Allen-Bradley 809-A12E Instantaneous Trip Current Relay

The Allen-Bradley 809-A12E Instantaneous Trip Current Relay is a magnetically operated device used in motor protection circuits to trip when the sensed current exceeds a preset limit, and it belongs to Rockwell Automation’s Bulletin 809 family of Quality Instantaneous Trip Relays. The A12E variant provides an adjustable trip setting in the 38–108 A range, enabling precise tailoring to a motor or feeder’s protection requirements. It supports use in both AC and DC applications, with reset points typically at 70–85% of the trip setting for AC and 62–82% for DC, providing stable operation after a fault condition. Common applications include rapid overcurrent protection for industrial motors and power feeders where instantaneous disconnection is required to prevent damage or nuisance tripping.