The Siemens 3RK1300-1CS01-1AA1 is a SIRIUS EM 300 RS electromechanical reversing starter designed for ET 200X distributed I/O environments. Rated for AC-3 duty at 0.9 kW at 400 V, it handles reversing motor loads such as conveyors, hoists, and gate drives up to that power level. The setting range of 1.8 to 2.5 A via the bimetal overload relay lets you match the trip curve to the motor full-load current within that window. Operating voltage is 400 to 500 V AC, and the maximum short-circuit breaking capacity at 400 V is 50 A — the upstream protective device must coordinate to keep fault energy below that threshold.
AC-3 0.9 kW at 400 V is the motor-switching rating — this is the load the starter can make and break under typical induction-motor starting conditions. If your motor draws more than 2.5 A full-load or exceeds 0.9 kW, this unit is undersized. Not submersible, but fine for splashing and condensation. The integrated brake contact (DC 24 V / 3 A) is intended for externally supplied motor brakes — a common need on vertical-load axes or conveyors that must hold position when power is removed.
Bus communication and wiring
PROFIBUS DP is built in — no separate gateway module required. The starter connects directly to the ET 200X station bus, exchanging process data (start/stop/direction commands, fault feedback) over the fieldbus. AS-Interface is not supported on this variant. Main current circuit connects via tab terminals; the 9-pole motor feeder and 9-pole power connection are part of the assembly, simplifying wiring to the motor and brake.