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Siemens 3RK4320-3CR51-0BA0 — Motor Starters

Siemens 3RK4320-3CR51-0BA0 SIRIUS Motor Starter

MPN3RK4320-3CR51-0BA0

Siemens SIRIUS motor starter MCU for AS-Interface, 3RK4320-3CR51-0BA0, direct starter design, 1 A rated at AC-3 400 V, IP55, Trip Class 10, 340-440 V operating voltage.

Siemens 3RK4320-3CR51-0BA0 datasheet (PDF)
Sourced new & surplus through independent channelsAuthenticity-screened · ESD-safe packingListing updated Aug 2026

Specifications

3RK4320-3CR51-0BA0 — Identification
ParameterValue
Product designationmotor starter MCU for AS-Interface
Main circuit poles3
BrandSIRIUS
Product design / constructiondirect starter
Reference designation (IEC 81346-2)Q
3RK4320-3CR51-0BA0 — Protection & Tripping
ParameterValue
Trip classCLASS 10
Overload release setting range (current)0.7 ... 1 A
Duty / utilization type (IEC 60947-6-2)1
3RK4320-3CR51-0BA0 — Contacts & Control
ParameterValue
Switching contact typeelectromechanical
3RK4320-3CR51-0BA0 — Communication
ParameterValue
AS-Interface protocol supportYes
3RK4320-3CR51-0BA0 — Mechanical & Connection
ParameterValue
Main circuit connection typescrew-type terminals
Mounting position+/-180° rotation possible on vertical mounting surface; can be tilted forward and backward by +/- 22.5° on vertical mounting surface
Width182 mm
Height220 mm
Depth145 mm

Product details

The operating voltage range is 340 to 440 V, with the control supply running on 20.4 to 26.4 V DC. The bimetal motor protection element handles the thermal model directly. IP55 enclosure means it handles dust ingress and water jets from any direction, suitable for installation in industrial environments where occasional washdown or hose-down cleaning occurs, though not rated for full immersion or high-pressure spray.

Fieldbus and integration

This starter communicates via AS-Interface protocol — no PROFINET or PROFIBUS DP on board. The AS-Interface bus carries both the control commands and the status feedback over a single two-wire cable, simplifying wiring in distributed I/O architectures. For plants already running AS-i, this drops straight into the network segment. The three-pole main current circuit handles the motor load. Short-circuit protection is provided by upstream circuit breakers.

Frequently asked questions

Is the Siemens 3RK4320-3CR51-0BA0 a direct starter or a reversing starter?

It is a direct starter. The product design is explicitly listed as a direct starter, not a reversing or star-delta configuration. For reversing applications, you would need a second contactor and mechanical interlock.

What voltage does 3RK4320-3CR51-0BA0 operate on?

The main circuit operating voltage is 340 to 440 V AC at 50/60 Hz. The control supply voltage is 20.4 to 26.4 V DC. The AS-Interface bus also provides power for the electronics.

Does the 3RK4320-3CR51-0BA0 support PROFINET or PROFIBUS?

No. This motor starter supports AS-Interface protocol only. It does not support PROFINET or PROFIBUS DP. For PROFINET or PROFIBUS connectivity, a gateway or a different SIRIUS variant with the appropriate communication module would be needed.

What is the mounting orientation for SIRIUS MCU starter 3RK4320?

The mounting position allows ±180° rotation on a vertical mounting surface and ±22.5° tilt forward or backward on a vertical surface. This flexibility helps fit the starter into confined cabinet spaces or align cable entries.

Where can I buy the Siemens 3RK4320-3CR51-0BA0 motor starter?

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

MPN
3RK4320-3CR51-0BA0