摘要 |
In the production of electrically insulated coils which make up insulating layers, insulating material is wound around an electric conductor to form an insulating substrate, then impregnating varnish consisting of thermosetting resin is applied to the insulating substrate and hardened. In this electrically insulated coil production method, the impregnating varnish is made up of acid anhydride setting epoxy resin elements that include latent accelerators. These accelerators take more than 30 days to increase their initial viscosity by three times during storage at 25 degrees centigrade. After the insulating substrate is impregnated with the varnish, the substrate is heated at a temperature which will cause the impregnating varnish on the surface of the insulating substrate to lose its fluidity in under 30 minutes in order to preset the varnish. Next, the varnish is set at a heat at least 10 degrees centigrade lower than the presetting temperature and thereby, electrically insulated coils with high reliability are obtained.
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