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).
Continued discussion on the effectiveness and capacity of fuses in main negative, control, and field circuits.
| Identifier | WestWitteringFiles\D\February1920\ Scan7 | |
| Date | 2nd February 1920 guessed | |
| Ckl/T3.2.20. -5- Contd. both the main negative and control fuses may fail to go. It will be seen, giving due consideration to the fact that the fuses used in the investigation were only of 12 amperes capacity, and that safe fuses for normal running conditions could reasonably be of 20 amperes capacity for the control and of 15 amperes capacity for the main negative, the placing of main negative and control fuses of suitable capacity to remain intact under all normal conditions, will not necessarily offer the protection desired, and this leads one to the conclusion that fuses in the main negative and control circuits are of very limited value. On the other hand, a fuse in the field circuit does offer a definite protection to the dynamo should at any time the battery become disconnected. It appears to be the practice of most concerns to fit a fuse in the field circuit only. On the Lucas lighting set for motor cycle lighting, a different scheme is adopted, which would appear to offer more protection against the sticking of the cutout than either of the Lucas schemes:- 1. Fuse in main negative circuit only. 2. Fuses in both main negative and control circuits. This consists of using a single fuse for both the negative and the control circuits, making use in this case of three separate two-point switches mechanically connected, as (only two of which are necessary to correspond to scheme under consideration) | ||