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 function of the fuses on the Lucas junction box and the consequences of earth faults.
| Identifier | ExFiles\Box 26\2\ Scan051 | |
| Date | 6th October 1919 | |
| contd. -16- EFC2/T6.10.19. FUSES ON JUNCTION BOX. On the Lucas junction box there are two fuses connecting the main positive and negative terminals to the main positive and negative bus bars respectively. If an earth occurs on any conductor connected to the negative terminal of the battery, the positive fuse will, or may, go so as to get rid of the simultaneously existing earth on the positive side, but only may go if the earth occurs on some portion of the system connected to the negative bus bar, because there is then an equal chance of the negative fuse going. If an earth occurs anywhere on the positive side of the system nothing will at once happen as the positive side is already earthed. It is most undesirable, however, for an earth to exist on this side other than the intentional earth on the positive bus bar, because under such circumstances, a simultaneous earth occurring on the negative side might lead to serious consequences. The portions of the system which are put out of action by the positive fuse going are ;- 1. Battery ignition. 2. Klaxon Horn. 3. Any other apparatus connected to the positive bus bar. The relay circuit of the starter motor is not put out of action. The portions of the system whihh are put out of action by the negative fuse going are as above, with the Contd. | ||