The Siemens SIRIUS 3RV1922-1CB0 is an undervoltage release designed to drop a circuit breaker when supply voltage falls below its holding threshold. The front is finger-safe to IP20 per IEC 60529, meaning accidental contact with live terminals during panel work is protected against — a standard requirement for control cabinets where operators reach in.
Mounts onto the front of a SIRIUS 3RV2 motor starter protector or 3RV2 circuit breaker in frame sizes S0 through S3. The IP20 finger-safe front means no additional cover is needed for the release terminals in a standard IP20 panel. The 2 NO auxiliary switch signals the undervoltage condition back to a PLC or status lamp — useful for a commissioning engineer verifying the drop-out sequence during FAT.