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 protection, fusing systems, and the volt-ampere characteristics of 'inherently controlled' dynamos.
| Identifier | WestWitteringFiles\J\November1922\ Scan47 | |
| Date | 3rd November 1922 | |
| Contd. -2- EFC1/T3.11.22. current to remain at a reasonable value (either steady or falling) for further increase of speed, after the maximum output has once been reached. In order to afford protection to such a dynamo and to the battery with which it is run, various schemes of fusing are used. In the nature of things no system of fusing can be entirely satisfactory and there is really no best system owing to the varying circumstances of the case. It is therefore a matter of opinion as to what fusing system should be adopted, though we do not intend to discuss this further at this point. There is another objectionable feature of the so-called 'inherently controlled' dynamos (on any and every system) namely that although all these dynamos possess intrinsic volt-ampere characteristics somewhat similar to those of ordinary shunt machines, nevertheless they are not working, except at slow speeds, on the top part of the characteristic where an increase of amperes is accompanied by a decrease of volts. They are, on the other hand, nearly always working on the lower portion of the characteristic where the increase of volts and increase of amperes occur together. The result of this on the chassis system is that the higher the E.M.F. of the battery or the P.D. of the battery light system, the more current is generated by the dynamo, tending to further increase the E.M.F. or P.D. Contd. | ||