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).
Analysis of test results comparing the performance of different dynamo brushes and commutators.
| Identifier | WestWitteringFiles\L\Jan1924-March1924\ Scan150 | |
| Date | 7th March 1924 | |
| Contd. -3- EFC1/T7.3.24. Analysis of the detailed results of the various reports will show that the best all round result has certainly been obtained on dynamo D, the conditions of which are representative of present standard production, namely, brushes of Z Le Carbone material with bevelled tops and specially undercut commutator. Next comes dynamo 470 with ECO Morganite brushes, also bevelled and working on an undercut commutator. The condition of dynamo R3 taken from 7C11 does not appear to be so good. This is put down to the fact of the commutator not being undercut according to our latest standard practice. It may be remembered that it has been previously reported that EG2 and ECO Morganite brushes are considered to be about equally good (if anything the EG2 a little better) when working under similar conditions, i.e. both working on undercut commutator, and as a result of this we have recommended EGB Morganite brushes as a stand-by alternative in case of failure of supply of Z Le Carbone. We think they are very good for the purpose but just very slightly inferior to the Z. It perhaps should be remarked that our reference to a 'non-undercut commutator' means one that has not been specially undercut by the new process which is at present -standard, which absolutely ensured the removal of every trace of mica. In the early stages, although the slots Contd. | ||