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).
The functionality and operating parameters of an auto switch dependent on battery voltage rise.
| Identifier | WestWitteringFiles\R\2December1927-February1928\ Scan161 | |
| Date | 2nd February 1928 | |
| -6- Contd. "The functioning of our auto switch depends upon the final rise of voltage. We would like the operating point to occur in the later stages of this pick-up in order to feel that the battery was getting more nearly what it would get on constant current charge. For safety of operation, however, we cannot do this, but must choose a point lower down on this final rise of voltage, but not too near the horizontal portion. Is the functioning of the battery upset to any extent, and if so, to what extent, by cutting it off before the final pick-up of voltage is effected ? That is what we do not know for certain. We think it possible that the battery may gradually lose ground so to speak in the sense that its elements may not remain in first class condition, though our experiments so far rather indicate that this is not necessarily the case. We should like your comments." In answer to this we received the following :- " With regard to the question you raise as to whether a battery will gradually lose ground in the sense that its elements may not remain in first class condition if the circumstances are such that the P.D. across its terminals can never rise above a figure which is determined by the setting of the instrument would appear to depend primarily on the operating point chosen. If the battery gets a fair amount of work and is never exhausted its functioning should not be appreciably upset provided the auto-switch operates nearer the peak than the horizontal portion. If a battery is exhausted and infrequently worked, I would expect some deterioration in the elements if the final pick-up of voltage is not effected. You observe in the first part of your letter that the switch operation is affected by the temperature of the coil, we presume you have not overlooked the fact that the P.D. across the battery terminals will be affected by the temperature of the electrolyte ? " The auto switch position therefore would now appear to be this:- (1) That the unit itself has every prospect of working entirely satisfactorily. (2) That it provides a large amount of protection against faults on the system not otherwise provided. Contd. | ||