The Siemens 3RT1044-1AP60 is a SIRIUS S3 power contactor built for motor switching in control panels. It carries a 37 kW rating at 500 V AC-3 and 18.6 kW at 690 V AC-3, which covers the common 400 V and 690 V industrial motor loads in Europe and export machinery. Mounting is screw-and-snap-on onto 35 mm or 75 mm standard DIN rail, and side-by-side mounting is permitted — no derating gap required between units in a multi-contactor group. The IP20 front with cover or box terminal keeps live parts behind the panel door, while the terminal block itself is IP00, which is normal for this class.
Sizing and duty-cycle fit
For a packaging line running 20 cycles per minute, the AC-3 rate gives headroom; for a reversing conveyor section with frequent plugging, the AC-4 rate governs the selection. The terminal wiring capacities are identical across these S3 variants — solid 2x (0.5–1.5 mm²) and stranded 2x (10–50 mm²) — so the control wiring plan stays unchanged.
Environmental and installation limits
Coil operating range is 0.8–1.1 x rated voltage at both 50 Hz and 60 Hz, with an arcing time of 10–15 ms and closing time of 10–19 ms. These timing figures matter for coordination with upstream short-circuit protection devices — the contactor clears its arc before a fast-acting fuse element reaches its melting point.