The 3RT1276-6AD36 is a Siemens SIRIUS vacuum contactor in the Size S12 frame, designed for high-cycle motor switching where arc extinction needs to be fast and contact erosion minimal. Vacuum interrupters mean the arcing time stays tight at 10 to 15 ms, and the contactor handles up to 750 operations per hour in AC-3 duty (and 750/h in AC-3e as well), so it's suited for frequent start-stop profiles on conveyors, pumps, or compressors. The coil pulls in on 42 to 48 V, with a pick-up threshold of 0.8 × rated value and a drop-out band of 0.9 at 50/60 Hz — that's a standard control voltage range for many panel designs.
Termination and cable prep — what lands on the lugs
The main power circuit accepts stranded cable from 70 mm² up to 240 mm² — that's a heavy lug range, typical for feeders in the 200–400 A class. The coil and auxiliary terminals are screw-type, accepting solid or stranded conductors: 2× (0.5 to 1.5 mm²), 2× (0.75 to 2.5 mm²), or max 2× (0.75 to 4 mm²). The auxiliary switch is included (yes, it ships with it), so the kit is complete for feedback or interlock wiring. Fastening is screw fixing through a single 11 mm hole — no DIN-rail clip on this frame; it bolts directly to the panel backplate.
Switching times and coil data — for the commissioning engineer
The full-scale value is 1.1.