The Siemens 3RT1517-8BB48-0KT8 is a 4-pole contactor in the SIRIUS S00 frame, rated for AC-3 motor switching at 5.5 kW on a 400 V three-phase line and for AC-1 resistive loads up to 22 A. The DC 24 V coil keeps the control circuit isolated from the power side — standard for PLC-driven panels where a 24 VDC supply is already on the DIN rail. The 4-pole configuration (2 normally open + 2 normally closed main contacts) suits applications like reversing motor starters or dual-load switching where one contactor handles both directions or two independent circuits. The built-in front-side auxiliary switch block adds 3 normally open and 1 normally closed contacts, which eliminates the need for a separate add-on aux block in many panel layouts.
Cage-clamp terminals accept 0.5–2.5 mm² solid or ferruled stranded wire; strip length is 8–10 mm. The DC 24 V coil draws approximately 0.2 A at pickup and holds at about 0.1 A, so a standard 24 VDC power supply with 1 A output can drive several contactors in parallel. Coil suppression is built in; no external free-wheel diode is required for standard PLC outputs.