Reversing starter with 53 kA SCCR — what that means for panel coordination
The 3RA6250-1BB34 is a SIRIUS compact reversing starter rated for 53 kA short-circuit breaking capacity at 400 V. That figure governs selectivity with the upstream protective device — a 53 kA SCCR at the motor branch means the starter clears a fault without forcing the feeder breaker to trip, keeping the rest of the panel online. It carries an adjustable Trip Class of 10 and 20, so the same unit handles both fast-protection (Class 10) for submersible pumps or compressors and slower coordination (Class 20) for high-inertia loads like fans or centrifuges — set it at commissioning, no hardware swap.
DIN rail footprint and wire terminations
The reversing starter measures 90 mm wide by 170 mm high by 165 mm deep — that's a three-wide module on standard 35 mm DIN rail. Mounting is screw-and-snap-on to the DIN rail; the unit can be oriented vertically or horizontally, and the enclosure is rated for pollution degree 3 — standard for industrial control panels with conductive dust or humidity.
Control voltage and environmental limits
Three onboard LEDs give status indication without a separate display. Operating temperature range is -20 to +60 °C; storage and transport range is -55 to +80 °C. Vibration resistance is specified at 20 m/s² from 5.8 to 500 Hz, and shock resistance at 60 m/s² (6 g) for 10 ms — suitable for machine-mounted applications with moderate mechanical stress.