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).
Tests on various insulating papers to compare their performance under heat and electrical stress.
| Identifier | ExFiles\Box 165\5\ img012 | |
| Date | 31th May 1928 | |
| X.7701 EFC. PB.26. May 31st. 1928. TESTS ON INSULATING PAPERS. A number of tests have been carried out on insulating papers, using samples of the standard (American) varnished paper, and varnished and waxed papers (British) from Symons. The American paper is at present used in both the ignition coil and the condenser. The object of these tests was to compare the three papers with respect to :- (1) Variation in the resistance of the material with increase in temperature. (2) The effect on the resistance of the material, of repeated heatings, and the permanency of such an effect. (3) Dielectric strength. (4) The effect on the dielectric strength of heating. An additional test was made in the case of the standard paper, as the result of it having been observed that a coil which had been left in circuit for about two hours and consequently raised to a temperature of 130oC, failed to give normal sparking. (1) A sample of each paper was tested at various temperatures, from atmospheric up to 100oC, as described in PD.24 8.5.28, when the following results were obtained :- Paper. Commenced to conduct Conductance at 100oC. American varnished. .001 micromhos at 40oC. .201 micromhos Symons varnished. ---- Symons waxed. .002 micromhos at 70oC. .017 micromhos. As there was no leakage with the Symons varnished paper at 100oC it was taken up to 150oC, but still shewed no signs of leaking. Symons varnished paper is decidedly the best in this respect, the waxed paper being next. Contd. | ||