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).
Instructions and troubleshooting for the switchbox, specifically the field fuse and dynamo charging system.
| Identifier | ExFiles\Box 26\2\ Scan124 | |
| Date | 19th July 1917 guessed | |
| -10- Contd. SWITCHBOX. The function of the field fuse is to protect the dynamo against damage by overheating if it be run with the charging switch on and the battery disconnected from any cause, in which circumstances the field fuse will readily be melted. Special care should be taken that this fuse is gripped firmly in the fuse holder, as a loose contact may cause the fuse to melt unnecessarily, or prevent the dynamo from exciting. Test the grip by gently pressing on the middle of the fuse wire with the end of a match stick. Should the ammeter not show any charging current with the charging switch on, lamps off, and dynamo running, confirm that the battery connections are sound by inspection and by trying the head lamps with the dynamo not running, and if any irregularity be found, first rectify this, then inspect the field fuse and if necessary, replace with spare found in small container in switchbox. In the unlikely event of no charging now taking place, the fault must lie in the dynamo or dynamo connections and it will be necessary carefully to inspect these. One cause of failure to charge would be the existence of an earth on field, negative, or control leads from the switchbox to dynamo (see under "Tracing an Earth"). The lighting of lamps or operation of any other part of the electrical system direct from the dynamo with battery either intentionally or unintentionally disconnected must be avoided. In these circumstances, the dynamo is protected | ||