The Siemens 3RT1617-1AK63 is a SIRIUS capacitor contactor rated for AC-6 duty at 12.5 kVAr at 400 V, meaning it is designed specifically for switching capacitor banks in power-factor correction panels — the AC-6 rating accounts for the high inrush current typical of capacitive loads, which a standard AC-3 motor contactor cannot handle without contact welding. Main contacts are 3 NO rated at 20 A; the auxiliary contact block carries 1 NC and 1 NO, identified as switching element 11.
Dimensions are 45 mm wide by 110 mm deep by 110 mm tall, so it occupies a standard 45 mm module width on the rail. Both main and auxiliary circuits use screw-type terminals, so no special tooling is needed for field wiring.
This part is marked as a phased-out product — the official Siemens successor is the SIRIUS 3RT2 series, specifically order code 3RT2617-1AK63. For a BOM line that still calls out 3RT1617-1AK63, the replacement is a form-fit-function drop-in: same 45 mm width, same AC coil voltage, same AC-6 kVAr rating, and same auxiliary contact configuration. The 3RT2 series uses the same DIN-rail footprint and terminal layout, so no panel rework is required.
Environmental and protection class
IP20 rated on the front and at the terminals, so it is suitable for installation inside a locked enclosure where personnel cannot contact live parts — standard for panel-mounted contactors.