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).
Test results and potential solutions for maintaining dynamo output at high speeds.
| Identifier | WestWitteringFiles\W\May1931-August1931\ Scan024 | |
| Date | 21th May 1931 | |
| ORIGINAL. To R.{Sir Henry Royce} from Hs{Lord Ernest Hives - Chair}/CAP. c. Sg.{Arthur F. Sidgreaves - MD} Wor.{Arthur Wormald - General Works Manager} c. E.{Mr Elliott - Chief Engineer} Da.{Bernard Day - Chassis Design} c. By.{R.W. Bailey - Chief Engineer} HS{Lord Ernest Hives - Chair}/CAP8/MJ21.5.31. X6099 DYNAMO OUTPUT. With reference to your suggestion on standardisation sheet 6016 that a new position of control brush may possibly maintain the output at high speeds. We have found by tests that when the control brush is moved to a position nearer the positive main brush it does tend to keep the output up at high speeds, but it also increases the output more on the peak. In effect, altering the position of the control brush does not materially alter the shape of the output curve. The limit of output is fixed by the maximum working temperature of the dynamo. This we run as high as we think is safe. In order to maintain a better output at high speeds, we have found a partial solution to this in the use of a field winding wound with a smaller gauge wire having a higher resistance, and which naturally requires the control brush to be nearer the main positive. We made tests with this some time ago but at that time the dynamos already had a late cutting in point and this scheme makes it slight worse. We suggest however that now we have improved the point of cutting in this is worth trying again. We are also investigating this in connection with your series winding. HS{Lord Ernest Hives - Chair}/C.A. Pignatt. | ||