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).
Experiment report on the failure of tungsten contact breaker contacts, recommending platinum as an alternative.
| Identifier | ExFiles\Box 35\5\ scan 007 | |
| Date | 30th April 1917 | |
| R.R. 255 A (400 T) (S.C. 536 18-2-16) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 1546. To R.{Sir Henry Royce} from EH. c. to J.{Mr Johnson W.M.} c. to By.{R.W. Bailey - Chief Engineer} c. to E X. 2894 EH1/AT30.4.17. X. 2894 X. 2753. CONTACT BREAKER CONTACTS MADE IN TUNGSTEN This experiment originated from an offer made by the L.P.S. Electrical Co. (attached is a copy of their letter). As we had heard that Americans were using this material we had two contact breakers fitted with these contacts. They were run on two Watford magnetos. For the first few hours running they were quite satisfactory, after that the points of one of the contact breakers broke to pieces which caused misfiring. The magneto fitted with the second contact breaker also starter to misfire. [handwritten insertion: there did not appear anything wrong with the contact breaker] It was cured by changing the contact breaker, [handwritten insertion: except] that a whitish powder formed on the points. We are writing to the L.P.S. Electrical Co. to see if they have any explanation, but for the present we consider, that for such a vitally important part as the points of the contact breaker, platinum should be used. EH. | ||