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 comparing performance and wear of Z brushes on a Goshawk Dynamo.
| Identifier | ExFiles\Box 50\5\ Scan263 | |
| Date | 13th November 1923 | |
| COPY. EFC. {E. Fowler Clarke - Electrical Engineer} SB. {Mr Bull/Mr Bannister} 92. 13th Nov. 1923. MODIFIED COMMUTATION OF GOSHAWK DYNAMO. A set of Z brushes has been run for the equivalent of 2500 miles continuously, and for 50 hours intermittently, first in the old standard condition and then with the commutator und-ercut by the new process and the tops of the brushes bevelled in the up-to-date way; the object being to compare performance and wear. In the first run, sparking was moderate and the positive brush became irregularly polished. The megative and control brushes were polished in the usual way. The commutator was slightly burnt at the trailing edges of the segments and was somewhat irregular in its discolouration. The brush wearr was :- Positive .022", Negative .023" Control .0195" In the second run, sparking seemed little changed, but the positive brush acquired a better polish than before, while the commutator was not burnt at the edges of the segments, and was of a uniform light brown discolouration. The wear in this case was:- Positive .0075", Negative .0215" Control .0235" In both tests, the springs were of standard pressure. F.J. Allen. | ||