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).
Dynamo output, electrical load, and proposed running conditions for vehicle testing.
| Identifier | WestWitteringFiles\W\May1931-August1931\ Scan009 | |
| Date | 6th May 1931 | |
| -2- contd. our lamp load at all speeds. On the 40/50 car for the head lamps, ignition, side and tail we take 13 amperes. In the past we have had numerous complaints of the lack of output on the 40/50 dynamos but we have always been able to satisfy customers when we have modified their machines to give an output which is no more than the latest improved machine, in fact slightly less. We therefore hold the view that with this latest machine we ought to have no complaints as regards not being able to keep the battery charged. Another point is that it is practically certain that legislation will be introduced in this country next year limiting the head lamps to 36 watts each - at present we are using 60 watts each. We have to remember, however, that customers on the Continent would still demand powerful lamps and also the number of current consuming devices on a car are likely to increase rather than diminish. A further point is that when we do away with the magneto we shall take more current for the ignition. The next point to be considered on the dynamo is the method of control. We are not entirely satisfied with the two charge scheme. We think in running the car the conditions can be defined in three categories :- (1) Summer time running - Lamps hardly used. Small amount of charge necessary only, just to look after the ignition etc. (2) Winter time conditions in Town. - This means that the car may be parked for long times with the side lamps on - considerable amount of starting and long periods of lighting. (3) Winter high speed driving - Head lamps on continuously for long periods. With the two charge scheme, in order to satisfy No. 2 condition we cannot have much resistance in the field because this gives us a late cutting in which is fatal for traffic conditions. For No. 1 condition we could work with a greater resistance. | ||