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).
From EFC to Da discussing the wiring arrangement of fuses in the dynamo main circuit.
| Identifier | ExFiles\Box 61\2\ scan0382 | |
| Date | 31th August 1920 | |
| X.2515. To Da.{Bernard Day - Chassis Design} from EFC. EFC2/T31.8.20. X.4164 X.3954 X.2515 - RE FUSES In answer to your note Da{Bernard Day - Chassis Design}3/CB27.8.20, the standard wiring arrangement has certainly not been changed so as to include a fuse in the dynamo main circuit. This would not have been done without your knowledge. We have, however, had two special switchboxes from Messrs. Lucas arranged in this manner, one of which is now fitted to chassis 1 EX. I find it very difficult to appreciate that arrangement Fig.2, under cover of our EFC3/T25.8.20 sent to R and replied to by him in his R8/G27.8.20, is really essentially better than Fig.1, provided the fuses are non-interchangeable, as they would be in the Smith system where the field fuse in on the cut-out. The main fuse can be made so much safer in Fig.1 and can be, of course, of copper wire. In any case, if it fails, the field fuse should go also next time the machine is run up. If the main field fuse fails in Fig.2, the dynamo field is left on the battery and the armature may possibly get roasted owing to the large amount short circuited by the brushes when the dynamo is driven. As the matter stands at present with Messrs. Smith, we have asked for three Smith switchboxes incorporating the fuse in the fig.1 position. I am, however, writing them to-day to ask them to deliver the three boxes with the three alternative | ||