The Siemens 3RV1901-2A is a lateral auxiliary switch from the SIRIUS family, designed to snap onto the side of 3RV2 circuit breakers in sizes S00, S0, S2, or S3. It provides one normally-open and one normally-closed instantaneous contact (1 NO + 1 NC) for signaling the breaker's tripped or on/off state back to a PLC or control circuit. Termination is via spring-loaded terminals (cage clamp), accepting 2x (0.5... 2.5 mm²) solid or 2x (0.5... 1.5 mm²) stranded with ferrules. This avoids screw-torque checks during panel build — strip to 8 mm and push in.
Lifecycle — phased out, successor active
The 3RV1901-2A is a phased-out product. The official Siemens successor is the 3RV2901-2A, a direct drop-in replacement with the same footprint, contact arrangement, and terminal style. For a BOM freeze or a line-down replacement, the 3RV1901-2A is still sourced through independent distribution against an RFQ. Availability and current pricing are confirmed at quote time — the successor 3RV2901-2A is the standard production part and carries no supply risk.
Ratings and what they mean for fit
Contact ratings are given per switching voltage, not a single blanket figure. The maximum thermal current is 10 A, but the make/break capacity at AC-15 drops with voltage: 4 A at 230 V, 3 A at 400 V, and 1 A at 690 V. For DC control circuits, it's 2 A at 24 V and 0.25 A at 220 V. These are the limits for pilot-duty signaling — do not derate from the 10 A maximum without checking the voltage-specific row. Operating temperature range is -20 to +60 °C; storage range is -50 to +80 °C. The part mounts via plug-in fixing — it clips onto the side of the breaker without tools. No DIN-rail space consumed.
Sourcing and RFQ posture
The 3RV1901-2A is not a current-production item. For new designs, specify the 3RV2901-2A. For installed-base support or a last-time-buy, we source the 3RV1901-2A through independent channels against an RFQ. Submit a quote request with your target quantity and timeline; availability and pricing are confirmed at that point.