The Siemens 3RT1034-1QB44-3MA0 is a SIRIUS power contactor in the S2 frame size — the workhorse for switching three-phase motor loads up to 18.5 kW at 500 V under AC-3 duty. The 24 VDC coil pulls in reliably and holds at 0.8 of rated, so it's suited for PLC-driven 24 V control circuits common in automated lines.
The 55 mm width and 112 mm height are standard for the S2 frame — it'll fit alongside overload relays and busbars in a compact motor control center. Wiring is via screw terminals on the main circuit, accepting solid conductors up to 2x (0.75...4 mm²) and stranded up to 2x (0.75...25 mm²). The terminal rating is IP00 at the connection point, while the front face carries IP20 — finger-safe once installed in an enclosure, but the wiring side needs the panel cover closed before anyone reaches in.
Duty cycles and environment
Operating temperature spans -25 to +60 °C, with storage from -55 to +80 °C — fine for most indoor industrial panels, though if you're mounting it near a furnace or in a desert plant, keep the ambient under 60. Mechanical life is typical at 10 million operations; electrical life varies by duty: 1,200 cycles/hour at AC-1, 1,000 at AC-3, and 250 at AC-4 — the AC-4 figure is the one to watch if you're doing frequent reversing or plugging.