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 and brush wear of a 20 HP Dynamo Commutator.
| Identifier | ExFiles\Box 50\5\ Scan279 | |
| Date | 11th January 1924 | |
| X4333 To EFC. {E. Fowler Clarke - Electrical Engineer} BY {R.W. Bailey - Chief Engineer} /RDS/ML11.1.24. X.4333 - 20 H.P. DYNAMO COMMUTATOR. Referring to your - EFC {E. Fowler Clarke - Electrical Engineer} 8/T9.1.24, I have looked up the Part list and detail of the Commutator Bar produced in Mr Ormerod's time and find it is Hard Drawn Copper. I was under the impression that both Hard Drawn and High Conductivity Copper had the same factor of Conductivity when warm. On looking up your report of June 27/23, the brush wear does not seem to me to be excessive, do you think the instances that we have had of excessive wearing have been due rather to burning caused by sparking rather than actual frictional wear? BY {R.W. Bailey - Chief Engineer} /RD. | ||