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).
Letter discussing design considerations for small poles, DC brush holders, and AC brush holders.
| Identifier | ExFiles\Box 180\M6\ img008 | |
| Date | 24th November 1929 | |
| (1) West WitteringHenry Royce's home town Nov 24/29 Sunday Dear Mr "Bentley" Re small 2 poles for 400T The difficulty was thought to be due to the whittling throughness of the castings so that a wrongful tubular yoke. If this is not so there is no need of a short, thick ring. My object of making the ring short & thick was to enable the [illegible] I intended to drill into the thick yoke not try shields unless there are thoughts less expensive or forks. Re. D.C. brush holders I rather thought you had given up bakelite and rubber insulation for brush holder, because of the high voltage & the presence of copper & carbon dust. Re. AC brush holder I think your square spindle is not big enough to get hold of firmly & to be rigid. It is much more rigid if one could only win by forcing into a drop forging. TTO | ||