What this SIRIUS reversing starter does on the line
The Siemens SIRIUS 3RK4320-3EQ51-1BA2 is a compact reversing motor starter designed for AS-Interface bus communication, integrating a contactor, overload relay, and reversing function into a single IP54-rated enclosure. Rated 1.6 A in AC-3 duty at 400 V, it switches motor loads up to that current — the Class 10 bimetal overload protects against sustained overcurrent, tripping fast enough for standard induction motors on conveyors, pumps, or small fans. The reversing contactor pair inside lets you change motor direction without an external interlock, saving panel space and wiring time.
AS-Interface integration and control supply
Communication runs over the AS-Interface protocol (the only bus this variant supports — no PROFIBUS or PROFINET onboard), so it drops straight into an existing AS-i network without a gateway. Control supply is 20.4 to 26.4 V DC, sourced from the AS-Interface yellow cable or a separate 24 V DC supply; the two digital inputs accept signals directly from the bus master or local sensors.