What it is and what it does
The Siemens SIRIUS 3RV1902-1AN6 is an undervoltage release — a control accessory that trips a circuit breaker when supply voltage drops below a set threshold, protecting motors and downstream equipment from running under brownout conditions. It's designed for 200 V control circuits and mounts directly onto SIRIUS 3RV motor-protective circuit breakers in the S00 frame size.
Integration note
Snap-on mounting onto a 35 mm DIN rail per DIN EN 60715, same footprint as the SIRIUS 3RV1 breaker family. Screw-type terminals accept 2x (0.5…1.5 mm²) solid or 2x (0.75…2.5 mm²) finely stranded with ferrule. Torque to 0.8…1.2 N·m. The release shares the breaker's auxiliary contact slot — verify free-wheel diode polarity if the control circuit includes an inductive load.