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).
Testing and selection of different quality brushes from the Morganite Company for a starter motor.
| Identifier | ExFiles\Box 35\1\ scan 020 | |
| Date | 25th September 1919 | |
| To R.{Sir Henry Royce} from EFC. c. to W.J. c. to Hw. c. to Em. c. to Da.{Bernard Day - Chassis Design} c. to Ey. c. to El. X. 2656 EFCB/T25.9.19. X. 2656 - BRUSHES FOR STARTER MOTOR In accordance with E4/G5919, we have taken up further the question of brushes and brush pressure for the starter motor. We have written to the Morganite Company and attach copy of this letter which will explain our position and render unnecessary going over the same ground in this note. We received an answer to this letter, copy of which is also attached and yesterday we received, as therein arranged, a visit from Mr. H.T. Sparkes of this Company. As stated, he brought with him one dozen brushes to drawing G.3901, in C.M.2 quality and another dozen brushes of C.M.3 quality. Both these qualities of brush will be tried out experimentally in due course. Mr. Sparkes stated that the C.M. quality contained about 95% copper, that the C.M. 1 contained some tin, and was definitely not suitable for our present purposes, that the C.M.3 contained 80% of copper, the rest being graphite, and that the C.M.2 was intermediate between the C.M. and the C.M.3 qualities in this respect. Mr. Sparkes was inclined to recommend C.M.3 for our purpose, and we are sending down a sample of this quality of brush with Mr. Royce's copy of this note. He recommended, as will be seen from his letter, still further increasing our brush pressure. to, say, 6 lbs/sq.", as we have suggested in ours. Contd. | ||