Patent ID: 7969264
Filing Date: 2011-06-28
Classification: H01F

Abstract:
1. A choke device for a frequency converter, comprising: three windings composed of conductors wound around three substantially parallel axes, respectively, which windings are located triangularly with respect to each other in such a manner that, when the choke device is viewed in the longitudinal direction of said winding axes, the winding axes are located at the vertices of the triangle; and an envelope surrounding the windings, a first end thereof being provided with at least one opening for receiving cooling medium to the inside of the envelope, and a second end being provided with at least one opening for discharging the cooling medium from the envelope, and the envelope comprising a mid portion conforming to winding surfaces oriented outwards from the triangular array of the windings in such a manner that a gap remains between the mid portion of the envelope and the outwardly oriented surfaces of the windings, the gap enabling the flow of said cooling medium between the mid portion of the envelope and the windings through the windings, and an envelope axis between said first and second ends being substantially parallel with the winding axes.