Siemens 3RT1034-1BW40-ZX95 — SIRIUS S2 Power Contactor
Rated for AC-3 duty at 400 V at 18.5 kW and AC-4 at 400 V at 29 A, this contactor handles induction motor starting and inching/plugging applications. For DC loads, it switches up to 10 A at 24 V, 2 A at 60 V, and 0.3 A at 220 V — figures that govern its use in battery-backed or DC bus circuits. The enclosure is rated IP20 on the front and IP00 at the terminal area, meaning it requires installation within a higher-rated cabinet for washdown or dusty environments.
For BOM freeze or compliance audits, the part carries a substance prohibitance date of 05/01/2012, aligning with RoHS and REACH requirements.
Installation & Integration Notes
Side-by-side mounting is permitted, which simplifies multi-contactor motor starter assemblies on a single DIN rail segment. The S2 frame leaves clearance for auxiliary contact blocks on either side — verify the ZX95 suffix denotes any special packaging or variant marking, not a functional change.
Why This Rating Set Matters for Your BOM
The AC-3 maximum switching rate of 1,000 operations per hour suits frequent start-stop cycles on conveyors or pumps, but not the high-duty inching of AC-4 (250 ops/h). The 10,000,000 mechanical cycle rating gives a long service life under normal motor switching. DC switching ratings are derated significantly from AC — the 10 A at 24 V drops to 0.3 A at 220 V due to arc extinction limits. If your BOM uses this contactor in a DC circuit above 60 V, confirm the load current is under the 2 A threshold at that voltage.