Metallized film capacitors are widely used in various types of products, for example, ballasts for fluorescent and high intensity discharge lamps, motors, etc. It is always an object to manufacture such capacitors as inexpensively as possible. To accomplish this, would include any one or more of the reduction of parts and assembly steps and the reduction of rejects of the manufactured parts. All of these serve to decrease the final manufacturing cost.
An existing arrangement for manufacturing a metallized film capacitor includes winding the film capacitor section on a bobbin in the usual roll and providing a plastic insulating wrap around the film roll. Thereafter, a bottom end cup of Kraft paper or a plastic insulator is placed within the capacitor metal outer can, and a plastic terminal insulator and a liner piece is provided for the can cover. A tab is provided to connect an electrode on each end of the capacitor section to a respective terminal on the can cover. The capacitor film section is wrapped in the plastic insulator wrap in such a fashion that the electrodes and their respective tabs are insulated from each other. The wrapped capacitor section is placed within a tube of paper or cardboard to insulate the tab from the can. The cover liner section insulates the tabs at the points of connection to the terminals.
While such arrangement is adequate, it requires substantial time and effort to assemble, relatively speaking, and is prone to assembly difficulties and errors. Also, the connecting tab from the bottom of the capacitor section must be sandwiched between the plastic wrapper and the capacitor section cardboard insulating tube with a great deal of care so that it will not tear and/or short out against the foil on the side of the capacitor section. Also, the uninsulated end of tab from the top capacitor section electrode must be folded with great care and properly insulated before its connection to the electrode on the can cover.
USPTO Backgrounds
USPTO Backgrounds