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).
Ignition coil development, discussing insulation, testing, and comparisons with American coils.
| Identifier | ExFiles\Box 164\5\ img028 | |
| Date | 28th January 1931 | |
| EFC/AD28.1.31 contd. -5- With regard to the provision on the coil of some limit of voltage in the form of a safety gap, this is already intended to be provided in the distributor which is at no great distance from the coil itself and might reasonably, it would be supposed, act as effectively as such a safety gap provided on the coil itself. In regard again to the impregnation of secondary windings, we have also made the experiment of thoroughly impregnating these with paraffin wax but without noticing any particular advantageous result. We have advocated the use of wax of higher melting point owing to the use of the ignition coil in a rather hot position. It may also be remembered that we have advocated again removing the coil from its present hot position to the wheelcase position as we once previously did for the sake of keeping the coil cool. It would appear that if we wish to attempt to produce bigger voltages than are utilised in the case of other makes of coils, the only solution would be some method of sectionalising the secondary windings such as becomes essential in coils for higher voltages produced for other classes of work. We have already tried a coil with the secondary in two sections and after 200 hours intensive testing it is still O.K. Tests on this coil are still in progress. Mr. Brock has been and is working in conjunction with my assistant Mr. West and myself to obtain the very best form of insulation. With regard to American coils used in this country, our own experience has been similar in that not only did they stand up no better than our own coils on the various tests we could make, but that in this country, at any rate, they are to the same degree liable to failure. We are experimenting with outside primary coils and will certainly test and examine the coils from U.S.A. brought over by Hs.{Lord Ernest Hives - Chair} Experience of Remy coils on Chrysler and, we believe, on Mr. Elliott's Vauxhall has been that no failure has occurred in respect of misfires etc. over a long mileage. Further, it is understood that Hs.{Lord Ernest Hives - Chair} has tried the Dejon coil on the 20/25 with satisfactory results i.e. no misfires. EFC. | ||