The Siemens 3RK1300-1JS01-1AA3 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 a bimetal overload relay in a single IP65 enclosure, rated for washdown environments on conveyors, material handling, and packaging lines. Setting range is 7.0-10A, delivering 4.0kW at AC-3 duty on a 400V supply. The 7.0-10A adjustment window means the bimetal overload is sized for motors drawing 7-10A full-load current at 400V — typically a 4kW 4-pole induction motor. The AC-3 rating (starting and stopping running motors) is the relevant duty cycle; AC-1 resistive loads would allow higher current but this part is intended for motor reversing applications. PROFIBUS DP communication is built in, so this unit connects directly to a PROFIBUS DP master without an external gateway. The operating voltage range is 400-500V AC, covering 400V and 480V nominal systems. Ambient operating temperature is 0-55°C, suitable for most industrial enclosures without active cooling.
Brake output and wiring
This reversing starter includes a motor brake output for holding brakes — the 9-pole motor feeder carries both the motor power leads and the brake control wiring, simplifying the cable run to the motor. The main current circuit uses tab terminals, typical for quick-connect installation inside a junction box or control cabinet. The 9-pole power connection mates with the ET 200X interface module.
Short-circuit protection and breaking capacity
Short-circuit protection is designed around circuit-breakers (not fuses), with a maximum short-circuit breaking capacity of 50A at 400V. That 50A Icu means the unit can safely interrupt a fault current up to 50A without upstream coordination — adequate for most motor branch circuits fed from a 16-25A MCCB. For higher available fault currents, verify the upstream breaker's let-through is below 50A.
Physical dimensions and mounting
The enclosure measures 134mm deep, 140mm wide, and 270mm high. The compact footprint allows it to fit in shallow junction boxes or alongside other ET 200X modules. The IP65 rating means it can be mounted directly on the machine frame or conveyor structure without an additional enclosure — the housing is dust-tight and protected against water jets from any direction.