The Siemens SIRIUS 3RK1315-6KS71-2AA3 is a direct motor starter — a self-contained unit that combines a contactor and overload relay in one IP65 housing, designed for starting and protecting three-phase motors up to 0.75 kW at 400 V or 0.7 hp at 460/480 V.
Integration and connectivity
Communication runs over AS-Interface, a two-wire bus that carries both power and data to the starter — no separate control cable needed for the coil. Device addressing is done via an M12 plug on the unit. The main power circuit connects through a HAN Q4/2 plug conforming to ISO 23570, so the power cable is a factory-made harness, not field-wired into the housing. Four digital inputs and one digital output are available for local sensors or actuators. Supply voltage is 24 V DC nominal, with a permissible range of 20.4 to 28.8 V. The unit accepts screw fixing and can be mounted vertically, horizontally, or flat — the recommended orientation is horizontal for optimal heat dissipation.
Panel space should be checked against these dimensions before committing the cutout. The unit withstands vibration of 7 mm / 2g and shock of 12g for 11 ms, making it suitable for mounting on machinery that sees moderate mechanical stress. The ON-delay is 25 ms and the OFF-delay is 35 ms — these are fixed, not adjustable, so sequence timing in the PLC program must account for them if the starter is used in a fast interlock chain.