From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Temperature leakage tests conducted on various types of insulating papers.
| Identifier | ExFiles\Box 24\2\ Scan282 | |
| Date | 8th May 1928 | |
| EFC. PD24. May 8th 1928. TEMPERATURE LEAKAGE TESTS ON INSULATING PAPERS. Tests have been made on some specimens of insulating papers; making a comparison between them with respect to leakage at various temperatures. The papers used were :- (1) Standard grade of varnished paper (American), at present used in both ignition coil and theecondenser. (2) A grade of varnished paper (Quality M/43M) obtained from H.D. Symons & Co., and proposed for use in the ignition coil. (3) A grade of waxed paper also obtained from Symons. In each case a number of discs cut from the paper, sufficient to give a total thickness of .100", were placed between two electrodes and the whole put into the oven. Pressures ranging from 9,500 volts down to 2,000 volts, were applied across the electrodes and the leakage currents measured in the usual manner. The temperature in the oven was varied from atmospheric up to 100°C. in the case of the standard and waxed papers, and up to 150°C in the case of the Symons varnished paper, as this shewed no signs of leaking. The results are as follows :- Conductance (Micro-mhos.) Specimen. 20°C. 30°C. 40°C. 50°C. 60°C. 70°C. 80°C. 90°C. 100°C Standard (Varnish) o o .001 .003 .013 .031 .061 .191 .201 Symons (Varnish) o o o o o o o o o Symons (Wax). o o o o o .002 .004 .006 .017 As previously mentioned, the Symons sample of varnished paper shewed no signs of leaking even at 150°C and, in spite of the higher temperature, it appeared to be the least affected. Contd. | ||