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).
Comparison between a green indicator lamp and an auto switch for the dynamo charging system.
| Identifier | ExFiles\Box 59\1\ Scan293 | |
| Date | 29th March 1928 guessed | |
| -3- Contd. chassis frame, the green lamp would burn out probably without being noticed, and certainly before there was time to put the switch off to prevent such burn out. In this way it does not give the same protection as the auto switch, which gives audible and visual indications without doing any harm. Further to this, if the dynamo battery circuit is broken in certain other places, and the green lamp gives its indications normally (being lit by the battery) there is nothing to indicate that there is any more existence of danger than in the normal indication given by the green lamp for the high voltage of the system in normal operation. The driver may therefore be not particularly concerned about turning off the charging switch in a hurry and damage may be done. (6) With the green lamp scheme arranged in such a way that the green lamp goes out when the charging switch is put off, there is no indication as to when the charge should be put on again, whereas the auto switch will do this automatically. (7) We can increase the dynamo output at high speeds but if or when we do so the auto switch becomes all the more necessary, both absolutely and in its relative value to the green lamp scheme. EFC. | ||