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).
Challenges and methods for creating sufficiently strong permanent magnets for magnetos.
| Identifier | ExFiles\Box 4\5\ 05-page049 | |
| Date | 21th September 1914 | |
| C O P Y. COPY To Na.{Mr Nadin} from R.{Sir Henry Royce} Copy to J.{Mr Johnson W.M.} Copy to Wor.{Arthur Wormald - General Works Manager} 21st September 1914. R1/B21914. Re Magnetos. With reference to magnetos, I understand your difficulty is getting the permanent magnetos sufficiently strong. One or two points that are necessary are as follows.- Assuming that you have the right steel, which I know depends largely upon the correct amount of carbon and tungsten, the permanency of the magnets depend upon the hardness, which could be compared with the Bosch by testing on the scleroscope. The amount of magnetism, i.e. the degree of magnetisation may be affected by tempering, i.e. it is quite possible that the permeability of these magnets may be increased by letting them down softer, but they may be less permanent. There is, however, a great deal of importance in getting them properly magnetised, and I know years ago that it was difficult to do this. If they were simply brought under the influence of a hugh electro magnet, which could bear upon them enormous magnetizing force, it would be much better than any coil around the magnets themselves. If this has not been tried it might be one of the ways of getting them thoroughly magnetised. The other way is to screw down to a bench a very | ||