What this SIRIUS compact starter delivers
The Siemens 3RA6120-1EE33 is a SIRIUS compact starter in a direct-starter design, rated for continuous operation per IEC 60947-6-2. The control coil accepts 42-70 V AC/DC. Power dissipation is 3.2 W AC max and 4.2 W DC max. Trip class is adjustable between CLASS 10 and CLASS 20, letting you match the overload curve to the motor start profile — CLASS 10 for submersible pumps or high-inertia loads that accelerate quickly, CLASS 20 for longer ramp times on conveyors or crushers.
The recommended orientation is vertical on a horizontal mounting rail, though any position is permitted. Dimensions are 45 mm wide by 170 mm high by 165 mm deep — a 45 mm footprint that fits a standard 4-module-wide slot in a distribution board. Main circuit connection is plug-in without terminals, so you need the matching Siemens terminal block set. The conductor cross-section accepted is 0.5 to 4 mm² solid, or 2x 0.5 to 2.5 mm² when doubling up — typical for a 32 A motor circuit on 4 mm² stranded.
Vibration resistance is specified at 4 to 5.8 Hz with 15 mm amplitude, and 5.8 to 500 Hz at 20 m/s² for 10 cycles. Shock resistance is 60 m/s² (6 g) with 10 ms half-sine pulses, three shocks per axis. These ratings cover the mechanical stress typical of conveyor-adjacent panels or machine-mounted enclosures. Two LEDs on the front indicate status — one for the control voltage present, one for the overload trip condition. No IO-Link or AS-Interface protocol is built in, so communication is limited to hardwired start/stop and feedback contacts.
The 3RA6120-1EE33 is a current-lifecycle part.