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 to H.D. Symons & Co. Ltd. discussing the suitability of rectifying valves for testing equipment.
| Identifier | ExFiles\Box 61\1\ scan0181 | |
| Date | 11th March 1931 | |
| Mr. Symons, Messrs. H.D. Symons & Co.Ltd. Kingston Hill, Surrey. 11th March, 1931. -4- In regard to the type of rectifying valve used on the rectifying unit, this has so far been a G.E.C. type U.3. which, however, is now stated to be obsolete and in any case has not been entirely suitable. It has been more suitable for the testing of materials of inferior insulating qualities because of its capability of giving a greater current at a smaller rectified pressure than in the case of the spark gap rectifier. Hence, up to the present it has been more suitable to use the spark gap rectifier for tests where the greatest pressure has been required with the lowest leakage current as shown on the microammeter. Recently, however, we have been in correspondence with the Edison Swan Electric Co. with a view to obtaining a valve of more suitable characteristics in which case its use would be definitely preferable to the use of the spark gap rectifier. For this reason a copy of the specification of a suitable rectifying valve has been included in the matter enclosed. The sphere gap H.T. voltmeter not only measures the potential of the H.T. D.C. main but acts as a regulator of the pressure thereupon, as temporarily when a spark takes place between the balls the pressure of the main is lowered. We have suggested to the Edison Swan Co. that if a valve to our specification were marketed and advertised to various test laboratories throughout the country, a number of these could be sold for a similar purpose to that described above. Yours faithfully, FOR ROLLS-ROYCE LIMITED. | ||