The Siemens 3RK1300-1AS01-0AA0 is an EM 300 DS direct starter from the SIRIUS family, designed for the ET 200X distributed I/O system. It's an electromechanical direct starter with a bimetal motor protection element, setting range of 1.1 to 1.6 A, and rated for AC-3 duty at 0.55 kW / 400 V. This is a motor feeder packaged for remote or on-machine mounting — it carries PROFIBUS DP communication onboard, so you get start/stop and fault feedback over the bus without pulling separate control wires back to the cabinet.
What the ratings mean for fit
The 1.1 to 1.6 A setting range covers small motors up to 0.55 kW at 400 V in AC-3 switching duty — that's your standard squirrel-cage induction motor starting, not resistive heating. The bimetal overload relay inside gives inverse-time thermal protection, so it tracks the motor's heating curve naturally. The IP65 rating means the whole enclosure is dust-tight and protected against low-pressure water jets — this starter is meant to live on the machine, not in a climate-controlled cabinet. It's rated for an ambient operating temperature of 0 to 55 °C. The maximum short-circuit breaking capacity (Icu) at 400 V is 50 A. That's the fault current the unit can safely interrupt without welding its contacts or rupturing the enclosure. In practice, you'll still need an upstream circuit breaker sized to keep prospective fault current below that level — the part itself uses circuit-breaker type short-circuit protection per its design. Main circuit connections are tab terminals, which suits the ET 200X system's plug-in power distribution approach. The 9-pole motor feeder and 9-pole power connection mean this module drops into the ET 200X backplane and connects to the motor via a pre-wired connector — no individual wire termination for each phase.
Where it's used
This direct starter is for distributed motor control in applications where the motor is remote from the main control panel. Think conveyor drives, small pumps, fans, and agitators on a production line. Because it's IP65 and communicates over PROFIBUS DP, it mounts directly on the machine frame or a nearby stanchion, pulling power and bus from the ET 200X backbone. It eliminates a separate motor starter enclosure and the home-run control wiring back to the MCC.