Our two prior posts show how to build very high voltage power supplies using flybacks from old color TVs. The advantage of the method we use is that any flyback can be driven, regardless of how its primary is wired. This is because we wind our own primary using litz wire.
The term litz wire is derived from the German word litzendraht meaning woven wire. This wire is constructed of individual film-insulated wires bunched or braided together in a uniform pattern. The multistrand configuration minimizes the power losses otherwise encountered in a solid conductor due to the skin effect or tendency of radio-frequency current to be concentrated at the surface of a conductor. A good supplier of litz wire is WireTronic. You can download a free Windows utility from their Web site that will give you dimensional data for a wide range of wire sizes, insulation specifications, current-handling capacities, resistance calculation, break strength calculation, and ordering information.
If you can’t find a flyback from an old TV, you may want to consider new units sold by Information Unlimited. Our favorite is their FLYPVM+ model that produces up to 40 KV peak at 10 mA. It features a large ferrite core measuring 3 ¾ x 3 ½ x 5/8” and has an operating frequency range of 15 kHz to 60 kHz.