Reversing starter with 53 kA interrupting capacity
The Siemens 3RA6250-2CP32 is a SIRIUS compact reversing starter — a single device that handles forward/reverse motor control and overload protection in one DIN-rail footprint. It breaks 53 kA at 400 V, which means it can interrupt a bolted fault on a high-capacity distribution board without the upstream breaker needing to clear it. That rating covers most industrial panel secondary-fault scenarios up to the transformer. The trip class is adjustable between CLASS 10 and CLASS 20. Set it to 10 for fast-starting loads like pumps and compressors where the motor reaches speed in under 10 seconds; switch to 20 for high-inertia loads like fans or centrifuges that take longer to accelerate. The wrong trip class causes nuisance trips or fails to protect the motor — this part lets you dial it in without swapping the overload block.
Termination and panel fit
Main power connections use spring-loaded terminals — no screw torque to verify, no loosening under thermal cycling. Mounting is screw-and-snap-on to standard DIN rail, with dimensions 191 mm high, 90 mm wide, 165 mm deep. That 90 mm width is three standard 18 mm module slots — plan the gland plate and wireway clearance accordingly. Operating temperature range is -20 to +60 °C, storage and transport from -55 to +80 °C. Pollution degree 3 means it's rated for conductive pollution environments typical of industrial control panels — no conformal coating required for normal factory air.