Siemens SIRIUS 3RT2926-1JJ00 — Varistor Surge Suppressor for S0 Contactors
The Siemens SIRIUS 3RT2926-1JJ00 is a varistor-type surge suppressor designed for clip-on mounting onto S0-size contactors in the 3RT2.2 series. The varistor clamps voltage transients from coil de-energization, protecting downstream PLC outputs and control electronics. The LED confirms the suppressor is powered and the varistor junction is intact — a dark LED on an energized coil signals a failed varistor that needs replacement before the next switching event.
This suppressor clips directly onto the front of a SIRIUS S0 contactor — no DIN rail space consumed, no wiring added beyond the existing coil terminals. Dimensions are 12 mm deep, 30 mm wide, and 19 mm high, so it adds negligible projection beyond the contactor face. Mounting position is unrestricted. For a panel already wired with a 3RT2.2 contactor, the 3RT2926-1JJ00 snaps on without rewiring the coil circuit. The varistor bridges the A1-A2 terminals internally; the LED draws a small additional current that the contactor's control transformer must supply.