SIRIUS compact starter for motor protection and control
The Siemens 3RA6120-0DB30 is a SIRIUS compact starter in a direct starter design, rated for continuous operation per IEC 60947-6-2. It combines a contactor and overload relay in a single 45 mm wide housing that mounts on standard DIN rail via screw or snap-on fastening. Rated for motor loads up to 5.5 kW at 400 V, with a breaking capacity of 53 kA at 400 V. The adjustable trip class (CLASS 10 and 20) lets you match the protection curve to the start-up profile of the driven load — pump, fan, or conveyor. Control voltage is 24 V DC, drawing 2.8 W AC maximum and 2.9 W DC maximum. The unit includes two status LEDs and supports any mounting position, though vertical orientation on horizontal DIN rail is recommended.
Integration into the panel — DIN space and wiring
At 45 mm wide, 170 mm tall, and 165 mm deep, the 3RA6120-0DB30 fits a standard 45 mm DIN-rail slot. The main circuit connects via a plug-in interface without terminals (order the matching terminal block separately), which speeds replacement during a line-down event. The compact starter is rated for pollution degree 3, vibration resistance per the listed profile (4–5.8 Hz, 15 mm amplitude; 5.8–500 Hz, 20 m/s²), and shock resistance of 60 m/s² (6g) for 10 ms pulses.
This part is specified into new panel designs and stocked as a line-down spare.