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).
Failures and experiments related to ignition coil secondary windings.
| Identifier | ExFiles\Box 69\2\ scan0011 | |
| Date | 22th May 1930 | |
| X8712. By from EFC. c. Sft{Mr Swift}/Mr.Brock. EFCl/AD22.5.30. X.8712. IGNITION COIL SECONDARY LAYER TO LAYER X.6014. X.6014.44. FAILURES AND IN PARTICULAR IGNITION COIL WITH SECONDARY WINDING IN TWO SECTIONS In any electrical system abnormally high voltages can only, in the nature of things, be associated with abnormally high frequencies. Therefore any means whereby surge frequencies in apparatus can be lowered will automatically result in reducing disruptive or breakdown voltages. Fundamentally, the two means of reducing frequencies of parasitic oscillation are increase either in inductance or capacity associated with these. We have one or two experiments in hand on suppression of abnormal layer voltages, one of these being the introduction of an insulated layer of tinfoil between the first and second layer of the secondary. An otherwise standard coil so arranged has passed our schedule test completely but will be subject to breakdown by intentional intensive working in order to see whether the weakness has been removed either completely or to another portion of the winding. It will be agreed that the fundamental idea should be the removal or suppression of the high voltages rather than attempting to insulate against them. We have now apparatus by which we are able to measure the peak voltages between points of the secondary winding in various experimental coils in which suitable secondary tappings are brought out, and some interesting results are being obtained. One particular experimental coil we would like to try, is one in which the secondary winding is made in two identical sections of half the normal width but placed side by side, their inside ends being connected to constitute the middle of the winding. As in other cases of experimental coils, it would be better to provide this coil with a third terminal corresponding to the beginning of the secondary winding, which beginning is the outside of one of the sections. We should be pleased if you would arrange for such a coil to be instructed for experiment. | ||