The Siemens SIRIUS 3RV1922-1CU0 is an undervoltage release designed for circuit breakers in Size S0 through S3. The front is finger-safe to IP20 per IEC 60529, meaning accidental contact from the front is protected against during normal panel access.
The 240 V AC 50 Hz coil voltage is the critical fit parameter — this release drops out the circuit breaker when supply voltage falls below its dropout threshold, protecting motors and loads from undervoltage conditions. It mounts directly onto the front of SIRIUS 3RV1 circuit breakers in Size S0, S1, S2, or S3, snapping into the accessory slot without additional wiring to the main power path. The IP20 finger-safe front means it meets touch protection standards for vertical contact, so it can be placed in a panel with other live parts without requiring a separate cover over this accessory.