SIRIUS direct starter for 60 mm busbar systems
The Siemens 3RA2120-4ED27-0AP0 is a SIRIUS direct online starter, size S0, designed for snapping onto 60 mm busbar systems — a common panel layout in IEC switchgear and motor control centres. The Class 10 trip characteristic means it will disconnect before the motor windings overheat under a locked-rotor condition — critical for standard induction motor starts.
Dimensions and clearance for panel fit
The unit measures 155 mm deep, 45 mm wide, and 260 mm tall. The narrow 45 mm width fits two units side-by-side in a standard 100 mm wide busbar chamber. Clearance requirements around the starter: 50 mm upwards, 20 mm forwards, 10 mm downwards, and 20 mm at the side. Zero clearance needed backwards — it sits flush against the busbar. These gaps allow for cooling airflow and tool access during wiring.
Supplied components and termination
This starter ships with a 3RT2027-1AP00 contactor and a 3RA2921-1AA00 link module pre-assembled. Operating temperature range is -20 to +60 °C; storage and transport range is -50 to +80 °C. Mounting position is vertical only.