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).
Procedure for tracing an electrical earth fault in the dynamo and switchbox system.
| Identifier | ExFiles\Box 26\2\ Scan136 | |
| Date | 15th March 1920 guessed | |
| -22- Contd. removed. The negative and control leads from dynamo to switchbox may be looked upon for this purpose as in direct connection with the positive side of the system. An earth on the field connection from dynamo to switchbox, although causing the dynamo to fail to excite, as described on p.10. would not permit the battery ignition or the horn to be operated with the positive fuse removed, as the resistance of the field winding would limit the current. In order to trace, if necessary, this kind of earth, first see that all switches are off and that the junction box fuses are removed, then earth the negative junction box terminal. A current of about three amperes indicated by the ammeter will show the existence of such an earth. | ||