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).
Technical memo on American battery ignition systems, discussing power consumption, reliability versus magnetos, and construction materials.
| Identifier | ExFiles\Box 54\4\ Scan055 | |
| Date | 18th April 1924 | |
| X4654 To EFC. {E. Fowler Clarke - Electrical Engineer} } from R. {Sir Henry Royce} E. {Mr Elliott - Chief Engineer} } c. OJ. Rs {Sir Henry Royce's Secretary} c. Hs. {Lord Ernest Hives - Chair} Da. {Bernard Day - Chassis Design} By. {R.W. Bailey - Chief Engineer} R2/M3.4.24. BATTERY IGNITION. X.3199. X.981. X.4654. Mr. Olley tells me "that American battery ignitions take 1¼ amps. @ 6 volts = 7½ watts Bosch U.S.A." Therefore our running current ought to be .625 amps 12 volt, with a possibility of running with from 6 to 8 volts at moderate speeds to get an engine started with a low battery. RR. U.S.A. have decided that magnetos are not so reliable because machines are not now made for high class cars. Tungsten points are better and more reliable and a fraction of the cost compared with platinum; throw away these when damaged. Coils are now made by several U.S.A. constructors with nearly closed in circuits with some advantages either in improved ignition or less current, or less fine copper wire. [Diagram of a laminated iron core] Laminated sheet iron, say Stalloy. .08 gap about The ignition only taking a small amount of electrical energy might alter my opinion about double ignition. American fibre known as 'bone' (hardness), grey (colour) is the material they have found best for contact maker blocks. R. {Sir Henry Royce} | ||