What this reversing starter does on the line
The Siemens 3RK1300-1FS01-1AA3 is an electromechanical reversing starter from the EM 300 RS family, designed for the ET 200X distributed I/O system. It combines two contactors, a bimetal overload relay, and a motor brake output in one IP65 enclosure — meaning it sits directly on the machine or conveyor, not in a central panel. The setting range of 3.5 to 5.0 A covers small three-phase motors up to 1.9 kW at 400 V in AC-3 duty (squirrel-cage motors, normal starting). That AC-3 rating is the one that matters for motor switching: it's rated for making and breaking locked-rotor current, so it handles the inrush on a pump, fan, or small conveyor without derating.
Bus integration and brake contact
This starter communicates over PROFIBUS DP, so it plugs into the ET 200X bus node and gets its start/reverse commands from the PLC without hardwired control wires. The integrated motor brake output supplies AC 400 V internally for spring-applied brakes — common on vertical-axis conveyors or hoists where the brake must engage when power drops. The main current circuit connects via tab terminals, which mate with the ET 200X power distribution module; no screw terminals to torque on the motor feeder.
Short-circuit protection and coordination
Short-circuit protection is designed around circuit-breakers, not fuses. The maximum short-circuit breaking capacity (Icu) at 400 V is 50 A — that's the fault current this starter can safely interrupt when paired with an upstream breaker. For a typical 1.9 kW motor drawing about 4 A full-load, that gives substantial headroom for a Type 1 or Type 2 coordination scheme. The IP65 rating means the housing withstands washdown environments, so it's suited for food-and-bev or automotive lines where hose-down cleaning is routine.