The Siemens 3RV2902-2DB0 is a SIRIUS shunt release designed for remote tripping of 3RV2 motor circuit breakers in sizes S00, S0, S2, and S3. It accepts a 20-24 V AC control supply at 50/60 Hz and is rated for continuous duty at that voltage, with a separate 5-second ON period rating of 20-70 V AC or DC for applications needing a higher momentary pull-in voltage. The shunt release snaps onto the breaker's side via the standard DIN-rail mounting system — no additional panel space required beyond the breaker's own 19 mm width.
The 20-24 V AC control supply is the continuous-duty range — the coil can be energized indefinitely at that voltage. The 5-second ON period rating of 20-70 V AC or DC is a separate, higher-voltage capability for applications where the trip signal is a short pulse, not a sustained hold. This dual rating is unusual for a shunt release and gives flexibility in control schemes: use the continuous range for standard undervoltage release circuits, or the short-pulse range for PLC-driven trip commands that clear after the breaker opens. The 20 ms break time is the mechanical opening delay once the coil is energized — fast enough for most motor protection coordination schemes.