Patent attributes
A choke device for a frequency converter, comprising three windings composed of conductors wound around three substantially parallel axes (A, B, C), respectively, the windings being 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 (A, B, C), the winding axes are located at the vertices of the triangle, the choke device further comprising an envelope (1) surrounding the windings, a first end (3A) thereof being provided with at least one opening (20) for receiving cooling medium to the inside of the envelope, and a second end (3B) being provided with at least one opening for discharging the cooling medium from the envelope, and an envelope axis (D) between said first and second ends being substantially parallel with the winding axes (A, B, C).