What this part is and what it does
The Siemens 3RK1300-1BS01-1AA0 is an electromechanical reversing starter from the SIRIUS EM 300 RS family, designed for the ET 200X distributed I/O system. It combines two contactors and a bimetal overload relay in a single IP65 enclosure, so it can be mounted directly on the machine frame or conveyor line without a separate control panel — the IP65 rating means the housing and all connections withstand washdown environments, making it suitable for food-and-bev or wet-area deployment. Rated at 0.75 kW in AC-3 duty at 400 V, it switches standard three-phase squirrel-cage motors up to that power. The bimetal overload sets between 1.4 A and 2.0 A full-scale, matching the motor full-load current for that power class. The operating voltage range is 400...500 V AC. Built-in PROFIBUS DP communication lets the starter exchange status and control signals directly with a PLC over the fieldbus, eliminating separate I/O wiring for each motor branch. The main circuit connects via tab terminals, which is the standard faston-style interface for the ET 200X power bus.
Physical fit and integration
Dimensions are 140 mm wide, 270 mm high, 134 mm deep. The IP65 enclosure is self-contained — no DIN-rail mounting required; it bolts directly to a machine frame or mounting plate. The 134 mm depth is the critical dimension for shallow enclosures or tight spaces between machine guards. Tab terminals for the main circuit match the standard ET 200X power tap-off system, so panel builders can plug it into the pre-wired power bus without cutting and crimping individual wires.
Short-circuit coordination
The maximum short-circuit breaking capacity (Icu) at 400 V is 50 A. This means the starter can safely interrupt a fault current up to 50 A without upstream devices needing to clear it first — a key number for selectivity studies. The short-circuit protection design uses circuit-breakers, not fuses, so the coordination is with a molded-case or miniature circuit breaker upstream. Ambient operating range is 0...55 °C.