Application of Inherent Thermal Protection to Industrial Motor Systems

The operation of integral horsepower motors in typical industrial applications presents unique problems requiring protective functions which go beyond those available with conventional systems. Because machine downtime results in one of the industry's most perplexing economic problems, it has become imperative that fault conditions be identified on a continuing basis. An expandable electronic system is described which not only provides protection for the motor and driven equipment but also allows the maximum safe utilization of the motor's overload capability. The compatibility of this system with the National Electrical Code requirements is also discussed.