The Siemens 3RT1317-1BG40 is a SIRIUS power contactor in the compact Size S00 frame, with four normally-open main contacts rated for motor switching at 5.5 kW in AC-2 duty at 400 V. The screw-type terminals accept up to 4 mm² per pole, and the 45 mm width lets it snap onto a 35 mm DIN rail per EN 50022 alongside other S00 devices without extra spacing.
The 5.5 kW AC-2 figure at 400 V is the motor-switching capacity that governs real-world fit — not the AC-1 resistive rating. For a 5.5 kW wound-rotor motor or a reversing conveyor drive, this contactor handles the inrush and break current within its electrical life. The 4 NO main contacts give you four independent power poles, which is useful for two-speed motors or for switching a second load leg without an extra contactor block. Type 1 coordination requires a 35 A gL/gG fuse upstream; Type 2 coordination drops that to 20 A. That difference matters when you're coordinating with a motor starter or a downstream short-circuit device — Type 2 keeps the contactor usable after a fault, Type 1 may weld the contacts.
Side-by-side mounting is allowed with a 6 mm gap to the side for heat dissipation. The screw terminals accept 2x (0.5 to 1.5 mm²), 2x (0.75 to 2.5 mm²), or max 2x (0.75 to 4 mm²) — fine for the main circuit wiring. Depth is 72 mm, height 57.5 mm, so it fits in shallow enclosures.