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).
The examination and faults found on Dynamo No. 229.
| Identifier | ExFiles\Box 47\4\ Scan189 | |
| Date | 1st July 1924 | |
| X4383 To EY. from EFC. EFC2/T1.7.24. X.4383. DYNAMO No.229 - EX 59-S.8. BEARD. Reference your EY/C9/K.11.6.24, on this dynamo being received, it was examined and the following noted:- (1) The solder had been thrown from the commutator connections. (2) There was evidence on the commutator spokes suggesting that brush arcing ( as when dynamo on open circuit) had taken place, the effect of which had been cleared away on the main commutator surface. (3) Commutator had a scratched appearance of having been partially cleaned on its working surface with emery cloth. (4) The brushes had only partially bedded surfaces, the unbedded portions being new as they had been rubbed with emery, after which an attempt was made to re-bed them. (5) The control brush was too far retarded, the retard angle being 110° in place of approximately 122° as called for on the specification. (6) On attempting to run the machine it was found only partially to excite, and this in the wrong direction. The partial excitation would be due to the faulty commutator connections and the excitation in the wrong direction probably due to battery current having been sent through the machine on the bench test at the time of replacing the brushes. When the commutator connections had been re-soldered and the machine was run on the bench with the excitation correct, and no other item altered, it appeared to be all right with the exception that the output was rather high, i.e. at the end of 20 minutes on it was 14.1 amperes instead of just over 11. When run on maximum load for several Contd. | ||