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).
Method for burnishing the contact surfaces of starter motor brushes based on a visit to Messrs. Smiths'.
| Identifier | ExFiles\Box 35\1\ scan 024 | |
| Date | 26th September 1919 | |
| X.2656 1 To By.{R.W. Bailey - Chief Engineer} from EFC. c. to BY/HBC. c. to Bn.{W.O. Bentley / Mr Barrington} EFC2/T26.9.19. <s>X.2657</s> <s>X 3082</s> RE MACHINE FOR BURNISHING CONTACT SURFACES OF STARTER MOTOR BRUSHES. During our visit to Messrs. Smiths' on Monday last, they told us they had had a certain amount of trouble with the brushes on their starter motors, but that they had overcome this by thoroughly burnishing the working surface, after grinding to correct radius, by running these on a copper cylinder of the same diameter as the commutator, loaded up to 10 times normal pressure, the burnishing being continued until the surface showed 100% efficiency. We have always noticed that brushes behave very much better on the load tests as a result of the half an hour light running, which the motor is given before being put on load. We think, therefore, this is an idea worth carrying out in connection with the production motors, as we are not, at the moment, satisfied that we are getting quite the best results obtainable with the brushes. Presumably this would be a job for the Plant Dept. to instruct, so if you think it is worth while, will you kindly instruct this Dept. to proceed with a suitable design. EFC. R.R. 235A (500 T) (S.D. 408. 25-4-17.) Bm. 2/156/13. | ||