The Siemens 3RK1300-0CS01-1AA1 is an EM 300 RS electromechanical reversing starter designed for the ET 200X distributed I/O system. It integrates a reversing contactor, bimetal overload relay, and PROFIBUS DP communication into a single IP65-rated enclosure — a self-contained motor control unit for small reversing loads in washdown or dusty environments. Rated at 0.06 kW in AC-3 duty at 400 V, it covers small three-phase motors — pumps, conveyors, or valve actuators — where space and sealing matter more than a panel-mounted contactor pair. The setting range of 0.18 to 0.25 A matches the motor full-load current directly via the bimetal relay.
The 0.06 kW AC-3 rating at 400 V defines the maximum three-phase induction motor this starter can switch under normal starting conditions. AC-3 covers starting and plugging of squirrel-cage motors — the dominant duty for reversing starters. Operating voltage spans 400 to 500 V. The 0 to 55 °C ambient range suits most indoor industrial environments. The 9-pole motor feeder and 9-pole power connection are tab terminals, so panel wiring uses standard quick-connect receptacles.
Brake output and PROFIBUS integration
This variant includes a motor brake output rated DC 24 V / 3 A for externally supplied brakes — common on vertical-axis conveyors or hoists where the brake must engage when the motor is de-energized. The brake contact is integrated into the reversing starter, eliminating a separate brake relay. PROFIBUS DP communication is built in, so the starter connects directly to a PROFIBUS DP master without a separate gateway. This is the ET 200X ecosystem's native fieldbus — the starter appears as a distributed I/O device on the bus, with control and status data mapped into the PLC's process image.
It mounts directly to the ET 200X backplane or to a mounting plate via the enclosure's fixing points.