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).
Adjusting the control brush angle on a 20/25 dynamo for safe operation without field resistance.
| Identifier | ExFiles\Box 163\6\ img231 | |
| Date | 5th November 1932 | |
| X6016 BY/RD. from Hs{Lord Ernest Hives - Chair}/Wst. Hs{Lord Ernest Hives - Chair}/Wst.2/KT.5.11.32. 20/25 TWO RATE CHARGE DYNAMO FOR RUNNING WITHOUT FIELD RESISTANCE. We have found that in order to make the standard 20/25 dynamo safe for all conditions of running, i.e. without any field resistance it is necessary to give the control brush an approximate average angle of 127° measured from the positive brush. A dynamo so arranged should not overheat, this being the approximate setting of the dynamo which was fitted to Mr. Cadbury's 20/25 chassis which had not the two rate charge scheme fitted. The standard setting is 126°. Hs{Lord Ernest Hives - Chair}/Wst. | ||