The Siemens 3RT1024-1BP44 is a SIRIUS power contactor in the S0 frame size, designed for switching motor loads up to 7.5 kW at 400 V AC-3. It mounts on a 35 mm DIN rail per EN 50022 via screw or snap-on, fitting standard panel layouts. The front face carries an IP20 rating; the terminal area is IP00, so live parts at the connection point are exposed — keep the panel door closed or use a finger-safe cover. The AC-4 rating at 400 V is 12.5 A — that's the plugging / inching duty cycle, significantly lower than the AC-3 motor-start value, so if your application reverses or jogs the load frequently, size against the AC-4 number, not the 7.5 kW headline.
Coil and control circuit
The DC coil draws 5.4 W both on close and hold — no inrush spike to sag a 24 VDC supply, but the steady-state draw is continuous. Rated control voltage is 230 V. Auxiliary contact ratings: 10 A at 24 V, 6 A at 230 V, 3 A at 400 V, 2 A at 60 V, 1 A at 110 V, 0.3 A at 220 V — use the 230 V / 6 A figure for typical pilot-duty circuits.
Short-circuit coordination
For Type 2 coordination (no damage to the contactor after a fault) the upstream fuse must be gL/gG 25 A. For Type 1 coordination (contactor may need replacement) the fuse can be 63 A. If the panel spec calls for Type 2, the 25 A limit is hard — don't oversize the fuse to save on spares.
Environmental and mounting
Operating temperature range is -25 °C to +60 °C, which covers most indoor panel environments but not a hot roof-top enclosure in direct sun without derating. Altitude limit is 2 000 m; above that, dielectric and thermal margins shrink. Pollution degree 3 — suitable for industrial atmospheres with conductive dust or occasional condensation. Side-by-side mounting is permitted with a 6 mm gap at the side. Dimensions: 85 mm high, 45 mm wide, 150 mm deep.