Winding form for high voltage transformer

摘要

An automotive ignition system transformer including a ferromagnetic core, a primary coil and a secondary coil. The secondary windings are wrapped on a tubular insulating winding form or bobbin with annular radial portions defining a plurality of annular coil chambers including a plurality of central chambers and at least one end chamber. The end chamber defines a spiral land that proceeds both axially toward the respective end and radially outward for three or more complete turns. The respective end turns of the coil are wrapped one turn of coil on each turn of the spiral land so that successive turns of the end portions of the secondary coil are both axially and radially spaced from one another sufficiently to minimize arcing.