| 摘要 |
PURPOSE:To decrease voids in thermosetting resin after hardening and improve the dielectric breakdown voltage of a coil for an electric machine by a method wherein the resin is heated and hardened under a pressure reduction condition while gas sucked under the pressure reduction is purified and exhausted into the atmospheric air. CONSTITUTION:Pressure in a vacuum bell jar 1 is lowered by means of a vacuum pump 3 since just after thermohardening resin such as epoxy is impregnated to a conductor of a coil 2 for an electric machine and an insulating layer wound on the circumference. The resin is heated by means of an infrared heater 4 at the same time. Gas generated at that time is forcedly exhausted into the atmospheric air through a gas line filter 5. Pressure reduction is stopped just before the resin begins to harden. Thus, voids in the resin after hardening are decreased, and the dielectric breakdown voltage of the coil for the electric machine can be improved. |
