The Siemens 3RK1300-1AS01-1AA0 is an EM 300 RS electromechanical reversing starter designed for the ET 200X distributed I/O system. It combines a reversing contactor, bimetal motor protection, and PROFIBUS DP communication in a single IP65-rated enclosure, meaning it lives directly on the machine or conveyor section, not in a central panel. Rated for a 0.55 kW motor at AC-3 duty on a 400-500 V supply, it covers small reversing loads — conveyors, small hoists, gate drives — where direction change is needed and the motor protection must be local. The setting range of 1.1 to 1.6 A matches the full-load current of a 0.55 kW motor at 400 V.
The 0.55 kW rating at AC-3 (400 V) is the motor-switching capability under starting and reversing duty — the load the contacts see during inrush and plugging. That is the figure to match against your motor nameplate, not the thermal setting range. The 1.1 to 1.6 A thermal bimetal adjustment protects the motor against sustained overload; set it to the motor's full-load amps. The maximum short-circuit breaking capacity (Icu) at 400 V is 50 A.
The 3RK1300-1AS01-1AA0 is designed for the ET 200X system — it plugs into the motor feeder and power connection via 9-pole interfaces. Main current circuit connections use tab terminals, so expect fast-on connectors rather than screw clamps. The PROFIBUS DP connection handles bus communication; there is no AS-interface on this variant. Dimensions are 140 mm wide, 270 mm high, and 134 mm deep. That 140 mm width is the critical panel-space dimension — it occupies roughly the space of two standard contactors side-by-side, plus the enclosure. Verify clearance for the 270 mm height in your junction box or machine frame.