SIRIUS S00 auxiliary contactor — 2 NO, 24 V DC coil
The 3RH2122-1BB40 is a SIRIUS auxiliary contactor in frame size S00, carrying two normally-open instantaneous contacts and a 24 V DC magnet coil that draws 4 W closing and 4 W holding power. It screws or snaps onto a 35 mm DIN rail — the S00 footprint (45 mm wide, 57.5 mm tall, 73 mm deep) fits standard panel layouts and leaves clearance for side-by-side ganging: 6 mm to the side, 10 mm forward and upward.
Contact ratings and switching capability
The NO contacts are rated 10 A at 24 V DC and 10 A at 230 V AC, with a mechanical life of 30 million operations typical — the electrical endurance depends on the switched load, not the contact itself. At higher DC voltages the current rating drops: 4.7 A at 60 V, 3 A at 110 V, 1.2 A at 220 V, and 0.26 A at 600 V — the arcing time of 10–15 ms sets the DC switching limit, so confirm the load's inductive time constant against the contact's DC-13 capability. AC switching covers the full line range: 10 A at 230 V, 3 A at 400 V, 2 A at 500 V, 1 A at 690 V — the contactor handles up to 10,000 switching cycles per hour at rated load.
Mounting and environmental fit
Mounting position is flexible — the contactor can be rotated ±180° on a vertical surface and tilted forward or backward ±22.5°, which helps when fitting into tight panel sections or angled sub-panels. Operating temperature spans -25 to +60 °C with storage from -55 to +80 °C, and it's rated for pollution degree 3 — suitable for industrial control cabinets where conductive dust or condensation is present. The screw terminals accept 2× 0.5–1.5 mm² solid or stranded, 2× 0.75–2.5 mm², or a single 4 mm² conductor — covers most control wiring gauges found in MRO spares bins.
Sourcing and lifecycle
The 3RH2122-1BB40 carries the SIRIUS brand and is part of Siemens' standard auxiliary contactor range — a widely stocked SKU that consolidates well with other S00-frame contactors and overload relays in the same panel.