What this part is and what it does
The Siemens 3RV1922-1CP0 is a SIRIUS undervoltage release designed for use with motor circuit breakers in sizes S00, S0, S2, and S3. Its job is to trip the breaker when the control supply voltage drops below the dropout threshold, preventing an unexpected restart when power returns — a standard requirement for machine safety circuits per IEC 60204-1. The coil is rated for 230 V AC at 50 Hz and 240 V AC at 60 Hz, so it's suited for 230/240 V line-to-neutral control circuits common across European and North American panels.
Key ratings and what they mean for fit
The release carries 2 NO (normally open) leading auxiliary contacts — these close when the release is energized and open on undervoltage, providing a positive status signal to the PLC or safety relay. The leading-contact design means the auxiliary contacts change state slightly ahead of the main contacts, which is useful for signaling readiness before the breaker closes. Snap-on mounting onto a 35 mm DIN rail per EN 50022 keeps installation straightforward; the 18.5 mm width means it occupies a single 18 mm modular slot, and the 68 mm depth fits standard enclosure depths without crowding the gland plate. IP20 finger-safe protection on the front (per IEC 60529) allows vertical contact from the front without risk of shock, which is the minimum for a panel-mounted control device.
Lifecycle and sourcing reality
The 3RV1922-1CP0 is a phased-out product. The official Siemens successor is the 3RV2922-1CP0, which is the preferred replacement type. For a BOM line that still specifies this order code, the part is sourced through independent distribution channels and quoted to order against an RFQ — availability and current pricing are confirmed at quote time. If you're planning a new panel build, the successor is the cleaner path; for a line-down replacement on an existing panel, this part remains available through the surplus and broker channel.