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).
Desired qualities and issues with Goshawk dynamo brushes.
| Identifier | WestWitteringFiles\I\July1922\ Scan35 | |
| Date | 19th July 1922 | |
| R.R. 335 A (100 T) (STF 846 6-S-19) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 2460. To EFC. from R.{Sir Henry Royce} ORIGINAL RECEIVED JUL 11 1922 R1/M19.7.22. X.4333. I have received your memo. re Le Carbon's ref-erences to Goshawk dynamo brushes. I do not know the peculiarities of the 2 grades mentioned but what we are particularly desirous of using is (1) a brush which has fairly high specific resistance so as to reduce the tendency to spark, and (2) it should also be exceed-ingly good from a wearing point of view, this being particular-ly necessary owing to the high speed of the dynamo. We are not desirous of using a very efficient brush as regards loss of voltage or current carrying capacity, these being in my impression distinctly against the first con-dition. We shall of course be pleased to hear the results of the test of the wearing and sparking qualities of the EG.30 suggested by Le Carbon's as an alternative for the Z.O. I be-lieve the Z.O. is the quality recommended by me from experience with Royce Ltd. We are not anxious to venture into various other makes of brushes under the present conditions in which we are working. We are very anxious not to do pioneer work out-side our own direct business, and only that which is absolutely necessary. The brushes on the dynamo at this house grow in thickness and jam in the holders, and have to be repeatedly and regularly filed to make them free - a most mysterious and troub-lesome fault should it occur on a car. R.{Sir Henry Royce} | ||