Patent ID: 7088027

Claim:
A rotating asynchronous converter for connection of AC networks with equal or different frequencies, wherein the converter comprises a first stator connected to a first AC network with a first frequency f 1 , and a second stator connected to a second AC network with a second frequency f 2 , wherein the converter comprises a rotor which rotates in dependence of the first and second frequencies f 1 , f 2 , and wherein at least one of said stators comprises at least one winding, including at least one current-carrying conductor, and an insulating system including a first semiconducting layer surrounding the conductor and being in contact therewith; a solid insulation layer surrounding the first layer; a second semiconductor layer surrounding the insulating layer; said insulating system forming an equipotential surface surrounding the conductor, and wherein said first and second semiconducting layers and the solid insulation layer have substantially equal thermal expansion coefficients.