The Siemens 3RK1300-0CS01-1AA4 is an EM 300 RS electromechanical reversing starter designed for the ET 200X distributed I/O system. It integrates a bimetal motor protection relay, reversing contactor pair, and PROFIBUS DP communication into a single IP65 enclosure — a self-contained motor control unit for a reversing drive in a washdown zone. Rated at 0.06 kW at AC-3 duty on a 400 V supply, it handles the reversing of small three-phase motors — conveyors, diverters, or gate actuators — up to that load. The setting range of 0.18 to 0.25 A matches the full-load current of the motor, and the bimetal overload provides Class 10 trip protection. The tab terminals for the main circuit accept standard fast-on connectors, keeping field wiring quick.
The maximum short-circuit breaking capacity (Icu) at 400 V is 50 A. The design assumes circuit-breaker backup per the product spec. Operating voltage is 400 to 500 V AC. Coil voltage type is DC.
This reversing starter is a module in the Siemens ET 200X family — it connects to the system via a 9-pole motor feeder and a 9-pole power connection, and communicates over PROFIBUS DP. The brake contact output (DC 500 V / 1 A) is intended for internally supplied DC brakes on the motor, common in holding-brake applications for vertical axes. Dimensions are 140 mm wide, 270 mm high, and 134 mm deep — it occupies a footprint similar to a small contactor but with the added depth of the bus interface and enclosure. The IP65 housing allows direct mounting on the machine, but the tab terminals and bus connector must be accessible for wiring and service.
The narrow 0.18 to 0.25 A band means a motor with a slightly higher FLA requires a different starter variant.