What it is and what it does
The Siemens 3RH1122-1KM40-0LA4 is a SIRIUS auxiliary contactor in size S00, designed to switch control circuits — signalling, interlocking, and logic-level loads — in motor starter assemblies and panel builds. It carries 4 normally-open and 2 normally-closed instantaneous contacts, plus a built-in varistor surge suppressor across the coil. Rated 10 A in AC-12 duty (resistive loads at up to 690 V), it handles the control-circuit currents typical of PLC outputs, relay coils, and indicator lamps. The 24 VDC coil draws 11 W on pickup and holds at 4 W.
Mounting and panel fit
Mounts by screw or snaps onto a DIN rail — the 45 mm width and 57.5 mm height fit the standard S00 footprint. Depth is 72 mm, which matters for shallow enclosures where a deeper contactor would crowd the door or busbar. The mounting position is flexible: ±180° rotation on a vertical surface, and can tilt forward or backward by ±22.5°. That helps when panel layout forces an odd angle. Wire terminals accept 2x (0.5 to 1.5 mm²), 2x (0.75 to 2.5 mm²), or 2x 4 mm² solid — covers most control-circuit conductors without needing ferrules.
Environmental and lifecycle
Rated for operation from -40 to +70 °C, storage and transport from -55 to +80 °C. Pollution degree 3 means it's suited for industrial environments with conductive dust or condensation. Shock resistance is 10g at 5 ms and 5g at 10 ms — enough for most machine-mounted panels but not for extreme vibration near presses or crushers.
Sourcing and availability
This is a standard SIRIUS auxiliary contactor — a fast mover in panel-building and MRO. It's sourced and quoted to order against an RFQ through independent distribution, with current pricing and availability confirmed at quote time.