What this part does and where it fits
The Siemens 3RV2922-1CB0 is a SIRIUS undervoltage release designed specifically for the 3RV2 family of motor circuit breakers. It drops the breaker's trip mechanism when the control voltage falls below its dropout threshold, preventing an automatic restart after a supply interruption — a standard requirement for machine safety circuits per EN 60204-1. The release is rated for a 24 V AC control supply at 50/60 Hz and carries 2 NO leading auxiliary contacts that change state ahead of the main contacts, giving the control system a status signal before the motor circuit opens. Snap-on mounting onto a 35 mm DIN rail per EN 50022 is the fastening method, and the release occupies an 18.5 mm width — one standard modular unit — so it adds minimal panel footprint alongside the breaker it serves.
Compatibility and ratings
This undervoltage release fits circuit breaker sizes S00, S0, S2, and S3 within the 3RV2 series, covering the common motor-protection range from 0.1 A up to roughly 100 A depending on the breaker frame. The insulation voltage is rated at 690 V AC with pollution degree 3, which is the standard industrial environment classification (conductive pollution or dry non-conductive pollution that becomes conductive due to condensation). That rating means the release is suitable for uncoated use in most control panels without derating for creepage or clearance. The operating temperature range is -20 to +60 °C, and storage range extends from -50 to +80 °C. The 2 NO leading auxiliary contacts are wired via screw terminals, and the release carries the reference code F per EN 61346-2, which designates a protective device function.