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 disadvantages of the Goshawk electrical system and a proposal for a semi-earthed system for lamp circuits.
| Identifier | WestWitteringFiles\J\December1922\ Scan62 | |
| Date | 12th December 1922 | |
| Contd. -2- EFC/TB.12.22. are no fuses in the lamp circuits so that an emergency fuse would be provided for these circuits by converting the lamps to single pole and returning the lamp currents to earth. (On the 40/50 system at present the only apparatus for which the currents have to pass through this earthing fuse are the ignition, Klaxon horn and body lighting.) Should this fuse go, then the lamps are put out as well as the battery ignition. The occurrence of such a short on the lamp circuit, however, would be more serious, without the fuse, particularly as no lamp distributing fuses are provided in this 40/50 case. It is not our suggestion that all the distributing fuses should be dispensed with, but rather that this negative earthing fuse be considered more of the nature of an emergency fuse which, by failure, does not introduce the disadvantage which we have at present on the Goshawk system. The disadvantage to which we refer is that as at present arranged, though practically all live wires are protected in emergency, when this emergency happens so that the fuse goes, or if the fuse is intentionally removed, then the dynamo is capable of over-voltage which may damage itself or the lamps. It therefore appears to us that the suggested semi-earthed system should be the most generally satisfactory, though we realise that it involves the disadvantage of having to provide two insulated terminals on the motor. EFC. | ||