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).
Examination report on a faulty Dynamo No.101 and distribution box from Chassis 48-G-4, detailing issues of overheating and excessive output.
| Identifier | ExFiles\Box 47\4\ Scan183 | |
| Date | 10th May 1924 | |
| X4383 To BY.{R.W. Bailey - Chief Engineer} from EFC. EFCK/T10.5.24. X.4383 - DYNAMO No.101 AND DISTRIBUTION BOX EX CHASSIS 48-G-4. FIELD. We have carefully examined the distribution box and confirmed the finding of EP{G. Eric Platford - Chief Quality Engineer}'s Dept. that there is nothing intrinsically wrong with this box with the exception that the contacts are not exactly opposite, a slight fault which would appear to have existed originally. It is true that the contacts are somewhat burnt, but this we think would be accounted for by the faulty dynamo action as below. Regarding the dynamo, this is a moderately early machine. There is no evidence of mica projecting between the commutator segments being the cause of the trouble. On the other hand there is evidence that the trouble has been due to excessive output, caused by an erroneous position of the control brush, as it is obvious on inspection that the control brush is distinctly more retarded than on the average machine. It seems therefore probable that the bedding was not quite correct in the first instance when the machine was set to the production test, a condition which would allow the dynamo output to increase as the bedding became better. We were able to demonstrate that the throwing of the solder was due to heating, which in its turn was due to over output, because by running the machine on a slightly exaggerated terminal volt-ampere characteristic it was readily possible to melt the temporary solder from the commutator connections, the carcase temperature of the dynamo being 80°C as against the corresponding reading of 71.5°C of a normally correct machine, but set for slightly higher output, then normal. There was no evidence that the failure of the machine was due to a broken battery circuit. We return the distribution box and dynamo in a test condition (solder thrown) to BY.{R.W. Bailey - Chief Engineer} herewith, together with BY2/H29.4.24. EFC. | ||