The Siemens SIRIUS 3RV1922-1CG6 is an undervoltage release with a leading auxiliary switch rated for 100 V. It is an accessory designed to drop out a motor-protective circuit breaker when the control voltage falls below its dropout threshold, preventing automatic restart on brownout conditions. The leading auxiliary switch signals the undervoltage state ahead of the main contact opening, which is useful for sequencing downstream controls in a panel.
The 100 V operating voltage is the coil rating — this release is intended for control circuits where the undervoltage protection must trigger at a 100 VAC threshold. The leading auxiliary switch provides a dry-contact status output that changes state before the main breaker trips, so a PLC or safety relay can latch a shutdown sequence or annunciate the condition before the motor circuit actually opens. This is common in conveyor interlock schemes where a momentary voltage sag should not cause a full line restart without operator acknowledgment.
Panel integration
No additional wiring space is needed beyond the standard side clearance for the breaker it attaches to. The screw terminals accept 2x (0.5 to 1.5 mm²) solid or stranded, or 2x (0.75 to 2.5 mm²) finely stranded with ferrule. Torque to 0.8–1.2 N·m.