Panel fit and mounting flexibility
The 3RH2122-2BM40 is a SIRIUS size S00 auxiliary contactor — the smallest frame in the family, built for high-density control panels where every millimeter counts. That means you can orient it to fit cable entry paths or clearance around other gear without reworking the rail layout. These are the minimum air gaps to maintain rated isolation — useful when packing multiple contactors side-by-side in a row.
This auxiliary contactor carries 2 NO instantaneous contacts and its current rating varies significantly with the switched voltage — a detail that matters when you're coordinating with PLC outputs or pilot devices running on different control voltages. On the DC side, at 24 V it handles 10 A, but at 220 V DC the rating falls to 1.2 A, and at 600 V DC it's just 0.26 A. The arcing time is 10-15 ms, and the closing/holding power of the DC magnet coil is 4 W. That's built for high-duty applications like conveyor interlocking or machine tool auxiliary circuits where the contactor cycles every few seconds.
Environmental and compliance specs
The substance prohibition date is listed as 10/01/2009, aligning with RoHS and REACH compliance expectations for this generation of SIRIUS gear. The product extension for auxiliary switches is supported, so you can add contact blocks downstream if the 2 NO base isn't enough.