What this contactor is and where it fits
The Siemens SIRIUS 3RT1017-1BA42 is a Size S00 power contactor rated for motor switching at 5.5 kW in AC-3 duty at 400 V, with a 24 VDC coil drawing 3.3 W for both closing and holding. It mounts via screw or snap-on onto 35 mm DIN rail per EN 50022, making it a direct fit for standard industrial control panels. The 45 mm width and 57.5 mm height keep the footprint compact for dense panel layouts.
Key ratings and what they mean for your application
The AC-3 rating of 5.5 kW at 400 V governs the motor load this contactor can switch under starting conditions — that's the figure to match against your motor nameplate, not the AC-1 resistive rating. For reversing or inching duty (AC-4), the contactor is rated at 8.5 A at 400 V, which is lower than the AC-3 current, so factor that in for jogging or plugging applications. The 24 VDC coil holds at 3.3 W, which is consistent across closing and holding, meaning no inrush spike to size your control transformer around. Mechanical life is rated at 30 million operating cycles, so this contactor is built for high-cycle applications like conveyor lines or pump stations where the contactor sees frequent switching. Operating temperature range of -25 to +60 °C allows installation in unheated enclosures or near process heat, but derate above 40 °C per the thermal curve. The screw terminals accept solid or stranded conductors: 2x 0.5–1.5 mm², 2x 0.75–2.5 mm², or max 2x 0.75–4 mm² per clamp. For AWG, that's 2x 20–16, 2x 18–14, or 1x 12. The IP20 finger-safe protection on the front and terminals means the contactor can be mounted in a panel without additional terminal shrouds for basic touch protection.
Mounting and coordination
Snap-on mounting onto 35 mm DIN rail per DIN EN 50022 is standard; the screw-mount option is also available. Side-by-side mounting is permitted without derating, which simplifies panel layout for multi-contactor groups. For Type 1 coordination, use a gL/gG fuse rated 35 A; for Type 2 coordination, use 20 A. Pollution degree 3 means the contactor is rated for industrial environments with conductive pollution, typical for control panels without climate control.