The Siemens 3RK1300-0ES01-0AA3 is an EM 300 DS electromechanical direct starter designed for the ET 200X distributed I/O system. It's a motor-protective combination that integrates a contactor, bimetal overload relay, and short-circuit protection into one IP65-rated housing — meaning it lives directly on the machine or conveyor, not in a central panel. The setting range of 0.28 to 0.4 A covers small motors up to 0.1 kW at 400 V in AC-3 duty, so it's sized for fractional-horsepower drives like fans, small pumps, or indexing tables. The IP65 rating means the enclosure withstands hose-directed water and dust ingress — suitable for washdown zones or dusty environments on the plant floor. It communicates over PROFIBUS DP, so it reports motor status and fault conditions back to the controller without separate I/O wiring. A built-in motor brake output (product component Motor brake output: Yes) handles internally supplied DC brakes common on small servo or holding-brake motors, saving an external brake rectifier or contactor.
The AC-3 rating of 0.1 kW at 400 V defines the maximum three-phase induction motor it can start and stop under load. AC-3 is the standard duty for squirrel-cage motors — starting, running, and stopping during normal operation. The 0.28 to 0.4 A setting range on the bimetal overload matches the full-load current of a motor in that power band; you set it to the motor nameplate FLA. The maximum short-circuit breaking capacity (Icu) at 400 V is 50 A. Operating voltage range is 400 to 500 V AC. Ambient temperature during operation is 0 to 55 °C. That's typical for a non-conditioned enclosure on the plant floor; derate or add ventilation if the cabinet exceeds that.
The main current circuit uses tab terminals (Type of electrical connection for main current circuit: tab terminals), which is the standard quick-connect interface for the ET 200X motor feeder system. The 9-pole motor feeder and 9-pole power connection are part of the same modular bus system.