What this direct starter does on an ET 200X node
The Siemens 3RK1300-0DS01-0AA4 is an EM 300 DS electromechanical direct starter designed for the ET 200X distributed I/O system. It combines a contactor, bimetal overload relay, and short-circuit protection (via circuit-breakers) into one IP65-rated enclosure. The setting range covers 0.22 A to 0.32 A, corresponding to AC-3 motor duty at 0.09 kW on a 400 V line. Operating voltage is 400... 500 V. The part communicates over PROFIBUS DP, so it integrates directly into a Siemens PLC network without a separate gateway. The bimetal overload element provides thermal motor protection, and the built-in motor brake output (DC 500 V / 1 A) handles internally supplied brakes — a common requirement for holding brakes on vertical-axis drives. The operating ambient temperature range is 0... 55 °C.
Dimensions are 140 mm wide, 270 mm high, and 134 mm deep. The main current circuit connects via tab terminals. The 9-pole motor feeder and 9-pole power connection mate with the ET 200X backplane; no field wiring to the motor is required beyond the pre-terminated cable assembly. The short-circuit breaking capacity is rated at 50 A at 400 V — coordinate upstream protection to clear faults below that threshold. The design uses circuit-breakers for short-circuit protection rather than fuses, which simplifies reset after a fault.