The Siemens 3RV2902-2AP0 is a SIRIUS undervoltage release designed for use with 3RV2 motor circuit breakers in sizes S00, S0, S2, and S3. It drops the breaker's main contacts when the control supply voltage falls below its dropout threshold, providing undervoltage protection for motor loads. The release is powered by an AC control supply at 230 V / 50 Hz or 240 V / 60 Hz, with a frequency range of 50 to 60 Hz.
Snap-on mounting onto a DIN rail. At 19 mm wide and 68 mm deep, it occupies a single module width on the rail.
Environmental and insulation ratings
The break time is a maximum of 20 ms — fast enough to clear a fault before downstream damage, but check coordination with upstream protective devices.