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).
Goshawk II battery ignition system and its ballast resistance design.
| Identifier | ExFiles\Box 54\5\ Scan158 | |
| Date | 19th July 1921 | |
| R.R. (10M T) A.H. 726. 10-12-20. G. {Mr Griffiths - Chief Accountant / Mr Gnapp} 2947 X3485 To EFC. {E. Fowler Clarke - Electrical Engineer} from R. {Sir Henry Royce} c. to Hs. {Lord Ernest Hives - Chair} R1/G19.7.21. X.3485 - RE GOSHAWK II BATTERY IGNITION X.3716. The ballast resistance carrier design sent through has an equal capacity to that on the Bosch ignition which is at present running on 4 EX. We do not know what ohms this is or what class of resistance wire, but as the ignition is running with tungsten points, we ought to be able to get comparatively the same working conditions with our arrangement. It should be remembered that the ballast resistance being low, ought to make the ignition more effective owing to the increase in the surging current, which seems to be checked by this resistance. We do not know whether it would do in a finer gauge or some other material. Originally this ballast resistance was made of a metal with a high temperature coefficient. It would be as well to know what the Bosch Company have found good for this purpose, and what the Delco use on the American cars which we have. The temperature coefficient would be a good guide as to the variety of metal which is used, and the resistance could easily be obtained. Most of these ignitions are perfectly effective at slow speeds, with the battery down to about half the volts. This seems necessary, because the ignition has to go on when the starter is taking its full current. R. {Sir Henry Royce} | ||