The Siemens 3RK1323-5CS41-1AA0 is an ECOFAST reversing starter designed for motor control in distributed automation architectures. It combines mechanical switching contacts with solid-state electronic overload protection, rated for AC-3 duty up to 4 kW at 400 V, with an adjustable current range of 2.4 A to 9 A. The unit communicates over AS-Interface, making it a drop-in node for AS-i networks without requiring a separate PROFIBUS DP gateway.
The solid-state overload (type of motor protection) provides adjustable trip class and eliminates the bimetal drift of thermal relays — important for applications with frequent starts or varying ambient temperatures. The mechanical switching contacts handle the main current path; short-circuit protection is provided externally via fuses (design of short-circuit protection), so the panel builder must size and install the correct upstream fuses. This suits washdown environments, outdoor installations under cover, or food-and-beverage zones where hose-down cleaning is routine. AS-Interface bus communication (AS-interface protocol: Yes) means this starter is a slave on an AS-i network, carrying digital inputs (2x DC 24 V) and control signals over the two-wire flat cable. No PROFIBUS DP onboard — if the line uses PROFIBUS, a gateway is required. The bus communication function is built in, so no separate bus module is needed.
Reversing starters of this type are deployed in conveyor systems, hoists, door operators, and any application requiring forward/reverse motor control from a single device. The ECOFAST form factor is designed for distributed installation close to the motor — mounted on machine frames or in small junction boxes — rather than in a central MCC. The AS-Interface connection reduces field wiring to a single two-conductor cable carrying both power and data.
Sourcing is via quoted-to-order RFQ. Lead time should be confirmed against the project schedule. No official cross-reference or second-source exists in the evidence.
Integration notes
Dimensions are 130 mm wide, 250 mm high, and 91 mm deep. Tab terminals for the main circuit require female quick-connects.