives
• Chapter 8: Steppers and Servos

Finally, there are three appendices and helpful glossary and index sections. The appendices are intended for review, with the first on basic AC motor theory, the second on basic DC motor theory and the third on rectifiers and power semiconductors. Each chapter concludes with a summary and review questions. It is published by CENGAGE Learning and available at elevatorbooks.com.