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).
Performance comparison of platinum and tungsten interrupter points, coils, and condensers.
| Identifier | ExFiles\Box 35\6\ scan 176 | |
| Date | 11th June 1926 | |
| 3 Ho COPY X2894 TO HS.{Lord Ernest Hives - Chair} Oy2-E-61126 June 11, 1926. Handwritten annotations: This is equivalent to your Y E F C By Hs{Lord Ernest Hives - Chair} 24 JUN 1926 x4657 x4652 x2894 (RECEIVED 28-6-26) X4278 Mr. Basil Johnson, Rolls-Royce, Ltd., London, England. (Copy for attention of Mr.F.H.Royce " " " " Works Committee " " " " Mr. Nadin) Dear Sir: Re Platinum interrupter points, coils and condensers - Section 5150 1. We find the platinum points on the battery ignition head to be inferior to tungsten in actual performance in the U.S. 2. We also have reason to believe that the type of coil with an almost continuous iron circuit is more gentle in its treatment of the interrupter points than the present English coil. 3. The English condensers appear to partially break down in the dielectric either in storage or in shipment across the Atlantic. 1. Interrupter points. a.{Mr Adams} The platinum points on 12-MC we found required bedding every 1000 miles or so. At 5000 miles we had to install a new set. These ran 600 miles and are in attached envelope marked I. b. Tungsten points were put in with an American Bosch coil, 12 volt, as shown in print A-2823 attached. These ran 1000 miles and were then inspected. The tungsten points showed practically no signs of use beyond slight discoloration round the edges. c. Because we had changed two things at once we decided to put back the English coil to make a fair test. Tungsten contacts have since run 8000 miles and are in envelope marked II. It will be seen that, though pitted, their condition after 8000 miles is comparable with the condition of the platinum after 600 miles. | ||