The Siemens SIRIUS 3RT2936-1BC00-ZX90 is a varistor-type surge suppressor designed to clip onto S2 or S3 frame contactors. It handles control supply voltages of 48-127V AC at 50 Hz and 70-150V DC, protecting the coil circuit from voltage transients that would otherwise weld contacts or damage the driver electronics.
Snap-on mounting (clip-on) means it attaches directly to the contactor's coil terminals — no DIN-rail space consumed, no additional wiring for the suppressor itself. The 14.5 mm depth and 30 mm width keep it flush with the contactor profile, so it doesn't eat into panel clearance for adjacent devices.
Active lifecycle status. This is a current-production SIRIUS accessory, not a phase-out or NRND line.