The Siemens 3RA1225-0KB23-1AV6 is a reversing combination starter from the SIRIUS family, frame size S0, rated for 0.9-1.25 A with a 24 VDC control voltage. This single device integrates a reversing contactor, overload relay, and disconnecting means in a compact DIN-rail or panel-mount package — one order code covers the full motor branch for a reversing application. The 24 VDC coil is standard for safety circuits and PLC-driven panels; the MSP auxiliary provides one SPDT NO/NC contact, and an additional NO contactor auxiliary is fitted front-mount.
The 0.9-1.25 A setting range governs the overload protection for the connected motor. That current window suits small reversing drives — conveyors, valve actuators, or positioning slides — where the full-load current falls within that band. Frame size S0 dictates the physical footprint and the busbar / terminal layout; verify panel cutout and DIN-rail clearance against your enclosure layout.
Listed under UL File E156943, Vol. 1, Sec. 14, confirming the device meets UL 508 requirements for industrial control equipment. The IEC designation means it also complies with IEC 60947-4-1 for motor starters. The CE mark is implied by the SIRIUS series listing.
Deployment context
Designed for DIN-rail or panel-mount installation in a control cabinet. The reversing function means two contactors interlocked mechanically and electrically — one for forward, one for reverse — with the overload relay common to both directions. The front-mounted auxiliary NO contact can be wired as a status feedback to the PLC or as a permissive in the safety circuit.