The Siemens 3RT2926-1JL00 is a SIRIUS varistor-type surge suppressor with an integrated LED indicator, designed to clip onto S0-size contactors in the 3RT2.2 family. It suppresses voltage spikes across the coil when the contactor de-energizes — the varistor clamps the inductive kickback, protecting nearby PLC outputs and control relays from overvoltage damage. The LED gives a quick visual check that the suppressor is powered and the coil circuit is live.
Rated for AC coils at 127–240 V (50/60 Hz) and DC coils at 70–150 V, this single part covers the common 230 V AC and 110 V DC control voltages found across European and North American panel designs. The AC range is specified separately at 50 Hz and 60 Hz — the 127–240 V window holds for both line frequencies, so no derating or variant swap is needed when a panel ships to a 60 Hz site. The DC range starts at 70 V, meaning it suits nominal 110 V DC control buses common in process plants and substations.
Physical fit — clip-on to S0, 12 mm deep
Mounts by clip-on directly to the front of a S0-size contactor — no tools, no wiring between the suppressor and the coil terminals. The body measures 30 mm wide, 19 mm high, and only 12 mm deep, so it adds negligible depth to the contactor assembly. In a dense DIN-rail panel, that 12 mm projection keeps the contactor row within the standard 60 mm enclosure depth. Mounting position is unrestricted, so it works in vertical or horizontal rail orientations without derating.