Allen-Bradley 809-A03E Instantaneous Trip Relay

Allen-Bradley 809-A03E Instantaneous Trip Current Relay is a magnetically operated, instantaneous overcurrent relay (Bulletin 809) in an Open Type configuration designed for fast tripping in electrical protection circuits. It accepts a 4 A coil and provides an adjustable trip current range of 2.1–6.1 A on AC applications and 1.9–5.7 A on DC, with a 50/60 Hz operating frequency and a maximum rating of 600 VAC or 600 VDC. When the current exceeds the setting, the relay triggers to interrupt the circuit; reset occurs at about 70–85% of the trip setting for AC and 62–82% for DC. The A03E variant is one of the standard instantaneous trip relays in the 809 family and is typically used in motor protection and power-distribution schemes where rapid disconnection on fault current is required. Note that this model was listed as discontinued by the manufacturer as of February 27, 2010, though units may still be available from third-party distributors.