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 from The General Electric Co. Ltd. regarding a U.4 type Rectifying valve.
| Identifier | ExFiles\Box 41\2\ Scan043 | |
| Date | 1st January 1927 | |
| CONTRACTORS TO H.M. ADMIRALTY, INDIA OFFICE, WAR OFFICE, G.P.O. AND THE LEADING HOME AND OVERSEAS RAILWAYS. REGISTERED TRADE MARK Y3646 Telephone (LONDON). REGENT. 7050 (50 LINES) Telegraphic Address: ELECTRICITY, WESTCENT, LONDON. The General Electric Co., Ltd. MANUFACTURERS OF EVERYTHING ELECTRICAL. Cable Address: POLYPHASE, LONDON. Codes: WESTERN UNION (5 LETTER EDITION) A.B.C. 5TH EDITION. STEVENS ENGINEERING, BENTLEY'S, COLE AND PRIVATE. YOUR REF. OUR REF. WHW/FEH.908 TELEPHONE EXTENSION 8 TO ENSURE PROMPT ATTENTION PLEASE QUOTE ABOVE REFERENCE. HEAD OFFICE Magnet House. Kingsway. LONDON, W.C.2. 1st January, 1927. Messrs. Rolls Royce Ltd., DERBY. Dear Sirs, We are exceedingly sorry for the delay in replying to your letter of the 11th December, ref:EFOI/T, which gave us a very detailed report on our U.4 type Rectifying valve. In the first place, we wish to point out an error on the valve box. Apparently the box which you have reads "50 m.a.". The correct output value is 15 m.a. maximum, and we have now corrected this mistake. It would appear that your query arises from the fact that you have not realised that our readings are taken with moving coil instruments, and no smoothing apparatus of any kind. It is obvious that with suitable condensers the voltage at no load will rise to the peak value. In regard to the suggestion for an increased rating for the U.4 type, taking everything into consideration, we do not think it safe to recommend much of an increase in the maximum rectified current, but if you think the matter is of sufficient importance we will arrange for trials to be carried out to see what effect on life an increased rating would have. If you particularly require a valve capable of giving a larger rectified current, we would recommend you to experiment with the U.5 type valve, which could, if necessary, be connected with the two anodes joined to form a single-wave rectifier. A leaflet giving full technical data for the U.4 WORKS WITTON, BIRMINGHAM. COVENTRY. MANCHESTER. HAMMERSMITH. WEMBLEY. LEMINGTON-ON-TYNE. ERITH. SOUTHAMPTON. LONDON. BRANCHES ABERDEEN, BELFAST, BIRMINGHAM, BRISTOL, CARDIFF, CORK, DUBLIN, DUNDEE, EDINBURGH, GLASGOW, HULL, IPSWICH, LEEDS, LIVERPOOL, MANCHESTER, NEWCASTLE-ON-TYNE, NOTTINGHAM, SHEFFIELD, SOUTHAMPTON, SWANSEA. OVERSEAS BRANCHES AUSTRALASIA SYDNEY, MELBOURNE, PERTH, ADELAIDE, NEWCASTLE, AUCKLAND, DUNEDIN & WELLINGTON. CHINA & MANCHURIA SHANGHAI, HONG KONG, AND DAIREN FEDERATED MALAY STATES & STRAITS SETTLEMENTS SINGAPORE FRANCE PARIS INDIA CALCUTTA, BOMBAY, MADRAS & LAHORE. SOUTH AFRICA JOHANNESBURG, CAPE TOWN, DURBAN & PORT ELIZABETH. SOUTH AMERICA BUENOS AIRES. AGENCIES IN ALL OTHER PRINCIPAL TOWNS THROUGHOUT THE WORLD. ENCLOSURES. TO ENSURE PROMPT ATTENTION MATTERS REFERRING TO VARIOUS DEPARTMENTS SHOULD BE WRITTEN ON SEPARATE SHEETS. | ||