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).
Page from a report on comparative utility tests between a magneto and a battery ignition system, discussing spark performance and leakage paths.
| Identifier | WestWitteringFiles\F\January1921\ Scan10 | |
| Date | 21th December 1920 guessed | |
| Contd. -2- EFC2/T7.1.21 (c) As (b) but both primaries are now short circuited. (d) The secondary of one coil only is connected across the gap and its primary short circuited. Thus we have four stages which are sufficient for getting comparative utility tests. The results of trials of this nature made on a standard Watford E.6 magneto and our standard battery ignition are given on the accompanying table. It will be seen that whereas the spark obtainable from the ignition coil is much longer than that from a magneto, the former is more readily reduced by providing the leakage path across the gap. The figures given for the magneto are for the advanced position, so as to represent normal working conditions. We found that for the retarded position the falling off, due to leakage paths, was not quite as great. It was attempted to make a leakage path by pencil marks on paper, but to convey any appreciable current a very heavy mark was required and the graphite was rapidly dispersed by any discharge. EFC. | ||