The Siemens 3RA1125-1DA23-1BB4 is a nonreversing combination starter in the SIRIUS family, frame size S0, designed for DIN-rail or panel mounting in IEC control panels. It integrates a motor starter protector (MSP) and a contactor in one unit, rated for a motor current range of 2.2 to 3.2 A. The control voltage is 110 VDC, so the coil is sized for a DC control circuit — verify your control transformer or PLC output card supplies clean DC at that level, not rectified AC. The MSP auxiliary is 1 SPDT (NO/NC), and the contactor carries an additional 1 NO front-mounted auxiliary. UL file E156943 covers the starter for North American acceptance.
Siemens 3RA1125-1DA23-1BB4 Combination Starter, 2.2-3.2A
MPN3RA1125-1DA23-1BB4
Siemens SIRIUS 3RA1125-1DA23-1BB4, nonreversing combination starter, DIN/panel mount, frame size S0, 2.2-3.2 A, 110 VDC control voltage, with MSP auxiliary and contactor auxiliary contacts.
Sourced new & surplus through independent channelsAuthenticity-screened · ESD-safe packingListing updated Jul 2026
Product details
Frequently asked questions
What is the current rating of 3RA1125-1DA23-1BB4?
The motor current setting range is 2.2 to 3.2 A. This is the adjustable overload trip window on the motor starter protector.
How to wire Siemens 3RA1125-1DA23-1BB4 combination starter?
Wiring follows standard SIRIUS S0 combination starter practice: the MSP line-side terminals connect to the supply, the contactor load-side terminals connect to the motor. The 110 VDC coil is wired through the control circuit, and the auxiliary contacts (1 SPDT on the MSP, 1 NO on the contactor) are available for status feedback or interlocking. A wiring diagram is part of the product documentation available from Siemens.
MPN
3RA1125-1DA23-1BB4