The Siemens SIRIUS 3RT2946-1CB00 is a surge suppressor built as an RC element, designed to clamp voltage transients across the coil of a contactor. It mounts directly onto the SIRIUS 3RT2.4 contactor family, suppressing inductive kickback that would otherwise shorten coil life or radiate EMI into nearby control wiring. It accepts control supply voltages of 24 to 48 V AC at 50/60 Hz, and 24 to 70 V DC, making it suitable for both AC- and DC-piloted circuits. The RC element is polarity-independent for AC, but for DC applications verify the wiring direction matches the suppressor's internal diode if present — the datasheet's connection diagram is the reference here.
The suppressor measures 25 mm wide, 55 mm high, and 23 mm deep. It clips onto the contactor's coil terminals, so it adds no DIN-rail footprint — the space it occupies is the volume above the contactor itself. No derating curve is listed, so assume full rated voltage across this range unless the contactor's own thermal limits intervene.
No last-time-buy or surplus-channel dependency applies. If you are replacing a failed unit or filling a new BOM line, this is a direct drop-in with no cross-reference needed.