The Siemens 3RA6400-1CB43 is a SIRIUS compact starter designed as a direct starter for IO-Link communication. The unit is rated for continuous operation per IEC 60947-6-2. Rated at 4 A at 400 V AC (AC-3 motor duty), it handles motors up to 1.5 kW at 400 V and 2 hp at 460/480 V. The control supply is 24 V DC, drawing a maximum power dissipation of 2.9 W. The coil holds in at 24 V nominal; the dropout threshold is not listed here but is typically below 18 V for this class. The part carries three LEDs for status indication, and the IO-Link interface runs at COM2 (38.4 kBaud), enabling parameter setting and diagnostics from a PLC or IO-Link master.
Trip class and protection flexibility
The overload relay section offers adjustable trip class 10 and 20. Class 10 is the standard for standard-start induction motors; Class 20 allows longer acceleration time for high-inertia loads like fans or centrifuges.
No official replacement has been announced; the 3RA6400-1CB43 is the current generation of SIRIUS compact starter for IO-Link.
Integration and environmental limits
The 45 mm width means it occupies one standard module position. Shock resistance is 60 m/s² (6 g) for 10 ms, three shocks per axis; vibration resistance covers 4 to 5.8 Hz at 15 mm amplitude and 5.8 to 500 Hz at 20 m/s² for 10 cycles.