The Siemens 3RA2120-1JH24-0AP0 is a SIRIUS direct online starter, size S0, designed for snapping onto 60 mm busbar systems. It combines a contactor and overload relay into a single, pre-assembled unit for motor starting and protection in control panels. Rated for a maximum of 690 V AC-3, this starter handles motor loads up to 10 A at 600 V and delivers 7.5 hp at 460/480 V.
The starter snaps directly onto 60 mm busbar systems, a common panel layout for motor control centers. It requires 50 mm clearance upwards, 20 mm forwards, and 20 mm at the side for airflow and wiring access. The main circuit uses spring-loaded terminals, so no screw tightening is needed on the power connections. Mounting position is vertical only. The supplied contactor is a 3RT2024-2AP00 and the link module is 3RA2921-2AA00, so replacement parts are known if a component fails in the field.