SIRIUS S0 direct starter for 60 mm busbar systems
The Siemens 3RA2120-1FD24-0AP0 is a SIRIUS S0 direct online starter — a pre-assembled unit combining a contactor and overload relay in one package, designed for snapping onto 60 mm busbar systems. It ships with a 3RT2024-1AP00 contactor and a 3RA2921-1AA00 link module, so the coordination between the switching and protection elements is factory-set.
CLASS 10 trip and AC-3 duty ratings
Rated for AC-3 duty up to 690 V, the starter handles the high inrush of motor starting and the lower running current of the full-load condition. At 480 V it is rated 5 A (3 hp), at 600 V also 5 A (5 hp), and at 230 V it delivers 0.5 hp — the current ceiling stays at 5 A across the higher voltage range, so the motor full-load amps must be at or below that figure.
Busbar snap-on and panel clearances
Fastening method is snap-on for 60 mm busbar systems — no DIN rail adapter needed, which saves rail space and reduces wiring in a motor control centre. Dimensions are 260 mm high × 45 mm wide × 155 mm deep, with required clearances of 50 mm upward, 20 mm forward, 10 mm downward, and 20 mm at the side for airflow and arc flash mitigation. Mounting position is vertical; the operating temperature range is -20 to +60 °C, with storage and transport limits of -50 to +80 °C.