The Siemens SIRIUS 3RT2926-1BE00-ZX90 is a varistor-type surge suppressor designed for AC control circuits on S0-size contactors. It clips onto the contactor coil terminals, suppressing voltage spikes when the coil de-energizes — protecting downstream PLC outputs and extending contactor life on inductive loads.
Rated for AC control supply voltage at 240 to 400 V at 50 Hz, and 400 to 240 V at 60 Hz. The clip-on fastening method snaps directly onto the S0 contactor's coil terminals — no wiring between suppressor and coil. Dimensions are 12 mm deep, 30 mm wide, 19 mm tall. Mounting position is any orientation.