What it is and what it does
The Siemens 3RK1300-1ES01-1AA3 is an electromechanical reversing starter from the SIRIUS EM 300 RS family, designed for the ET 200X distributed I/O system. It integrates a reversing contactor pair, bimetal overload protection, and a brake contact output into a single IP65 enclosure — meaning it lives directly on the machine, not in a central panel. Rated for 1.5 kW at AC-3 duty at 400 V, with a setting range of 2.8 to 4.0 A, it handles small reversing motor loads — conveyors, gates, turntables — where you need direction change and overload protection in one package. The built-in brake contact (product component motor brake output) supplies an internally powered DC brake, saving an external relay. Communication runs over PROFIBUS DP, so the starter is addressable from the PLC for start/stop and direction commands.
Where it fits
This is a field-mounted unit — IP65 lets it sit on the machine frame or in a small junction box near the motor, not in a climate-controlled cabinet. The main current circuit connects via tab terminals; the 9-pole motor feeder and 9-pole power connection are part of the ET 200X plug system. Dimensions: 270 mm high, 140 mm wide, 134 mm deep. That depth is the key clearance number when fitting into a shallow enclosure or under a machine shroud. Operating temperature range is 0 to 55 °C — fine for most factory-floor environments but not for freezers or ovenside locations.
Short-circuit coordination
The maximum short-circuit breaking capacity (Icu) at 400 V is 50 A. That is the fault level the integrated circuit-breaker-style short-circuit protection can interrupt — coordinate upstream to stay within that limit.