Allen-Bradley 810-A18C Inverse Time Relay is a vintage Bulletin 810 inverse-time current relay designed for overcurrent protection in motor and feeder circuits. It operates with an external current transformer to trip protective devices according to inverse-time current characteristics, enabling coordination with upstream fuses and circuit breakers. The A18C variant identifies a specific model within the 810 family and relies on a mechanical dashpot timing mechanism to produce a time delay that increases as fault current decreases.
