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).
Letter describing a new voltage-operated relay device for controlling the charging rate of car accumulators.
| Identifier | ExFiles\Box 59\1\ Scan358 | |
| Date | 29th April 1930 | |
| EFC. Will you please let me have your views X4008 By/Csh Ryecroft The Park BUXTON. Derbys. April 29th. 1930. Messrs. The Rolls Royce Motor Co. Ltd. Dear Sirs, I have a device which has been in use now for some time on my own car for controlling the charging rate of the accumulators. There are, I believe, numerous ways of doing this but none that is really satisfactory as they cannot be made sufficiently sensitive, or accurate, on account of the vibration of the car and road shocks. My device is, for all practical purposes, as immune to shocks as the ordinary "cut-out" fitted in the usual electrical equipment of a car. The principle of my device is a voltage operated relay of, I believe, entirely new design. This relay can be set to operate at any predetermined voltage, and is absolutely positive and immune to all shocks. On my model instrument it is set at 7¼ volts as the lighting set is of the 6 volt type, but without any trouble the setting can be varied from 5 volts to 8 volts as required, and within similar limits on different voltage lighting sets. The relay is sensitive to ⅛ of a volt variation and as an electrical instrument could be made sensitive to much smaller variation. On starting the engine the dynamo charges the accumulators at the full rate automatically. As the accumulators | ||