The Siemens 3RA2338-8XB30-1AL2 is a SIRIUS reversing contactor assembly — a pre-wired, mechanically interlocked pair of contactors that reverses a three-phase motor by swapping two phases. It ships with two 3RT2038-1AL20 contactors (one per direction of rotation) already mounted on a common base plate, saving panel-build time over sourcing and interlocking individual contactors. Rated 37 kW at 400 V AC-3 (motor duty) and 65 A at 480 V, it handles reversing loads like conveyors, hoists, and pump sets. The AC-3e rating matches the same 500 operations/hour maximum, meaning the assembly is sized for frequent jogging or inching without exceeding thermal limits. The S2 contactor frame keeps the footprint compact: 120 mm wide, 141 mm tall, 130 mm deep. Clearance requirements are minimal — 10 mm upwards, forwards, downwards, and to the sides, with 0 mm needed backwards — so it fits tight enclosures.
The 37 kW at 400 V AC-3 rating governs motor switching up to that power — typical for a 50 hp class motor on 460/480 V systems (50 hp at 460/480 V is the listed rating). At 575/600 V it carries 60 hp, and at 690 V it reaches 45 kW. The 65 A at 480 V and 62 A at 600 V are the thermal current limits for the main power path. The coil terminals are screw-type, as are the main circuit terminals. The main power wires accept solid conductors from 1 to 50 mm² (single) or 2x 1 to 35 mm² (parallel). Auxiliary control wiring takes 2x 0.5 to 1.5 mm² solid or stranded. The assembly includes 2 instantaneous auxiliary contacts for feedback or interlocking. Shock resistance is 18.5g at 5 ms and 11.6g at 10 ms — suitable for applications with moderate vibration, though not rail or marine without additional dampening.
Where this class of part is used
Reversing contactor assemblies like this one are deployed in motor control centers and standalone panels wherever a three-phase motor must run in both directions — conveyor belts, overhead cranes, gate openers, mixing vessels, and any process that requires forward/reverse cycling. The SIRIUS S2 platform is Siemens' compact reversing solution for the 37 kW class.
The assembly ships with two 3RT2038-1AL20 contactors. If you already stock that contactor individually, the pre-assembled 3RA2338 saves wiring time but uses the same base component.