The Siemens 3RA2225-4BD26-0BB4 is a non-fused reversing motor starter from the SIRIUS family, size S0, designed to switch a motor in both directions from a single control signal. It ships as a factory-assembled unit that includes the contactor 3RT2026-1BB40, the link module 3RA2921-1BA00, and the busbar adapter 8US1251-5NT10 — so you get the reversing interlock and the overload protection in one package, not a pile of loose parts to wire up on the bench. The overload release is thermal bimetallic, trip class 10, which means it protects standard induction motors against running overloads and locked-rotor conditions by following the motor's heating curve. Class 10 is the typical choice for general-purpose conveyor, pump, and fan drives — it trips fast enough to protect the motor windings but not so fast that it nuisance-trips on a normal start.
This reversing starter snaps directly onto 60 mm busbar systems — no DIN rail adapter needed, no extra brackets. Mounting position is vertical only, so plan the enclosure layout with that orientation locked in. The depth is 165 mm, width 90 mm, height 260 mm — factor that into your gland-plate and wireway fill before you start pulling cables. Main contact stranded wire range is 1 to 10 mm², or 2x (2.5 to 6 mm²) for paralleled feeds.
The coil is 24 V DC rated value. At AC-3 duty (the standard motor-switching category) the maximum operating voltage is 690 V. Power ratings vary by line voltage: at 400 V it handles 7 500 W (10 hp), at 460/480 V it handles 10 hp, and at 575/600 V it handles 15 hp. Current ratings at 480 V are 15.2 A, at 600 V are 17.8 A. These are the numbers that govern the motor nameplate match — size the overload relay to the motor FLA, not the starter's maximum. Operating temperature range is -20 to +60 °C, storage -50 to +80 °C, transport -55 to +80 °C. The starter is rated for a 3 hp motor at 230 V, 5 hp at 200/208 V and 220/230 V, and 1.5 hp at 110/120 V — useful if you're feeding a motor from a control transformer on a lower-voltage control bus.