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).
Query and report on improving the dynamo control brush accessibility for the 20/25 HP model, comparing it to the Phantom.
| Identifier | ExFiles\Box 62\3\ scan0168 | |
| Date | 31th January 1931 | |
| X6065 To E.{Mr Elliott - Chief Engineer} from EFC. c. Hy.{Tom Haldenby - Plant Engineer} EFC4/AD31.1.31. X.6065. X.6066. 20/25 HP. DYNAMO CONTROL BRUSH ACCESSIBILITY. Is there any reason why the control brush accessibility of the 20/25 dynamo should not be improved by the method adopted on the Phantom as a result of which it is possible after releasing the fastening of a single strap to turn the machine in its cradle with a view to presenting the control brush conveniently to the observer? In this connection, the following report AD.82 from my assistant gives the matter in more detail :- "On Phantom dynamos both for right and left-hand chassis, the machine is located by a pin formed by an extension of one of the field pole screw heads. This registers with a slot in the crankcase. Loosening the dynamo strap allows the machine to be turned so that control brushes may be conveniently handled. Normally the main brushes are uppermost, but turned slightly outward so that they are easily accessible without disturbing the fastening of the machine, while the control brushes are underneath and toward the engine where they are practically out of reach, until the machine is turned. On the 20/25 car the dynamo is located by a special pin screwed into the carcase. This fits into a hole instead of a slot in the crankcase and consequently the machine cannot be turned by merely loosening the straps (of which there are two, as compared with one on the Phantom) but must come away from the crankcase. We do not know of any reason why it should not be arranged in the same way as the Phantom. As in the above cases the 20/25 machine is located with main brushes near the top and easily accessible while the control is toward the crankcase though it can, with difficulty, be reached from above. This was made possible by turning the machine through 28° some years ago". EFC. | ||