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).
Extract from a communication regarding the rapid wear of a dynamo's third brush.
| Identifier | ExFiles\Box 47\4\ Scan212 | |
| Date | 1st January 1925 guessed | |
| E X T R A C T. "One of the third brushes is required for use, the others are for spares. I should like to point out that this is the third time during 13,000 miles that the third brush has worn away. You fitted the last one during July, and it has done only 4,000 miles, being completely worn out. The Dynamo otherwise is perfect and gives no other trouble." | ||