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).
Proposal for an accumulator charge indicator using a green lamp scheme, including a circuit diagram.
| Identifier | WestWitteringFiles\T\2July1928-December1928\ Scan286 | |
| Date | 26th December 1928 | |
| EFC. - E.{Mr Elliott - Chief Engineer} } FROM R.{Sir Henry Royce} (At Le CanadelHenry Royce's French residence.) R1/M26.12.28. REC'D AT WW. 31.12.28. X4660 ACCUMULATOR CHARGE INDICATOR. GREEN LAMP SCHEME. It should be understood that this is not essentially an SS.{S. Smith} feature. It can (or need not) be used on this or any other chassis. It is now nearly correct and is very useful. It should do little harm because it is only an indicator which the driver can believe or ignore, but it seems to save (1) the battery, (2) distilled water, (3) the dynamo, so is probably worth its cost. We have been troubled by the current finding unsuspected circuit, and has brought us into a state where it either introduces additional parts or prevents us doing other good things. Perhaps the chief reason of our trouble is due to our scheme of fitting the auto: charging switch on the negative brush lead. My original sketch shewed the green lamp magnet and the auto: switch on the + brush lead, in which case we may get away from our trouble, but I have not time and energy at the moment to trace it all out, so send it along for E.{Mr Elliott - Chief Engineer} and EFC. to examine. Sketch shews my suggestion. [DIAGRAM] To SWITCHBOX. Green light magnet comes in after auto: switch cuts in dynamo. The switchbox joins battery + and dynamo + but auto: is broken and exitation is broken. Auto: does nothing until exitation is made, then voltage rises until auto: makes contact *. Green lamp magnet is exited but it is at battery voltage and should be OK. Actually this seems simpler than at present - i.e. one wire less as dynamo A.{Mr Adams}- can be earthed at dynamo. Fuse can be in two places but I think between dynamo + and auto: The switchbox is not altered in any way, and modifications to distribution board etc seem quite simple. I do not like any of the alternatives that have been suggested because they are not simple and robust, and depend on fine timing adjustments. At least this gives a fresh aspect, with perhaps several possibilities. R.{Sir Henry Royce} | ||