Siemens 3RA1120-4AA25-0BB4 is a SIRIUS combination starter that integrates a motor starter with a fuseless load feeder for direct-on-line motor starting at 400 V AC. Designed for control cabinets, this compact S0-size package consolidates the protective and switching functions needed to energize small- to mid-size three-phase motors in pumps, fans, conveyors, and machine tools, reducing wiring complexity and panel space. The 3RA1120 family is specified for direct-on-line starting, and the 4AA25-0BB4 variant denotes a fuseless load feeder configuration within this series, aligning with Siemens documentation for direct starters.
