The Siemens 3RV2922-1CV1 is a SIRIUS undervoltage release designed for use with 3RV2 motor circuit breakers. It drops the breaker's trip mechanism when the control supply voltage falls below its dropout threshold, preventing an automatic restart after a power loss — a standard requirement for many machine safety circuits and process interlocks. It accepts a 415 V AC control supply at 50 Hz and 480 V AC at 60 Hz, covering the common line-to-line voltages across 50 Hz and 60 Hz industrial networks. The release operates within a 50...60 Hz frequency range, so it tracks the line frequency without adjustment.
Auxiliary contacts and wiring
The release carries 2 normally-open leading auxiliary contacts. These are wired into the control circuit to signal the release's state — closed when the undervoltage coil is energized, open when it drops out. The leading-contact design means the auxiliary contacts change state slightly ahead of the main contacts, useful for sequencing or status feedback. Connections are via screw-type terminals, a conventional choice that accepts solid or stranded wire without special tooling. The 19 mm width matches the standard 3RV2 breaker module pitch, so it snaps onto the same DIN rail footprint without stealing extra panel space.
The 68 mm depth and 90 mm height are identical to the base breaker, so the assembly sits flush in the enclosure.