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).
Test report on dynamo brushes detailing issues of irregular charging, sticking, sparking, and heavy wear.
| Identifier | ExFiles\Box 60\1\ Scan133 | |
| Date | 4th April 1929 | |
| RR 238 (150 BKS.) (DB{Donald Bastow - Suspensions} 431-8-12-24) MP 306975 ROLLS-ROYCE LTD. INSTRUCTIONS. 19 To Order No. PD 41 (2) Customer's No. The results of these tests were as follows:- Dynamo L on 14 EX. These brushes were fitted 4-4-29 and travelled 11,675 miles. Twice, during the test, complaints of irregular charging were made, the trouble each time being traced to sticking of the control brushes. On removal from the car, the machine was run on the bench, when the brushes were found to be no quieter than the standard type. It was also observed that rather bad sparking was taking place at the control brushes. From an examination of the machine, this was ascertained to be due to sluggishness of the brushes in the holders and consequent bad contact with the commutator. The commutator was found to be badly blackened, although the control brushes were only a little blackened and the main brushes were clean and well polished. The brush-dust deposit did not appear to be excessive, but brush wear was found to be heavy. Signed Cont'd This Sheet must be filed on completion of the work. | ||