Siemens SIRIUS 3RT1317-1FF40 power contactor — size S00, 110 V DC coil
The Siemens SIRIUS 3RT1317-1FF40 is a size S00 power contactor with a 110 V DC coil, designed for switching motor loads and resistive loads in industrial control panels. It carries 4 normally-open main contacts and zero normally-closed main contacts, so it is configured for make-only duty — suitable for applications where the load is disconnected by a separate upstream device or where the contactor simply closes to energize a circuit. Rated for AC-2 duty at 400 V up to 5.5 kW, this contactor handles slip-ring motor starting and reversing, where the contacts make and break under load at reduced current. The DC coil draws 3.3 W for both closing and holding, so the control transformer or power supply must be sized for that inrush — no coil economy circuit is built in, but the integrated diode surge suppressor protects the DC control loop from flyback voltage when the coil de-energizes. Mounting is via screw and snap-on onto 35 mm DIN rail per EN 50022. The 45 mm width matches the S00 frame footprint, leaving room for auxiliary contact blocks side-by-side. IP20 on the front and at the terminals means the contactor is protected against finger contact but is not sealed — install inside an enclosure rated for the environment.
Integration — panel fit and wiring
The screw-type terminals on the main circuit accept 2x (0.5 to 1.5 mm²), 2x (0.75 to 2.5 mm²), or up to 2x (0.75 to 4 mm²) solid or stranded conductors. AWG equivalents are 2x (20 to 16), 2x (18 to 14), and 1x 12. The 72 mm depth leaves clearance for wiring ducts and adjacent components on the DIN rail. Side-by-side mounting is permitted without derating, so multiple contactors can be ganged on the same rail for multi-motor groups. The 6 mm spacing at the side is the minimum air gap to adjacent live parts — maintain that for creepage and clearance at pollution degree 3. For type 2 coordination (no damage to the contactor under short circuit), the required upstream fuse is gL/gG 20 A. For type 1 coordination (contactor may need replacement after fault), the fuse can be 35 A. This matters when coordinating with motor branch circuit protection — match the fuse class and rating to the coordination type your panel design specifies.
Operating conditions and ratings
Operating temperature range is -25 to +60 °C, covering most indoor industrial environments. Maximum operating altitude is 2 000 m without derating. The coil pick-up voltage is 0.85 x rated (93.5 V DC minimum), and the full-scale drop-out is 1.1 x rated (121 V DC), so the contactor holds in during dips but drops out reliably on undervoltage. Auxiliary switching capacity at 24 V DC is 10 A, at 110 V DC is 1 A, and at 220 V DC is 0.3 A — typical for DC load breaking where arc extinction is slower than AC. The mechanical life is 30 million operations, so this contactor is suited for high-cycling applications like conveyor indexing or packaging machines.