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).
Material composition and pressure for starter motor brushes.
| Identifier | WestWitteringFiles\D\October1919\ Scan3 | |
| Date | 1st October 1919 | |
| WN To EFC. from R.{Sir Henry Royce} Copy to CJ. " " " BN.{W.O. Bentley / Mr Barrington} " " " OY. X.2656 (Struck through) X 3082 [Stamp: RECEIVED 9 OCT 1919] [Stamp: ORIGINAL] R2/G6/10/19. (4 RE BRUSHES FOR STARTER MOTOR. It will be remembered that from observations of the condition of the commutator and from the fact that we have an ample brush area, owing to the use of four brushes on our starter motor, I suggested the use of a brush containing more carbon and less copper. This seems to be borne out by the recommendations of the Morganite Company. I agree with the use of Morganite brushes of the type of CN{Mr Chamberain}3, having approximately 80% of copper and the rest graphite, and a pressure of approximately 6 lbs per square inch, or 3 lbs per brush should be aimed for, [illegible signature] R.{Sir Henry Royce} | ||