Schneider Electric’s Square D 1861-S1-R30A is a replacement magnetic coil for Size 0 1861-S1 contactors, designed for 120 VAC operation at 50/60 Hz. The coil energizes the magnetic core to actuate the contactor’s switching in motor-control and starter applications, and is compatible with 9050-B and 9050-R relays, timers, and contactors in the Square D family. It is listed by multiple distributors as 1861-S1-R30A (120 V), including sources like Radwell and Cooper Electric. The R30A suffix identifies the 120 V coil variant used with the 1861-S1 assembly.
