The Siemens SIRIUS 3RV1901-1F is a transverse auxiliary switch designed to mount on the front of SIRIUS circuit breakers in sizes S00, S0, S2, and S3. It provides two normally open (NO) instantaneous contacts via screw-type terminals, intended for signaling or control interlocking within the breaker's footprint.
Switching capacity and contact ratings
The auxiliary contacts are rated for 1 A at 24 V, 0.3 A at 48 V, 0.15 A at 60 V, and 0.5 A at 230 V. The maximum operational current under AC-12 duty is 2.5 A. These ratings define the load the switch can reliably break — at 24 V it handles a full amp, but at 60 V the current limit drops to 0.15 A, typical for DC switching where arc extinction is more demanding. For a 24 VDC pilot circuit, the 1 A rating gives enough headroom for a small contactor coil or indicator lamp.
Physical integration and wiring
The switch measures 45 mm wide by 17 mm deep by 12 mm high, and fastens via plug-in fixing directly onto the front of the breaker — no DIN rail required. The screw-type terminals accept solid or stranded conductors from 0.5 to 2.5 mm², or two conductors per clamp (2x 0.5…1.5 mm² or 2x 0.75…2.5 mm²). For AWG, the terminals accept 18 to 14 AWG. This is a standard panel-building interface; strip length and torque per the breaker's terminal spec apply.
The manufacturer lists this part as a phased-out product. The preferred successor is the 3RV2901-1F, which performs the same function — transverse auxiliary switch, 2 NO, screw terminals — for the same breaker sizes.
The substance prohibition date of 07/01/2006 aligns with RoHS compliance requirements.