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Siemens 3RA2125-4AE26-0FB4 — Motor Starters

Siemens 3RA2125-4AE26-0FB4 SIRIUS direct starter, 15.5 A

MPN3RA2125-4AE26-0FB4
Active

Siemens SIRIUS 3RA2125-4AE26-0FB4 direct on-line starter, size S0, 15.5 A AC-3 at 400 V, 24 V DC coil, Class 10, spring-loaded terminals, screw and snap-on 35 mm DIN rail.

Sourced new & surplus through independent channelsAuthenticity-screened · ESD-safe packingListing updated Jul 2026

Specifications

3RA2125-4AE26-0FB4 — Identification
ParameterValue
Product designationDirect (on-line) starter
Main circuit poles3
BrandSIRIUS
Load feeder sizeS0
Product design / constructionfor standard rail or screw mounting
Circuit-breaker sizeS0
Included contactor (type)3RT2026-2FB40
Included circuit-breaker (type)3RV2021-4AA25
Included link module (type)3RA2921-2AA00
3RA2125-4AE26-0FB4 — Ratings & Performance
ParameterValue
Rated motor power at 400 V7 500 kW
Rated voltage at AC-3, max.690 V
Rated operating frequency50 ... 60 Hz
Rated impulse withstand voltage (Uimp)6 kV
Rated insulation voltage Ui (AC, pollution degree 3)690 V
3RA2125-4AE26-0FB4 — Protection & Tripping
ParameterValue
Trip classCLASS 10
Short-circuit protectionYes
Rated short-circuit current at 400 V (IEC 60947-4-1)150 000 A
Overload release setting range (current)10 ... 16 A
Overload release typethermal (bimetallic)
Short-circuit trip typemagnetic
Duty / utilization type (IEC 60947-6-2)2
3RA2125-4AE26-0FB4 — Contacts & Control
ParameterValue
Rated value24 ... 24 V
Control supply voltage typeDC
Auxiliary contacts, NO1
Auxiliary contacts, NC1
Auxiliary switch extensionYes
Switching contact typeelectromechanical
3RA2125-4AE26-0FB4 — Communication
ParameterValue
AS-Interface protocol supportNo
3RA2125-4AE26-0FB4 — Mechanical & Connection
ParameterValue
Mounting / fastening methodscrew and snap-on mounting onto 35 mm DIN rail
Mounting positionvertical
Width45 mm
Height243 mm
Depth107 mm
3RA2125-4AE26-0FB4 — Environmental
ParameterValue
Operating temperature range-20 ... +60 °C
Storage temperature range-50 ... +80 °C
Transport temperature range-50 ... +80 °C
Shock resistance (IEC 60068-2-27)6g / 11 ms

Product details

The Siemens 3RA2125-4AE26-0FB4 is a SIRIUS direct on-line starter, size S0, combining a contactor and overload relay in one assembly for switching and protecting three-phase motors. The thermal bimetallic overload provides Class 10 trip protection — fast enough for most pump, fan, and conveyor starts. The 24 V DC coil (rated value 24... 24 V) holds in at nominal voltage; verify the control supply stays within the operating range of -20 to +60 °C.

Dimensions: 45 mm wide, 243 mm tall, 107 mm deep — fits a standard S0 feeder footprint. Both main and auxiliary/control circuits use spring-loaded terminals — no screwdriver torque needed, faster wiring in panel builds. Accepts solid or ferruled stranded conductors.

Frequently asked questions

Does the 3RA2125-4AE26-0FB4 include a diode combination?

The evidence does not specify a diode combination. The coil is rated 24 V DC; verify surge suppression requirements separately for your control circuit.

Is the 3RA2125-4AE26-0FB4 compatible with 3RV2 circuit breakers?

Yes, the supplied circuit breaker is a 3RV2021-4AA25, which is a 3RV2 size S0 breaker. The starter is designed for direct integration with that breaker family.

Where can I buy 3RA2125-4AE26-0FB4 available via RFQ confirmation?

This part is sourced to order. Availability and pricing are confirmed at quote time.

MPN
3RA2125-4AE26-0FB4