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).
Battery ignition contact points, comparing the performance of platinum and tungsten with periodic current reversal.
| Identifier | ExFiles\Box 35\6\ scan 234 | |
| Date | 19th January 1927 | |
| To R.{Sir Henry Royce} from EFC. c. to HJ. Ea. c. to Ry. EP.{G. Eric Platford - Chief Quality Engineer} Wor.{Arthur Wormald - General Works Manager} c. to Cy. FN. Emp/WRC. X2894 EPCL/T19.1.27. BATTERY IGNITION CONTACT POINTS. X4652 Two further results in connection with our report EPCL/T24.12.26 are now available. They are No.15 on Page 3 of the details, viz. periodic reversal of current, but otherwise standard conditions, the latter implying previous standard coil, i.e. not finer primary, and present standard ballast resistance and condenser. We have the results both for platinum and tungsten. No actual failure to spark occurred in either case, except that there was a slight tendency to misfire in the case of the tungsten points, latterly when running reversed from standard. Platinum. In this case the condition of the points is a good deal better than previously, the periodic reversal of current having progressively counteracted the cumulative formation of pip and cavity, the final result being that there is a slight pip and cavity on both the lever and the screw point. Otherwise the condition of the points is clean and practically no loss of platinum has occurred. Tungsten. In this case the gain due to periodic reversal of current does not seem to be so marked. Though little loss of material has actually taken place, and no appreciable pip and cavity have been formed, there is still bad oxidation Contd. | ||