What it is and where it fits
The Siemens 3RV1902-1AM1 is a SIRIUS undervoltage release for motor circuit breakers in sizes S00, S0, S2, and S3. It snaps onto a DIN rail and provides undervoltage protection for the breaker's control circuit, tripping the breaker when the supply voltage drops below the release threshold. Rated at 208 V AC, 60 Hz, it operates across a -20 to +60 °C ambient range and is rated for IP20 finger-safe touch protection on the front.
Panel integration notes
Snap-on mounting onto a DIN rail. The 18.5 mm width and 68 mm depth leave room for adjacent devices in a crowded enclosure — no special spacing needed for this release alone. Insulation voltage rated at 690 V with pollution degree 3, so it's suited for industrial panels where conductive dust or humidity is present.