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 negative effects of a 20 HP dynamo modification intended for silencing.
| Identifier | ExFiles\Box 165\6\ img034 | |
| Date | 13th October 1926 | |
| To HY.{Tom Haldenby - Plant Engineer} from EFC. c. Mr. Brock. X5.660 EFC2/T13.10.26. X4 20 HP. DYNAMO WITH POLE PIECES MODIFIED FOR SILENCE. I do not know whether it was proposed to make this modification on the 20 HP. machines. However, we have tried out the effect on the output characteristic of this modification as actually made to one of our machines by Mr. Brock, and we find the alteration to the curve, even at the best setting of the brushes, to be even greater than in the case of the 40/50 HP. machine, and so great a deviation from our curve of minimum requirements that we consider this should not be passed for production test. We are keeping a record of the two types of curve. This only confirms our previous experiment on poles of this type which we made a considerable time ago. (This was reported in our EFC3/T15.10.23, copy of which was sent to HY{Tom Haldenby - Plant Engineer}/RD.). As recently stated, we had at that time arrived at the conclusion that such an alteration to the poles made too much disturbance in the output of the machine. EFC. | ||