SIRIUS contactor, size S00 — 24 V DC coil, 5.5 kW AC-3
The Siemens 3RT2317-2BB40 is a SIRIUS contactor in the compact S00 frame, rated for 5.5 kW motor switching at 400 V in AC-3 duty — the standard induction-motor load class. The 24 V DC coil pulls in reliably and holds without hum, making it a common choice for PLC-driven panels where a 24 VDC control bus is already present. Spring-loaded terminals on both the main circuit and the coil eliminate the need for screwdriver torque checks during panel build — strip 8–10 mm, push in, done. The contactor snaps onto 35 mm DIN rail per DIN EN 60715 and can be mounted in any orientation, including rotated ±180° on a vertical surface or tilted ±22.5° forward/backward, which simplifies fitting into crowded enclosures.
The AC-3 rating of 5.5 kW at 400 V is the figure that governs motor switching — it covers a standard 7.5 hp (5.5 kW) four-pole induction motor in a pump, fan, or conveyor application. The AC-4 rating of 4 kW at 400 V applies when the contactor must make and break the motor under inching or plugging duty, where the current is higher and the arc is more severe. Mechanical endurance of 30 million operating cycles is typical for the S00 frame; the contactor is built for high-cycle applications like packaging machines or material-handling sorters where the contactor cycles every few seconds.
Mounting and wiring — panel integration
That side clearance is the tightest dimension; if you stack contactors flush, the 6 mm gap must be maintained for heat dissipation. Terminals accept solid conductors 2x (0.5 to 2.5 mm²) or stranded 0.5 to 4 mm². The spring-loaded design on the main circuit means no screw tightening — just strip and insert. For the coil, the same spring-cage style applies.