Active SIRIUS reversing starter, S0 frame
The 3RA2220-4NF27-0AP0: This is a Siemens SIRIUS reversing starter, size S0, combining two contactors and a mechanical interlock in one assembly for forward/reverse motor control. It ships with the 3RT2027-2AP00 contactor and 3RA2921-2AA00 link module pre-assembled.
Mounting and wiring constraints
Mounts vertically on a 35 mm DIN rail via the supplied adapter, or can be screw-mounted. The main circuit uses spring-loaded terminals — no screw torque to verify, but the stripped length and ferrule size matter for a gas-tight connection. Keep 50 mm clearance above, 32 mm in front, 10 mm at the sides, and 10 mm below for airflow and tool access. Dimensions are 269 mm high, 90 mm wide, 130 mm deep — the S0 frame fits standard distribution panels but check the backpanel depth before committing. Operating temperature range is -20 to +60 °C; storage and transport tolerance is -50 to +80 °C.