The Siemens 3RT2926-1JL00-ZX90 is a SIRIUS surge suppressor — a varistor with integrated LED indicator — designed to clip onto size S0 contactors. It handles AC control supplies from 127 to 240 V at 50/60 Hz and DC supplies from 70 to 150 V, making it a single-component fit for most standard S0 coil voltages in motor starter assemblies.
Mounting is clip-on — no tools, no extra DIN-rail footprint. The suppressor snaps directly onto the contactor front, adding just 12 mm depth, 30 mm width, and 19 mm height to the assembly. Any mounting position works, so it fits tight enclosures and vertical bus stacks without derating.
Lifecycle status is Active — Siemens lists this as current production. No last-time-buy or phase-out notice is published.
The varistor design clamps inductive voltage spikes from the contactor coil, protecting PLC outputs and control-circuit components. The LED gives a quick visual check that the suppressor is powered — useful during panel commissioning and fault isolation. RoHS compliance date is noted as October 1, 2009, meeting EU substance restrictions.