Reversing starter with PROFIBUS DP and IP65 enclosure
The Siemens 3RK1303-5BS41-1AA3 is a reversing starter with solid-state motor protection, rated 3 A at 400 V in AC-3 duty — that's the motor-switching current for a reversing application, not the resistive load rating. It integrates a PROFIBUS DP interface for fieldbus control and is housed in an IP65-rated enclosure, so it can be mounted directly on a machine frame or in a washdown zone without an additional cabinet.
Fieldbus and I/O configuration
Communication uses PROFIBUS DP (no PROFINET on this variant). The unit carries two digital inputs via M12 sockets, parameterizable, and zero digital outputs — the reversing contactor is driven internally by the solid-state logic. Supply voltage is 24 V DC nominal, with a permissible range of 20.4 to 28.8 V DC. The main energy infeed and load-side outgoing feeder use sockets per ISO 23570; the supply voltage line-side and communication interface use hybrid plugs and sockets.
Dimensions and mounting
The housing measures 250 mm high, 130 mm wide, and 107 mm deep — a compact footprint for a reversing starter with integrated bus and IP65 sealing. It is designed for direct machine mounting, not DIN-rail; the hybrid connectors for supply and communication are keyed to the enclosure.