48 V coil and 2 N/O contacts — what the switching ratings mean
The 3RH2122-2BW40 is a SIRIUS S00 auxiliary contactor with a 48 V DC coil, carrying 2 instantaneous normally-open contacts. The coil draws 4 W both for closing and holding — no economizer circuit needed, so the thermal load on the DC supply is constant at 4 W. Rated operational current varies significantly with switching voltage: at 24 V it handles 10 A, at 110 V it drops to 3 A, and at 600 V it is rated 0.26 A. These are not derating curves — they reflect the arc extinction capability of the contact gap at different DC voltages. At 10,000 switching cycles per hour AC, the contactor can sustain continuous high-speed operation without exceeding the thermal limits of the coil.
Mounting accepts both screw-fixing and snap-on onto standard 35 mm mounting rail. Pollution degree 3 rating means the contactor is designed for industrial environments where conductive contamination (dust, condensation) may occur — the creepage distances and clearance gaps are sized accordingly.
Lifecycle and compliance — active production, RoHS dated
Production status is active — the 3RH2122-2BW40 is a current catalog item within the SIRIUS contactor family. The auxiliary switch extension is available as a separate order (product extension auxiliary switch: yes). RoHS compliance is documented with a substance prohibition date of 10/01/2009 — the contactor meets the EU RoHS directive as of that date. Minimum relative humidity for storage is 10 %, which covers dry warehouse conditions. No UL or CSA listing is explicitly stated in the available spec data; the design follows IEC/EN standards typical for SIRIUS components.