Reversing starter with 53 kA SCCR at 400 V
The Siemens 3RA6250-2AB32 is a SIRIUS compact reversing starter — a single device that handles forward/reverse motor control in one DIN-rail footprint. It's rated for continuous operation per IEC 60947-6-2, meaning it's built for sustained duty on conveyors, pumps, or fans where direction reversal is part of the cycle. The headline number here is 53 kA at 400 V — that's the rated short-circuit breaking capacity. That's a high interrupting rating for a compact reversing starter, so it can sit downstream of a transformer or a high-capacity bus without requiring a current-limiting fuse ahead of it.
Trip class and control voltage — what they mean for the line
Trip class is adjustable between CLASS 10 and CLASS 20. CLASS 10 trips in under 10 seconds at 7.2× FLA — that's the standard for motor protection on pumps and fans where the start-up is quick. Having both in one starter means you don't swap overload relays when the load changes; you dial it in. This is a standard control voltage in industrial panels, so it drops into an existing 24 VDC control bus or a 24 VAC transformer circuit without a separate power supply. The coil draws 2.8 W AC maximum and 2.9 W DC maximum — low enough that a 24 VDC power supply rated for a few amps can run a bank of these starters. Spring-clamp terminations are faster to wire than screw terminals and hold better under vibration — a real advantage on a reversing starter that sees frequent switching cycles.
Panel fit and environmental tolerance
The 3RA6250-2AB32 measures 90 mm wide, 191 mm high, and 165 mm deep. It mounts on a standard DIN rail via screw and snap-on fastening — the snap-on locks it in place, the screw secures it for high-vibration environments. Mounting position is any, so it fits tight enclosures where you need to orient it sideways or upside-down. That covers most indoor industrial environments and unheated warehouses. Vibration resistance is spec'd at 4 to 5.8 Hz with 15 mm amplitude, and 5.8 to 500 Hz at 20 m/s² for 10 cycles — it's rated for machine-mounted applications like conveyor drives or compressor skids. Shock resistance is 60 m/s² (6g) for 10 ms, three shocks per axis. Degree of pollution 3 means it's rated for conductive pollution environments — typical in factory floors where dust, oil mist, or humidity are present. The three LEDs on the front give visual status indication for the control circuit, which helps during commissioning and fault-finding without needing a multimeter.
No official successor or cross-reference is listed — the 3RA6250-2AB32 is the active version in the SIRIUS compact starter family. If you're replacing an older reversing starter in a panel, the 90 mm width and DIN-rail mount make it a drop-in for most standard layouts, but confirm the control voltage (24 V AC/DC) and the spring-clamp termination style against your existing wiring.