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 General Electric Co. Ltd. explaining test result differences for a U.4 valve, with accompanying circuit diagrams.
| Identifier | ExFiles\Box 41\2\ Scan050 | |
| Date | 28th January 1927 | |
| X3646 EFC3/T. 28th January, 1927. Messrs. The General Electric Co.Ltd., Magnet House, Kingsway, LONDON, W.C.2. Dear Sirs, We thank you for your letter ref. WHW/FEH of the 27th inst. with enclosed pencil curves of the U.4 valve, which curves we now return. We think the matter is now sufficiently well explained. The difference lies in the fact that our test was made by delivering directly into a large battery (as diagram III here given) of varying terminal voltage in accordance with figures given in our sheet dated 11.12.26, which undoubtedly represent the curve of delivery in this way, the only resistive or reactive impedance in the delivery circuit being the relatively small impedance in the milli-ammeter itself. III. [Diagram III Annotations] 189 ~ Volts Milli Amperes Volts Contd. IV. [Diagram IV Annotations] Two chokes each 30 henries 1150 ohms. Three condensers each 2 µf Weston 150 Volt Meter | ||