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Siemens 3RK4320-3KQ51-0BA3 — Motor Starters

Siemens 3RK4320-3KQ51-0BA3 SIRIUS MCU Motor Starter

MPN3RK4320-3KQ51-0BA3

Siemens SIRIUS MCU motor starter, 3RK4320-3KQ51-0BA3, direct starter for AS-Interface, 5 A rated at 400 V AC-3, Class 10, IP54, with brake output and 2 digital inputs.

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

Specifications

3RK4320-3KQ51-0BA3 — Identification
ParameterValue
Product designationmotor starter MCU for AS-Interface
Main circuit poles3
BrandSIRIUS
Product design / constructiondirect starter
Reference designation (IEC 81346-2)Q
3RK4320-3KQ51-0BA3 — Protection & Tripping
ParameterValue
Trip classCLASS 10
Overload release setting range (current)3.5 ... 5 A
Duty / utilization type (IEC 60947-6-2)1
3RK4320-3KQ51-0BA3 — Contacts & Control
ParameterValue
Switching contact typeelectromechanical
3RK4320-3KQ51-0BA3 — Communication
ParameterValue
AS-Interface protocol supportYes
3RK4320-3KQ51-0BA3 — 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
Width245 mm
Height215 mm
Depth205 mm

Product details

What the 5 A AC-3 rating means for your motor load

AC-3 is the standard motor-switching category for squirrel-cage induction motors: starting, stopping, and plugging during normal operation. The 5 A AC-3 rating means this unit handles a motor full-load current up to that value without exceeding its thermal capacity.

AS-Interface integration and I/O

This starter communicates natively on AS-Interface (the protocol is supported, no PROFIBUS or PROFINET on board). It carries 2 digital inputs for local sensors or pushbuttons and includes a motor brake output (24 V DC control supply, 20.4–26.4 V DC range). The brake output handles a 400 V AC brake coil — common on vertical-axis conveyor drives or hoists where the brake must engage when power drops. The control supply is DC, so the unit expects a 24 V DC bus from the AS-Interface power supply or an auxiliary source.

Rated IP54, the enclosure tolerates dust and splashing water — suitable for panel-mount in industrial environments where washdown is occasional, not continuous. Dimensions: 245 mm wide, 205 mm deep, 215 mm high.

Frequently asked questions

What is the AS-Interface protocol support on this motor starter?

The AS-Interface protocol is supported. PROFIBUS DP and PROFINET are not supported on this variant.

Where can I buy the 3RK4320-3KQ51-0BA3?

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

MPN
3RK4320-3KQ51-0BA3