Generally accepted methods of protection for ac motors are provided. This guide identi-fies and summarizes the functions necessary for adequate protection of motors based on type, size,and application. This guide does not purport to detail the protective requirements of all motors inevery situation.

This application guide presents generally accepted methods of protection for ac motors. It identifies and summarizes the functions necessary for adequate protection of motors based on type, size, and application. This guide does not purport to detail the protective requirements of all motors in every situation. What it does provide is enough information and guidance for the user to implement adequate protection for particular applications. The recommendations in this guide are based on typical types of installations. However, sufficient background information relating to protection requirements, applications, and setting philosophy is provided to enable the reader to determine required protective functions for motor installation. The protective functions discussed in this guide can also be implemented with multifunction, microprocessor-based protection systems (digital systems). A complete discussion of this type of protection system's attributes is included in this guide. Relay protec...