What this reversing starter is and where it lands
The Siemens 3RK1300-1KS01-1AA1 is an electromechanical reversing starter from the SIRIUS EM 300 RS family, designed for the ET 200X distributed I/O system. It combines two contactors, a bimetal overload relay, and a motor brake output in a single IP65 enclosure — meaning it mounts directly on the machine frame or in a field-distribution cabinet, not inside a central control panel. The bimetal motor protection covers a setting range of 9 to 12 A, and the unit is rated for 5.5 kW at 400 V in AC-3 duty (the standard motor-switching category per IEC 60947-4-1), so it handles reversing and braking of three-phase induction motors up to that power.
Key ratings and what they mean for fit
The 5.5 kW AC-3 rating at 400 V is the headline motor-switching capacity — it governs which motor frame sizes this starter can reverse and protect. The 9 to 12 A overload setting range means the bimetal relay is field-adjustable to match the motor full-load current within that window; if your motor draws 10.5 A FLA, you set the dial to 10.5 A, and the relay tracks the thermal load. The operating voltage of 400 to 500 V AC covers standard European 400 V three-phase networks and 480 V North American systems. IP65 means the housing is dust-tight and protected against low-pressure water jets — suitable for washdown zones or outdoor installation without an additional enclosure.
PROFIBUS DP and integrated brake output
This starter communicates over PROFIBUS DP, so it plugs into a PROFIBUS segment as a slave device — the PLC sends direction and start/stop commands over the bus, and the starter reports back status and overload trips. The integrated motor brake output (DC 24 V / 3 A) is intended for externally supplied holding brakes on vertical-axis motors or conveyors; the brake contact is wired through the 9-pole motor feeder cable, which also carries the motor power and feedback signals. The 9-pole power connection mates with the ET 200X backplane or a pre-wired distribution block, reducing field wiring to a single cable run per starter.
Mounting and environmental limits
Dimensions are 270 mm high, 140 mm wide, and 134 mm deep — a compact footprint for a reversing starter with integrated bus and brake output. The ambient operating range is 0 to 55 °C, which covers most industrial floor conditions but not freezer or high-temp foundry environments. The short-circuit breaking capacity (Icu) at 400 V is 50 A; this is the maximum fault current the device can interrupt without damage, so upstream protection must be coordinated to keep prospective fault current below that level.