A New Approach to VFD System Specifications and Rebates

Variable frequency drives (VFDs) are used to provide flexibility and efficiency enhancements for agricultural pressurized irrigation systems. Standard 6-pulse VFDs commonly used for agricultural pumps can also create real problems with the pump motor and nearby electrical systems, unless mitigated by special equipment. With support by the California Polytechnic State University (Cal Poly) Irrigation Training and Research Center (ITRC), Pacific Gas and Electric Company (PG&E) recently began a new rebate program for installing VFD systems for pressurized irrigation. A major component of the new rebate program is the requirement to comply with a detailed set of minimum VFD system design and installation specifications. It was recognized that specifications were needed for farmers to receive comparable quotes for a good-quality VFD system, without needing to know all the technical details. Instead of a more typical qualified product list, which requires continuous time and effort to maintain, the specifications focus on minimum performance-based criteria and therefore provide flexibility for the VFD system designer. This paper provides an overview of the specifications’ content and rebate program implementation