What this reversing starter is and where it fits
The Siemens 3RK1300-1CS01-1AA4 is an electromechanical reversing starter from the SIRIUS EM 300 RS family, designed for the ET 200X distributed I/O system. It combines a reversing contactor pair with bimetal motor protection in a single IP65 enclosure, rated for direct-on-line reversing of three-phase motors up to 0.9 kW at 400 V AC-3 duty. The bimetal overload relay sets between 1.8 A and 2.5 A full-scale, matching the motor FLA in that window. The 50 A short-circuit breaking capacity at 400 V (Icu) means the upstream protection can be a circuit breaker or fuse sized to that fault level without the starter itself failing catastrophically. PROFIBUS DP onboard handles the bus communication, so this unit connects directly to the ET 200X backplane without a separate gateway. The integrated motor brake output (DC 500 V / 1 A) is for internally supplied brakes — common on small conveyor and hoist drives where the brake coil shares the motor cable.
IP65 and washdown deployment
Rated IP65, the enclosure withstands hose-down cleaning and dusty environments. This starter mounts directly in the field near the motor — no separate control cabinet needed — which is the whole point of the ET 200X distributed architecture. The 134 mm depth and 140 mm width fit the standard ET 200X footprint; the 270 mm height accommodates the reversing contactor stack and brake contactor. Tab terminals on the main current circuit accept fork or ring lugs. The operating temperature range is 0 to 55 °C.