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).
The testing of varnished insulating paper for ignition coils.
| Identifier | ExFiles\Box 61\1\ scan0142 | |
| Date | 31th October 1930 | |
| X6110. By.{R.W. Bailey - Chief Engineer} from EFC. c. By/RD. c. Sft{Mr Swift}/Mr.Brock. EFC1/AD31.10.30. X.1109 X.6018 INSULATING PAPER The sample of varnished insulating paper as used in the Lucas ignition coil and sent to us under cover of By/RDL/W27.10.30 has been duly tested and the following is my assistant's report WE.57 thereon :- "This paper is the best we have tested so far as regards breakdown volts per mil which, when tested on the H.T. transformer were found to be 2350. The previous best figure, obtained with Symon's waxed paper, was 1874 volts per mil, so that the Lucas is 25% better in this respect. The conductance test gave the following figures :- Temperature. Conductance. 20°C. O 40°C. O 60°C. O 80°C. .001 micromhos 100°C. .005 This conductance test was carried out on a .0175" thickness of paper as a .017" thickness could not easily be obtained, but this .0005" extra thickness should not affect the leakage comparisons appreciably. It will be seen that the conductance figures are also very good and although not so good as Symons varnished paper are as good as the waxed paper. We consider this paper to be the best we have tested of ignition coil insulating papers." We consider that we should obtain for confirmatory test some samples of this grade of paper of a thickness we should desire to use on our own coil. EFC. | ||