Process for manufacture of high voltage transformers and the like
US4333900A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 1, 1979 |
| Grant date | Jun 8, 1982 |
| Priority date | — |
| Expiry date | Oct 1, 1999 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01F41/005
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A process for making an encapsulated electrical insulation system such as a transformer which includes a porous fiber material filling. The system is vacuum baked at a temperature range of 100.degree. C. to 155.degree. C. for at least four hours, and is then vacuum impregnated with a mixture of a modified bisphenol A epoxy resin hardener comprising various acid anhydrides plus promoters. Pressure is then applied to the system of 1,000 psi. of nitrogen at 80.degree. C. for 2 to 12 hours. Thereafter, the temperature is increased to 110.degree. C. for 2 to 12 hours. The system is then cured at 135.degree. C. for approximately 12 to 24 hours. To minimize corona, shields are placed in selected portions of the transformer, the shields having edges formed into radii ends to avoid points at which corona would normally tend to concentrate. Also, the transformer is wound using ultra-clean components to obtain a transformer package that is free from impurities prior to impregnation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.