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).
Extract discussing modifications to a Lucas dynamo, focusing on the switch box, fuses, switches and contacts.
| Identifier | ExFiles\Box 61\2\ scan0448 | |
| Date | 20th April 1921 | |
| X 2575 Extract from R4/G20.4.21. RE LENGTHENED LUCAS DYNAMO. X.3749. X.2515. Having seen to these modifications we must return to the switch box. It will be understood that we wish the fuse carriers to be of a more reliable pattern than the Lucas type, that the fuses should be of copper wire, and not tin or lead. They should be of ample dimensions, as fuses cannot be made delicate enough to melt at an overload current, and they can only act in case there is a short circuit. Regarding the switches, Mr. Hives report that there has been no direct evidence of these failing to work. My own impression, however, was that they were hardly as reliable as is desired, owing to the very short length of the flexible part of the contacts. X.4349.X.1815. Regarding the automatic accumulator switch, the magnetic principle embodied in the experimental one sent is undoubtedly better than the single coil type. We notice, however, that this particular polarised type was made by the Westinghouse Company of America some long time ago. Whether the Westinghouse have a patent for this scheme I do not know, but I should doubt if any such patent would be valid as it embodies such well known principles and probably used on some of the earlier accumulator switches. Regarding the contacts, we think something better than copper should be used, and should prefer a combination of carbon and silver acting in the usual way of the carbon making the circuit slightly in advance of the silver, and breaking it slightly in retard of the silver. Contd. (Upside down text) M.M. 238A. (1000) ('S.H.') 10-12-'20. G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 2347 | ||