The Siemens 3RA2326-8XB30-2FB4 is a SIRIUS reversing contactor assembly — two mechanically interlocked contactors in one package, sized S0, ready to reverse a three-phase motor on command. It ships with two 3RT2026-2FB40 contactors already mounted and interlocked, so you don't have to source the pair separately or build the mechanical interlock yourself. Rated 11 kW at 400 V AC-3 (21 A at 480 V, 22 A at 600 V), it handles reversing duty on pumps, conveyors, and hoists up to that motor load. The 24 V DC coil with a diode-combination surge suppressor means the control circuit is protected against inductive kickback — no external flyback diode needed.
Dimensions are 114 mm high, 90 mm wide, 145 mm deep — fits a standard S0 contactor footprint in the panel. Clearance around the assembly: 6 mm upwards, forwards, downwards, and to the side; 0 mm backwards (mounts flat to the rail). Main current circuit uses spring-loaded terminals; the magnet coil terminates on spring-type terminals as well — no screwdriver needed for wiring. Solid wire accepted: 2x (1 … 10 mm²) for the main circuit, 2x (0.5 … 2.5 mm²) for the control circuit; AWG 18 to 8 for the main contacts.
The AC-3 rating at 400 V (11 kW) is the motor-switching duty figure that governs real use — it's the current the contactor can make and break under full-load motor starting, not just carry continuously. At AC-4 (reversing/inching duty at 400 V) it's rated 7.5 kW — lower because the contactor sees more frequent make/break cycles under load. HP ratings are also listed: 7.5 hp at 220/230 V, 15 hp at 460/480 V, 20 hp at 575/600 V — useful for North American panel builds. Two instantaneous auxiliary contacts are built in for feedback or status signaling. Vibration resistance: 13.5 g / 5 ms and 8.3 g / 10 ms on AC; 15 g / 5 ms and 10 g / 10 ms on DC — tough enough for machine-mounted applications.