Amazon.com description: Product Description: Variable Frequency Drives – Installation & Troubleshooting! This book has been written with one thing in mind, to explain in plain language what VFDs are, how they function, how to install and program necessary parameters, and how to troubleshoot and use fault code diagnostics. These discussions are a must have for every technician who wants to develop a solid understanding of Variable Frequency Drives and Pulse Width Modulation. Written by a technician for other technicians, Mr. Anderson focuses on areas of discussion that are relevant to the main objective – learning how to troubleshoot and quickly resolve drive problems. Contains easy to understand diagrams and test procedures.