Trip Class is a standardized rating system defined by IEC 60947-4-1 and NEMA standards that specifies the maximum time a motor protection device (thermal overload relay or motor protection circuit breaker) will take to trip and disconnect a motor when subjected to 600% (or 7. REM615 is a member of ABB's Relion ® product family and part of its 615 protection and control series of relays. Understanding each setting facilitates proper relay coordination. These relays are designed to detect excessive current—usually caused by mechanical overload or voltage imbalance—and cut off power to the motor before it overheats and suffers.