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).
'Liberty' battery ignition system and potential improvements for a coil design.
| Identifier | ExFiles\Box 37\1\ scan 029 | |
| Date | 4th May 1918 | |
| To EFC. from R.{Sir Henry Royce} c. to CJ. c. to CY. X.3199. 4th May. 1918. R8/G4.5.18. X.3296 RE "LIBERTY" BATTERY IGNITION. X.3199. X.1819 X3716 X.3081. X.3292. X.3173 X3129 Thanks you for your notes on the "Liberty" battery Ignition, most of which we understand except the low tension contact breaker; this, from your description, appears to be rather a clever arrangement, but a decided extra complication which we should have thought would only have been introduced after failure to get a satisfactory result by simpler means. Regarding the amperes on short circuit, the eight amperes mentioned appears very high, and we should think that the primary contacts would require to be double, as suggested, for such a high current. On second consideration, however, it does not seem much in excess of the three amperes adopted by us when the difference of voltage is considered. When we read the description of the test of our own coil, it seemed to me that we could improve the working when considering the still higher speed of ignition, by having a greater percentage of the resistance in thr ballast resistance, so that the second coil that you are considering, I should suggest that we had a smaller number of primary turns, and a larger ballast resistance that would check the current on short circuit a greater amount, and be content with a rather larger current consumption at higher speeds. I think it will be found that we can choose between a large current running, and small short-circuit current. (CONT'D) | ||