The Siemens SIRIUS 3RV1902-1DF0 is a shunt release — a remote-trip accessory for motor circuit protectors. It sits on the front of the breaker and, when its coil is energized, mechanically trips the breaker independent of overload or short-circuit conditions. This one is wound for 110 V AC at 50/60 Hz, with a pickup range of 90-110 V AC for continuous duty, and can also handle 70-190 V AC for a 5-second pulse. The coil holds at 110 V AC nominal. Below 90 V AC it drops out — that's the undervoltage release behavior baked into this design. The 100% ON period rating means you can keep it energized indefinitely in a safety circuit that needs to hold the breaker tripped until manually reset.
The successor 3RV2902-1DF0 is a form-fit-function drop-in for new designs and BOM revisions. For existing panels already carrying the 3RV1902-1DF0 on the BOM, the 3RV2902-1DF0 mounts in the same footprint and connects identically — no wiring changes, no DIN-rail rework.
Snap-on mounting onto the circuit breaker front — no DIN rail required. The release fits Siemens SIRIUS breaker frames S00, S0, S2, and S3. At 18.5 mm wide, 90 mm tall, and 68 mm deep, it adds negligible panel depth beyond the breaker itself. Finger-safe IP20 front protection per IEC 60529 means it can sit in a live panel without additional shrouding. No auxiliary contacts are included — this is a pure trip coil, not a status feedback device.
The 90-110 V AC pickup range at 50/60 Hz means this release works on control transformers supplying 110 V nominal across both common line frequencies. The 70-190 V AC 5-second pulse rating allows it to be used in applications where the control voltage is higher than the continuous coil rating, as long as the pulse duration is limited — useful for momentary trip circuits in remote or battery-backed schemes.