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 failure of a 20 HP dynamo from chassis GA.54, detailing issues with the control brush setting and commutator micas.
| Identifier | ExFiles\Box 57\2\ Scan058 | |
| Date | 15th December 1926 | |
| X5763 do To EY. from EFC. c. SFT{Mr Swift}/Mr. Brock. EFC8/T15.12.26. 20 HP. DYNAMO No.580. EX CHASSIS GA.54. REF. Mr. Brock's note of 6.12.26. This is a 29 commutator segment machine. We consider that the failure of this dynamo has been brought about by the following :- (1) The control brush setting is somewhat too far retarded, being 119° in place of 122°. (2) The commutator micas are not undercut and project a little. This has, in addition, caused the brushes (particularly the control brush) to be worn away more quickly than normal. There does not appear sufficient evidence to conclude that this machine has been run on open circuit. The dynamo is returned to Mr. Brockley. EFC. | ||