The Siemens 3RH2131-1BA40 is a SIRIUS auxiliary contactor in frame size S00, carrying 3 normally-open and 1 normally-closed instantaneous contacts. It is designed for control-circuit switching — signaling, interlocking, and logic-level isolation inside a motor control center or panel — not for direct motor loads. The coil pulls in at 24 VDC nominal, consuming 4 W during both pick-up and hold, so there is no inrush spike to size a power supply around. Rated switching capacity at 24 V is 10 A; at 230 V AC it also carries 10 A, dropping to 3 A at 400 V and 1 A at 690 V — the AC-15 / DC-13 curves govern the actual contact life under inductive loads. The maximum switching rate on AC is 10,000 operations per hour; on DC the arcing time sits between 7 and 15 ms.
The S00 footprint is 45 mm wide, 57.5 mm tall, and 73 mm deep. Wire terminals accept 2 x 0.5 to 1.5 mm² solid or stranded, 2 x 0.75 to 2.5 mm², or 2 x 4 mm² — spring-cage or screw terminals depending on the variant.
Relative humidity minimum is 10 %. RoHS compliance substance prohibition date is October 1, 2009, which aligns with the EU RoHS directive timeline.