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).
Compromises for dynamo systems, focusing on using field resistance to regulate output.
| Identifier | WestWitteringFiles\O\2April1926-June1926\ Scan209 | |
| Date | 12th June 1926 | |
| Contd. -9- EFC1/T12.6.26. COMPROMISES BETWEEN THE TWO EXTREME TYPES OF DYNAMO SYSTEM. One such compromise of a comparatively simple nature, which was sometime back mentioned in our EFC3/T22.6.22, is to utilise the ordinary type of so-called inherently regulated dynamo and provide a field resistance which, when electrically inserted into the main excitation circuit of the machine, causes the ampere-speed output curve of that machine to suffer considerable reduction. In the particular case referred to, the mechanical operation of putting on the head lamp switch also has the effect on another switch of short-circuiting this series resistance and causing the dynamo to run at full output. At every time then, when the head lamps are not in use, the dynamo is running at a reduced rate of charge and its cutting-in point will be correspondingly a little later. This arrangement suffers from the disadvantage that where a lot of town running is done in the summer months, there possibly would not be adequate means of charging the battery to make up for the demands of the starter motor, though no doubt in the cases of cars used principally in the open country, the scheme would be an advantage from several points of view, two of which are (1) Absence of excessive voltage on ignition and side lamps. (2) Prolongation of life of battery due to reduced rate of charge. Contd. | ||