BOM fit — AC-3 motor rating and trip class
The 3RA2120-4BE26-0BB4: That means it switches squirrel-cage motors up to 20 A under full-load starting conditions without welding the main contacts. If the load has a long acceleration ramp (high-inertia fans), a Class 20 or 30 starter would be needed. The horsepower equivalents span 1.5 hp at 110/120 V up to 20 A at 480/600 V, so it covers a range of common North American and IEC motor frames. Match the FLA on the motor nameplate to the 20 A ceiling.
Integrated assembly — contactor and link module included
The starter ships with the contactor 3RT2026-2BB40 and the link module 3RA2921-2AA00 already matched — no separate sizing of contactor and overload relay. The size S0 circuit-breaker interface is built in. Main circuit connections use spring-loaded terminals, so you land the power wires without torquing screws — useful in high-density panels where screw access is tight. The control coil is 24 V DC, the standard for PLC-driven panels.
Mounting and clearances
Mounts vertically on 35 mm DIN rail with a screw and snap-on fastening. The footprint is 45 mm wide by 243 mm tall by 107 mm deep — it fits a standard S0 feeder slot. Required clearances: 50 mm above, 20 mm below, 20 mm to the sides, 20 mm forward, zero backward. Plan the enclosure depth to leave at least 107 mm plus wiring space behind the door.