What is the 3RK4320-3HQ51-0BA3?
It's a direct starter with electromechanical switching contacts, rated for 3.2 A at AC-3 duty on a 400 V supply, and provides motor protection via a bimetal trip element set to CLASS 10. The unit operates on a DC control supply voltage of 20.4 to 26.4 V and draws its main power from a 340 to 440 V AC line at 50 or 60 Hz. The CLASS 10 trip class ensures the bimetal overload relay disconnects the motor within 10 seconds under locked-rotor conditions, protecting windings from thermal damage during a stall. This is the spec that governs real-world motor protection, not the higher AC-1 resistive rating.
Where is it used?
This motor starter mounts on a vertical surface with +/-180° rotation possible, and can be tilted forward and backward by +/-22.5°. The IP54 ingress protection means it's sealed against dust ingress and splashing water — suitable for installation in control cabinets on factory floors where occasional washdown or airborne particulates are present. With 2 digital inputs and bus communication via AS-Interface, it integrates into a distributed I/O architecture. The 205 mm depth, 245 mm width, and 215 mm height dimensions dictate the enclosure cutout and clearance for cable glands.