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).
Testing of new insulating papers from a British source for use in ignition coils and condensers.
| Identifier | ExFiles\Box 165\5\ img008 | |
| Date | 9th May 1928 | |
| To Roy.{Sir Henry Royce} from EFC. c. Ry. X.7701 EFC3/T9.5.28. X 7701 INSULATING PAPERS FOR IGNITION COILS & CONDENSERS. Sample papers have been submitted to us by ROY.{Sir Henry Royce}, obtained from a British source, viz.Messrs. Symons & Co., one of these, quality M43M being varnished paper, and the other one a grade of waxed paper. It was proposed that these should take the place of the present standard grade of varnished paper which comes from America. We have made high pressure D.C. tests of these papers at various temperatures up to 100° and 150°C, and attached please find copy of my assistant's report PD.24 giving the results of these tests. From this it will be seen that to all appearances the Symons paper shows up equally good or even better than our present standard, but we are of the opinion that the most these tests show is that the Symons paper is worth prolonged experiment on coils and condensers and not that it can be put into use immediately. We suggest, therefore, that Ry. instructs the experimental production of say three otherwise standard ignition coils and two condensers made up with the varnished paper in each case. We have a number of coil parts which can be utilised in the making up of these coils. We consider the waxed paper might be subsequently tried in the event only of some failure arising on the suggested tests on the varnished paper. The insulation between the secondary layers of the present standard coil is 3 x .00075 of standard varnished paper, and appears to be more like .00100. The Symons paper is definitely .00075". EFC | ||