What this surge suppressor does on an S0 contactor
The 3RT2926-1MR00-ZX90 is a SIRIUS surge suppressor — a diode combination with an integrated LED — designed to clip onto Siemens S0-frame contactors. It suppresses the inductive voltage spike when the contactor coil de-energizes, protecting the DC 24 V control circuit from back-EMF that would otherwise arc across the PLC output or relay contact driving it. Rated for DC 24 V control supply voltage, it mounts in any position via a clip-on fastener and fits the standard S0 contactor width of 30 mm and depth of 12 mm — the same footprint as the contactor's own coil terminals.
Active production, no replacement drama
The diode-combination design means it handles DC coil suppression cleanly — the LED gives a quick visual check that the suppressor is powered and the coil circuit is live. The multi-unit packaging (noted in the description) suggests it ships in quantities suited for production runs, not single-piece samples.
Temperature range and panel fit
Operating temperature spans -25 to +60 °C; storage range is -40 to +80 °C. That covers most indoor panel environments and unheated warehouses. The clip-on mount snaps directly onto the S0 contactor without eating extra DIN rail space — the 12 mm depth keeps the assembly tight against the backplane.