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 failure of a dynamo positive fuse and its effect on the charging and lamp systems.
| Identifier | WestWitteringFiles\S\June1928-August1928\ Scan106 | |
| Date | 24th July 1928 guessed | |
| -2- Contd. when there was a failure of the dynamo positive fuse, and also that the supply of the lamp itself should be connected as near to the battery as possible, so as to afford less chance of the lamp being burnt out by the high voltage before it had time to be noticed. One might even go so far as to suggest what is really perhaps an impracticable scheme, that the lamp might be lit independently from a small dry battery carried for the purpose. I think there is no doubt that some cutout shunt coils have failed through a failure of the armature fuse as suggested, because in that case there is no definite indication of anything wrong except that the ammeter shews no charge and probably little notice would at first be taken of the fact. We have had cases (perhaps two) when the cutout shunt coil has been burnt out without any apparent damage to the dynamo. Even with a high voltage the coil would take time to roast. In the case of the danger lamp unit the same would apply but our reason for considering connecting it to B at all is the fact that since this causes the lighting of the lamp, the driver is informed of the fact that the charging switch needs switching off. If we regard the green lamp switch unit purely as an indicator for overcharging in normal operation and in no sense as a danger indicator, then we agree that these arguments do not apply. But even so, we have the difficulty that if we have a common positive terminal to the greenlamp switch unit and supply this from C, we have to supply the lamp current through the field fuse, and as this lamp current is a good deal more than | ||