The Siemens SIRIUS 3RV1922-1CV0 is an undervoltage release designed for use with motor circuit breakers in the S00, S0, S2, and S3 size range. It drops the breaker when control voltage falls below the dropout threshold, providing undervoltage protection for motor loads in a panel. The release includes 2 normally-open leading auxiliary contacts that signal the breaker state ahead of the main contacts — useful for sequencing in a safety circuit or PLC input. The 18.5 mm width means it takes up one standard modular slot, leaving room alongside the breaker it serves. IP20 finger-safe front protection is standard, with pollution degree 3 rated insulation at 690 V.
Integration Note
The release snaps onto the left side of the SIRIUS 3RV2 motor circuit breaker. The 2 NO leading auxiliary contacts wire back to the control circuit — typically to a PLC digital input or a safety relay that monitors the breaker's undervoltage state. The 400 V AC coil connects to the line-side control transformer; verify the dropout voltage is below the minimum operating threshold for your control supply. Depth is 68 mm, which is within the standard 70 mm DIN-rail enclosure depth. The 18.5 mm width keeps the assembly compact — a breaker plus this release occupies roughly 63 mm on the rail for an S00 frame, leaving room for auxiliary contact blocks or a shunt trip in the same row.