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 electrical configuration of a green lamp and shunt coils to prevent circuit failure.
| Identifier | WestWitteringFiles\S\June1928-August1928\ Scan098 | |
| Date | 1st July 1928 guessed | |
| -2- Contd. the green lamp is not lighted. Even at present the field fuse cannot be an absolute protection against burning out of the dynamo resulting from a broken battery circuit, because if it were sufficiently fine to be so initially, the repeated heating, resulting in oxidation of the wire (even if tinned) would ultimately lead to failure of the fuse in normal running. I am afraid we shall have to feed the green lamp from a separate source. We have already increased the current to pass through the field fuse by the two small currents to feed the two shunt coils. Of these two shunt coils (1) We cannot have both on B, or cutout shunt coil on B and green lamp shunt coil on C, for reasons stated. We can only have either (2) Both on C as at present, or it might become necessary, if the current through the field fuse is still too great, to have (3) The cutout shunt coil on C and the green lamp shunt coil on B, making still another terminal in the combination of units. This must be determined by tests, though I do not regard it as likely that we shall have to depart from both coils being connected to C. When the matter is examined, however, I think it will be agreed that we should not supply the lamp itself from C. EFC. | ||