Motor switching duty and the AC-3 rating
The 3RA2120-1HA24-0BB4: AC-3 is the standard category for squirrel-cage motor starting — the contacts make under inrush and break at full-load current, so the 8 A figure governs the largest standard induction motor this unit can switch across the line.
Panel fit and mounting constraints
The unit occupies 45 mm of DIN-rail width — the critical dimension for rail layout in a crowded panel. Overall dimensions are 107 mm depth, 45 mm width, and 193 mm height. Clearance requirements: 50 mm upwards, 20 mm forwards, 20 mm at the side, 10 mm downwards, and 0 mm backwards. The zero backward clearance means the unit can be mounted flush against a panel backplate or busbar support.
Pre-assembled unit — what is inside
The starter ships as a factory-assembled combination: a 3RT2024-1BB40 contactor and a 3RA2921-1BA00 link module, mounted on an S0-size feeder. The circuit-breaker size is S00. For MRO planning, these are the individual replacement part numbers if a component fails in service. The main circuit connections are screw-type terminals.
Sourcing and lifecycle status
Operating temperature range is -20 to +60 °C, with storage and transport range from -50 to +80 °C. The unit is designed for standard rail or screw mounting in a vertical orientation.