Panel fit and motor protection for a 4 A load
The 3RA6400-1CB42 is a SIRIUS compact starter — a direct-starter design rated 4 A at 400 V AC in continuous duty per IEC 60947-6-2. That 4 A continuous rating sets the motor FLA it can handle; for a 0.75 hp motor at 200/208 V or 220/230 V, or a 2 hp motor at 460/480 V, this is the right-sized spec for the branch. For panels with high available fault current downstream of a large transformer, this starter holds the line without needing a current-limiting upstream device. Trip class is adjustable between CLASS 10 and CLASS 20. CLASS 10 clears a locked-rotor condition in under 10 seconds at 7.2× FLA — the faster trip protects motors with short thermal time constants (conveyor drives, pumps). CLASS 20 gives a longer window for high-inertia loads like fans or centrifuges that take longer to accelerate.
IO-Link integration and wiring constraints
IO-Link COM2 (38.4 kBaud) is onboard — the starter communicates motor current, trip status, and parameter settings back to the controller without extra analog wiring. Three LEDs on the front give local status: power, communication, and fault indication at a glance. That dual-conductor capability is useful when daisy-chaining the supply through the starter to a downstream device — saves a terminal block. Coil is 24 V DC, drawing 2.9 W at rated voltage. The DC coil means no hum and no AC pick-up dropout issues on long cable runs — but the 24 V supply must be sized for the inrush, which is higher than the holding power.
Mounting and environmental tolerance
45 mm wide, 170 mm tall, 165 mm deep — fits a standard DIN rail footprint. Mounting is screw-and-snap-on; the starter can be mounted in any position, though vertical on horizontal DIN rail is recommended for natural convection cooling. Operating temperature range is -20 to +60 °C, storage and transport from -55 to +80 °C. That covers most indoor panel environments and unheated warehouses. Shock resistance is 60 m/s² (6g) for 10 ms, three shocks per axis; vibration tolerance is 15 mm displacement at 4-5.8 Hz and 20 m/s² acceleration at 5.8-500 Hz — rugged enough for machine-mounted panels near conveyor lines or presses. Pollution degree 3 means it's rated for conductive pollution environments — typical in industrial panels where dust, humidity, or occasional condensation are present. No conformal coating required for normal industrial use.