Auxiliary contactor for control-circuit switching
The Siemens 3RH2122-2FB40-1AA0 is a SIRIUS auxiliary contactor in frame size S00, designed for switching control circuits rather than main motor loads. It carries 2 normally open instantaneous contacts, making it suitable for interlocking, signalling, or extending the auxiliary contact count on a larger contactor or starter assembly. The coil is rated 24 VDC and includes an integrated diode as the surge suppressor, which clips the inductive kickback when the coil de-energises — critical for protecting the PLC output or relay that drives it. Closing power of the magnet coil is 4 W at DC.
The contact ratings vary significantly with the switched voltage and current type.
The contactor measures 45 mm wide, 70 mm high, and 73 mm deep. Relative humidity minimum is 10 %. The substance prohibitance date is 10/01/2009, indicating RoHS compliance.
Available to order against RFQ through independent distribution channels. Pricing and lead time confirmed at quote time based on the BOM quantity. The part carries the full Siemens compliance documentation package (RoHS, REACH, CE, UL, IEC) as standard for the SIRIUS series.