Abstract: Disclosed is a coil including winding support means for supporting a base layer of wire including a first predetermined number of turns wound in a precision pattern about the support means. A wire tap layer is wound about the support means at an average pitch ratio substantially equal to a second predetermined number of turns for the tap layer divided into the first predetermined number of turns. A tap of wire is then taken from an end of said wire tap layer. Finally, a subsequent wire layer is wound over and in an opposite direction to the tap layer, wound at an average pitch ratio substantially equal to the first predetermined number of turns in the tap layer divided by the difference between the first predetermined number of turns and the second predetermined number of turns.The present invention is also directed to a method of winding a coil.

Abstract: The common winding of an autotransformer is formed in two sections connected electrically in parallel and one section overlying the other. One section is wound clockwise and the other is wound counterclockwise. This reduces the voltage difference between adjacent layers of the two sections, permits the use of a smaller wire, and results in cooler and more efficient operation.

Abstract: The common winding of an autotransformer is formed in two sections connected electrically in parallel and one section overlying the other. One section is wound clockwise and the other is wound counterclockwise. This reduces the voltage difference between adjacent layers of the two sections, permits the use of a smaller wire, and results in cooler and more efficient operation.