The Siemens 3RA2318-8XB30-1AK6 is a SIRIUS reversing contactor assembly — a pre-wired pair of contactors with mechanical interlock that reverses a three-phase motor without external wiring. It ships with two 3RT2018-1AK62 contactors already mounted and interlocked, so the panel builder gets a single order code instead of sourcing contactors, interlock, and bus bars separately. Rated at 7.5 kW at 400 V AC-3 (14 A at 480 V, 10 hp at 460/480 V), it handles reversing duty on pumps, conveyors, and small hoists within that motor current envelope. The S00 frame keeps the footprint tight: 90 mm wide, 68 mm tall, 73 mm deep. Screw-type terminals on both the main circuit and the coil accept 2x (0.5…1.5 mm²), 2x (0.75…2.5 mm²), or 2x 4 mm² solid or stranded conductors — no ferrule crimping needed for the larger sizes.
The 90 mm width and 68 mm height mean it occupies roughly the space of two standard contactors side by side, but pre-interlocked. Shock resistance is rated at 11.4 g for 5 ms and 7.3 g for 10 ms on both AC and DC axes — robust enough for machine-mounted applications with moderate vibration.