Square D Company

Other

Greg Lawrence

James T Tucker

Michael W Knight

Gregory Link

A method for high speed spin winding a coil on a continuous lamination core. A two piece or hinged bobbin having two flanges is placed around a leg of the transformer core and snapped together. Both flanges include an outwardly facing surface which defines a concentric groove. One flange includes passages for receiving printed circuit board terminating pins which are installed prior to winding the coil. The other flange has a circumferential gear located in its outwardly facing surface. The core with bobbin and terminating pins installed is placed into a spin winding fixture. A bobbin bearing having a bearing surface including a circumferential ridge is placed adjacent the outwardly facing surfaces of the two flanges such that the circumferential ridges are partially received within the concentric grooves of the outwardly facing surfaces of the two flanges. A wire feeder terminates the leading end of the coil wire on one of the terminating pins. A drive gear engages the circumferential gear on the flange and rotates the bobbin at high speed drawing wire from the wire feeder. The wire feeder moves back and forth between the two flanges to uniformly wind the coil wire on the bobbin. The wire feeder terminates the trailing end of the coil wire on the other terminating pin and then cut the wire off. The terminating pins are pressed further into the flange until the desired length for printed circuit board connection extends outwardly from the opposite side of the flange.

Method for high speed spin winding of a coil about a continuous

A method of assembling a three phase current transformer for printed circuit board installation. Three current transformers, each having a spin wound coil positioned about one leg of an unassembled continuous lamination core, are placed side-by-side in a transformer carrier such that two parallel core legs of the center transformer overlap the adjacent core legs of the two outside transformers and further such that printed circuit board terminal pins attached to the coils pass through stand-off sleeves formed from the transformer carrier. Rivets are placed through holes in the laminations of the overlapped core legs and in the transformer carrier thereby simultaneously riveting the three transformer cores and the transformer carrier together making a three phase transformer assembly.

Method for assembling a three-phase current transformer

A bearing for maintaining a bobbin in relative position about a transformer core leg during the winding of a coil on the bobbin. The bearing is movable along the core leg such that a bearing surface of the bearing is positioned adjacent to but not touching each of two outwardly facing surfaces of two spaced apart flanges of the bobbin. The bearing surface is highly polished to reduce friction. The bearing surface preferably includes a circumferential ridge centered about the axis of the transformer core leg on which the bobbin is positioned. The outwardly facing surfaces of the two flanges each include a concentric groove shaped to complement the circumferential ridges of the bearing surfaces. When the bearing is in position the circumferential ridges are partially received within the concentric groove such that a small gap is maintained between the bearing surfaces and the outwardly facing surfaces. The bearing surface can also include ports for exhausting low pressure air into the space between the bearing surface and the outside surface of the bobbin flange. The low pressure air cools the bearing surface and acts as a cushion between the bearing and the bobbin flanges.

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Wilson, NC, United States of America

Greg Lawrence