Busbar snap-on and panel fit — the dimensions that decide
The 3RA2220-1HD24-0AP0: This unit snaps onto 60 mm busbar systems — it's not a DIN-rail mount, so the panel layout needs the busbar grid, not a standard top-hat rail.
Trip Class 10 and the horsepower range it covers
Trip Class 10 means the overload relay trips within 10 seconds at 600% of the set current — standard for general-purpose motor starting where the load doesn't have a long acceleration ramp. The horsepower range spans 1 hp at 230 V up to 7.5 hp at 575/600 V, with the AC-3 maximum voltage rated at 690 V. That covers most 480 V and 600 V motor applications in North America and 400 V in Europe, all through one reversing starter package.
What's in the box — pre-assembled contactor and link module
The reversing starter ships with the contactor 3RT2024-1AP00 and link module 3RA2921-1AA00 already assembled — no field wiring of the mechanical interlock. Temperature compensation is active across the -20 to +60 °C operating range, which keeps the trip curve stable in a warm panel.