The Siemens SIRIUS 3RA2315-8XB30-1BB4 is a factory-assembled reversing contactor assembly, size S00, built from two 3RT2015-1BB42 contactors with a mechanical interlock. It's meant for one thing: switching a three-phase motor forward and reverse from a single DIN-rail footprint, no field assembly of interlocks required.
Rated 3 kW at 400 V AC-3, which is the standard duty for squirrel-cage induction motors — that's the figure you match to the motor nameplate. At 480 V it's rated 4.8 A, at 600 V it's 6.1 A, so it tracks the current down as voltage goes up. AC-3 switching frequency maxes at 750 operations per hour, and the mechanical life of the contactor is 10 million cycles. That's a lot of reversals before the contacts wear out — useful on a conveyor sort station or a traverse drive that cycles all shift. That helps when you're shoehorning it into a crowded panel and the DIN rail isn't perfectly level.
Dimensions are 90 mm wide, 68 mm high, 73 mm deep — that's a compact S00 footprint. Clearance around the unit: 6 mm upwards, forwards, downwards, and to the side; zero clearance needed backwards (against the mounting surface). That means you can butt it against the back panel or another rail without leaving an air gap. Terminal capacity on the main circuit: solid or stranded wire 2x (0.5 to 1.5 mm²), 2x (0.75 to 2.5 mm²), or 2x 4 mm². That covers most motor leads in this size class — no need to pigtail down to a smaller wire just to land it.
Shock and vibe
Rated for 10.5 g at 5 ms and 6.6 g at 10 ms on both AC and DC. That's a solid spec for industrial environments — think compressors, crushers, or anything with a hard start that shakes the panel.