The Siemens 3RK1300-1ES01-1AA1 is an electromechanical reversing starter from the SIRIUS 3RK1 family, designed for the ET 200X distributed I/O system. It combines a reversing contactor, bimetal overload relay, and PROFIBUS DP communication in a single IP65-rated enclosure, so it mounts directly on the machine frame rather than in a central panel. The setting range of 2.8 to 4.0 A means you dial in the full-load current of the motor — the bimetal overload follows that setting, not a fixed trip point.
AC-3 covers starting and plugging of squirrel-cage motors, which is the typical reversing duty cycle. The short-circuit breaking capacity (Icu) is 50 A at 400 V. If the available fault current upstream exceeds 50 A, you need a current-limiting circuit breaker ahead of it — the design expects circuit-breaker short-circuit protection. Operating voltage range is 400 to 500 V, which covers standard European 400 V three-phase networks and 480 V North American systems. The control voltage for the brake output is DC 24 V at 3 A — that's a separate circuit for an externally supplied motor brake, not the main contactor coil. Ambient temperature range of 0 to 55 °C means it's fine in an unventilated machine enclosure but not for freezer applications or direct sun in a desert plant.
Integration into the ET 200X system
This starter connects to the ET 200X backplane via a 9-pole motor feeder and a 9-pole power connection — it's not a standalone device; it needs the ET 200X bus interface module to communicate. The PROFIBUS DP protocol is built in, so it exchanges status and control data directly with the PLC over the fieldbus without a separate gateway. The main circuit connections use tab terminals, which are common in distributed motor starter blocks — they accept standard quick-connect receptacles or can be crimped with fork terminals. No screw terminals on the power side. Dimensions are 140 mm wide, 270 mm high, and 134 mm deep. That's a compact footprint for a reversing starter with integrated brake output and bus communication — it fits in the ET 200X mounting rail system without crowding adjacent modules.