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).
Modifications to the ballast resistance and coil winding to increase the life of platinum contact points.
| Identifier | WestWitteringFiles\O\2April1926-June1926\ Scan185 | |
| Date | 8th June 1926 | |
| Contd. -2- EFC3/T8.6.26. Increase of the size of the ballast resistance would also, in common with increasing the fineness of the primary winding of the coil, have the advantage of helping to increase the life of the platinum contact points. Nickel wire of 32, 33 and 34 SWG. is on order, our standard being 31 SWG. and a suitable one of these three will be chosen for making up the double value ballast resistance on the porcelain carrier as at present, it being hoped that the wire necessary will not turn out to be unreasonably fine for the purpose. There will be allowed as margin the fact that the system must be able to run the car without misfiring in all conditions and one additional cell in the supply circuit in opposition to the main battery, which battery must, for the time being, be not on charge. It is. intended to arrange the ignition in this manner on the next 20 HP. chassis for the 10,000 mile test. EFC. | ||