SIRIUS compact starter — 53 kA breaking capacity, adjustable trip class
The Siemens 3RA6120-2CP33 is a SIRIUS compact direct starter designed for continuous motor duty per IEC 60947-6-2. The adjustable trip class (Class 10 or 20) lets you match the overload protection to the motor start profile — Class 10 for fast-starting pumps and fans, Class 20 for high-inertia loads like conveyors or centrifuges. That flexibility is the main reason this starter replaces separate overload relay swaps in the panel.
Panel fit and wiring — 45 mm wide, 191 mm tall
At 45 mm wide, 191 mm tall, and 165 mm deep, this starter occupies a single 45 mm DIN rail slot — the same footprint as a standard contactor-plus-overload pair, but pre-integrated. The main circuit connects via plug-in terminals (no screw terminals on the power side), which speeds replacement: pull the old unit, snap in the new one, re-terminate the control wires. Solid wire capacity is 2x (0.25 to 1.5 mm²) on the control terminals. That's enough for standard 1.0 mm² or 1.5 mm² control wiring; if your panel uses 2.5 mm² for long runs, you'll need a ferrule or a terminal adapter. Mounting position is any orientation, though vertical on horizontal DIN rail is recommended. The shock rating of 60 m/s² (6g) for 10 ms across all axes and the vibration spec (15 mm displacement at 4–5.8 Hz, 20 m/s² acceleration at 5.8–500 Hz) mean it holds up in pump skids and conveyor sections without additional bracketing.
Control voltage and coil power — universal AC/DC, low standby draw
This simplifies stocking — one part number covers both 120 V and 240 V control systems common in North American and European panels. Coil power consumption is 6 W AC maximum and 5.1 W DC maximum. That's low enough to daisy-chain several starters on a single 24 VDC power supply without exceeding the supply's rating, though the coil is 110–240 V, not 24 V — plan your control transformer accordingly. Two onboard LEDs indicate coil status and trip condition — useful for quick fault isolation on the line without a meter.
Environmental range and compliance
Operating temperature spans -20 to +60 °C, storage and transport from -55 to +80 °C. Pollution degree 3 means it tolerates conductive dust and humidity typical of industrial enclosures without conformal coating.