Eaton Cutler-Hammer D40RBA Power Reed Relay Module

The Eaton Cutler-Hammer D40RBA is a 120 V coil, Type R power reed relay designed for compact, fast-acting switching in industrial control and automation circuits, using sealed reed contacts to provide reliable isolation and rapid actuation in space-constrained panel installations. Belonging to Eaton’s D40 family, the D40RBA is specified for operation with input signals at frequencies between 50 and 400 Hz, a common range for control and signaling applications, and is marketed as a 120 V coil reed relay. Retail listings for the D40RBA emphasize its coil voltage of 120 V and identify it explicitly as a Type R reed relay, underscoring its role as a compact, coil-driven device intended to switch small electrical signals quickly. Because it is a dedicated replacement component in Eaton’s legacy Cutler-Hammer relay lineup, the D40RBA is suited for use in legacy equipment and control panels where discrete relays are preferred for direct, fast switching without complex electronics.