Achieving IEC type 2 short circuit coordination

Motor control and fuse manufacturers have recently introduced a new term to the North American market that describes the level of short circuit protection provided to the motor starter in a motor branch circuit. That new term is `Type 2 Coordination´. There is a tremendous amount of confusion as to what Type 2 coordination is and how it can benefit users and specifiers of motor starters; the purpose of the authors is to clarify those issues. Specifically, every specifier and user of motor starters must understand: what type 2 coordination is and why it´s important; how Type 2 coordination is achieved; and what benefits result from Type 2 coordination. The tests and pass/fail criteria necessary to satisfy the Type 2 coordination requirements of IEC 947-4-1 are presented. Specific methods for meeting these requirements and a major test program for NEMA and IEC control equipment are detailed