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 system energy consumption and performance testing of 'Eska' tungsten points.
| Identifier | WestWitteringFiles\L\2April1924-June1924\ Scan145 | |
| Date | 29th April 1924 | |
| EFC3/T29.4.24. -4- Contd. (1) The probability is that this consumption is given for relatively high engine and contact breaker speed when the consumption will be low. At the lower engine engine speeds, the consumption will no doubt be a good deal more. (2) Because it is necessary for us to get efficient operation at relatively very low speeds, it is necessary for us to have a good deal larger proportion of ballast resistance to primary coil resistance than the U.S.A. ignitions, and this means that we are not really using very much more energy on the coil as would at first sight appear. (3) Owing to the larger proportion of ballast resistance, we probably get a much smaller consumption relatively at the slow speeds than these U.S.A. ignitions. Taking all things into consideration, I should very much doubt whether the watt-hours utilised in operating our ignition are really any more than those used in operating one of these American battery ignitions, and it is very probable that in cases where the switch is inadvertently left on, our loss of battery energy would be definitely less. With regard to tungsten points, though we have not formerly had much success with these, the last batch we obtained, which are called "Eska" tungsten points, and have been fitted to our points and levers by Messrs. Melin & Co., have been the most satisfactory. One pair of these have done to date 9,000 miles on 7GII and another pair 2000 miles on 3GII with reasonable satisfaction, the only attention to the points being that instructed in the Instruction Book. Another pair have now been fitted to 6GII and it is hoped that it may be demonstrated by this batch that the use of Contd. | ||