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).
Dynamo commutator and brush performance, focusing on blackening and bedding issues.
| Identifier | ExFiles\Box 50\5\ Scan208 | |
| Date | 25th July 1923 | |
| Contd. -3- and brushes properly bedded suffers any appreciable alteration of output in use. It is further our experience that commutation in these circumstances, even with the present brush gear and brushes, is quite fair. We do not say that the commutator does not suffer any blackening (some go fairly black, others do not appear to blacken at all), but what blackening does take place appears to be uniformly distributed over the commutator segments and we have had hardly more than a suggestion of the effect of partial blackening or burning half way across the segments. We have now on our experimental cars no less than nine 20 H.P. dynamos, and the remarks made above are derived from examination of the brushes and commutators and output of these machines. All these dynamos appear to be running, as far as results (apart from appearance) are concerned, perfectly satisfactorily. It will be admitted as natural, therefore, for it to appear to us that what is required is more careful attention to bedding. On taking up the matter, however, with the Production Dept. and being assured that the bedding is done with all possible care, we can only say that the poor performance of machines on production compared with experimental machines is still rather a mystery. As regard bedding from the point of view of overcoming variations in the output, the bedding of the negative and control brushes is the more important. The bedding of | ||