Allen-Bradley 810-A11A Inverse Time Current Relay

Allen‑Bradley 810‑A11A Inverse Time Current Relay is a vintage Rockwell Automation device in the Bulletin 810 family, designed to provide inverse‑time overcurrent protection for motors and feeders. The A11A variant specifies a tripping current adjustment range of 25 to 72 A (the related 810‑B11A version covers 23 to 68 A), allowing selection to match motor full‑load currents and protective coordination. As with the broader 810 lineup, it uses inverse‑time current curves to determine trip timing—the higher the overcurrent, the faster the relay trips—an approach documented in Rockwell’s 810 literature and installation manuals. Typical applications include motor protection schemes where short overloads are tolerated without nuisance trips, while sustained overcurrents are reliably interrupted. The Bulletin 810 family encompasses multiple Series variants (A and B) with timing differences described in Rockwell’s installation guides, reflecting decades of use in coordinating with contactors and motor starters in industrial control panels for dependable overload protection.