The Siemens 3RT6926-1CB00 is a SIRIUS RC surge suppressor (snubber) designed specifically for size S0 motor contactors. It clips onto the contactor coil terminals to suppress voltage spikes during switching — the RC coupling absorbs the inductive kick that would otherwise arc across contacts or radiate EMI back into the control circuit. This is the part that keeps a contactor's coil from burning its own auxiliary contacts or coupling noise into a 24 VDC PLC output. Rated for AC/DC control supply voltage, it covers 24 to 70 VDC and 24 to 48 V at 50 Hz (48 to 24 V at 60 Hz). That dual-range means it handles both standard 24 VDC control panels and 48 VAC circuits common in older installations — one part for both, which simplifies spares holding. The 12 mm depth and 30 mm width let it tuck into the S0 contactor's profile without stealing DIN rail space from adjacent devices.
Clip-on fastening to the contactor coil terminals — no tools, no separate wiring.