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).
Notes on the proposed three-charge electrical scheme for the 20/25 model.
| Identifier | ExFiles\Box 163\6\ img220 | |
| Date | 17th October 1932 guessed | |
| NOTES ON THE PROPOSED 20/25 THREE CHARGE SCHEME. With the switch lever in the summer charge position two resistances are in series with the dynamo field, one of these being relatively higher than the other. This condition obtains for all day running with the switch in this position. With the switch in the winter charge position for day running, the highest value of resistance of the two mentioned above is short circuited, the dynamo rate of charge being correspondingly increased. Thus for all day running conditions, either winter or summer, full charge from the dynamo is not available. For night running conditions, with the side and tail lamps on and with the switch in the summer charge position, the conditions of the dynamo are the same as winter charge day running - i.e. the operation of putting on the switch to side and tail automatically cuts out the larger value of resistance unit. Thus for side and tail position, either winter or summer, it is impossible to have the two resistance units in series with the dynamo field. Upon switching on the headlamps however, whether running on the summer or winter charge position of the switch, both resistance units are short circuited thus giving the full output of the dynamo. It is therefore impossible to run the headlamps without getting full charge from the dynamo. There is really therefore no need for the driver to switch off the charge, and the ignition and charge are therefore coupled together on the switch. | ||