| 摘要 |
PURPOSE:To prevent a partial discharge between a core and a case, by a method wherein on the whole inside surface of an insulating case of a transformer, which is composed in such a manner that an outer circumference of a core is covered with the insulating case and coils are wound around the case and the whole is molded in one body, a conductive layer which contains carbon powder or silver powder is formed in such a manner that it dose not form a one-turn circuit by providing a slit. CONSTITUTION:A core 11 is composed by winding silicone steel plate, is covered with an insulating case 13 holding an air gap layer 12 between them, a secondary coil 16 is wound around the case 13, a primary coil 17 is wound crossing the seondaly coil 16 and the whole is housed in a mold. Then primary terminals 17a attached to the coil 17, secondary terminals 16a attached to the coil 16 and a bottom plate 18 provided with boss projections 18a are fixed inside the mold and resin such as epoxy is poured and hardened so that a transformer 20 is composed. In above configuration, a conductive layer 15 made of a paint which contains carbon powder or silver powder is formed on the inner circumference of the case 13 and the some portions of the layer 15 have contact with the core 11 without forming a one-turn circuit by providing a slit to the primary. |
