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).
Design and implementation of a dynamo two-rate charging system for a car.
| Identifier | ExFiles\Box 163\6\ img108 | |
| Date | 23th December 1930 | |
| EFC. E.{Mr Elliott - Chief Engineer} ) FROM R.{Sir Henry Royce} Ry. Hs.{Lord Ernest Hives - Chair} ) (At Le CanadelHenry Royce's French residence) c. Sg.{Arthur F. Sidgreaves - MD} Wor.{Arthur Wormald - General Works Manager} PN.{Mr Northey} X6016. R2/M23.12.30. X.6016. CAR WORK - DYNAMO TWO RATE CHARGE X.8780. (1) I fear the scheme suggested by EFC's memo of 12.12.30. is very confusing, and perhaps we are losing sight of the original idea of the scheme, as suggested by EFC. and E.{Mr Elliott - Chief Engineer} (2) Also as far as I can see there is nothing wrong with the specimen we have here of the arrangement proposed for standard. There must have been something quite different with the model fitted to SG{Arthur F. Sidgreaves - MD}'s car, which was stated (I believe) not to cut in until 25 M.P.H. Our 18-EX Dodd says - cuts in at 13 MPH. and is charging constantly on the deadly slow roads at 10 amps. (3) The scheme originally prevented the dynamo putting too large a current through the battery, which if the dynamo gave enough (and a small margin) for night travelling with usual powerful head and other lamps on, it was too great for the life of the battery, and a waste of liquid requiring frequent refilling and reducing the life of the battery. If this is not so why have anything less than the maximum from the dynamo. (4) I got the impression that we could not have the two rate scheme in its simple form and still cut in at sufficiently low speed. (5) Suppose therefore we leave the original connection and use only a smaller resistance which is cut out only when the head lamps are connected, our half charge being a full charge for the battery but not an overcharge. (6) If we leave anything to the driver he will turn on the full charge always and leave it so, because he will be afraid of his battery being down, and perhaps has little interest in the life of same, and we should be going to all our trouble of inter-connecting and providing resistance and contacts for no purpose. Perhaps I am partly to blame, as stated in para.4. but someone else fitted a wrongly proportioned specimen to Sg{Arthur F. Sidgreaves - MD}'s car if reports are correct, which I doubt. R.{Sir Henry Royce} | ||