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 Zenith Electric Co. Ltd. regarding a resistance unit that did not meet specifications.
| Identifier | ExFiles\Box 163\6\ img299 | |
| Date | 14th January 1936 | |
| CONTRACTORS TO H.M. ADMIRALTY, WAR OFFICE, AIR MINISTRY, POST OFFICE, L.C.C. etc. Telegrams: VOLTAOHM, WILLROAD, LONDON. VOLTAOHM PHONE LONDON. Codes: LIEBERS 5. LETTER A.B.C. 5TH EDITION. Telephone: WILLESDEN. 4087-4088. THE ZENITH ELECTRIC Co., LTD. DIRECTORS: C. T. LEHMANN, J.{Mr Johnson W.M.} R.{Sir Henry Royce} LEHMANN, B.A. CANTAB., G.{Mr Griffiths - Chief Accountant / Mr Gnapp} P. HARRIS, AND SECRETARY. MANAGING DIRECTOR L. F.{Mr Friese} FOGARTY, M.I.E.E. Zenith Works. VILLIERS ROAD WILLLESDEN GREEN LONDON, N.W.2. REGISTERED OFFICES: 28, MONUMENT STREET, LONDON. E.C.3. Your Ref. Roy{Sir Henry Royce}/CGS/13/MUB. 14th January 1936. Our Ref. BFF/NS{Norman Scott} Messrs. Rolls-Royce Ltd., D E R B Y. Dear Sirs, We thank you for your letter of the 13th inst., and regret that the type "Y.10" Resistance Unit supplied against your order No. 97720 does not fulfil your requirements. We have considered your present specification and note that the resistance now required is to have a value of 200,000 ohms to carry currents up to 25 milliamperes for short periods. We think your present requirements would be met to the best degree, by the employment of our latest type "S.E" wire-wound embedded resistance units. Unfortunately, the largest size, namely, our type "S.E.4", having an overall length of 8 1/2" and a diameter of 1 5/8", can only be wound to a maximum value of 100,000 ohms, for complete reliability, and it would therefore need two of these units connected in series to provide the necessary ohmic value. These two units would be capable of dissipating up to a total of 160 watts for continuous operation. These units employ a single layer winding, in which it is difficult to remove the residual inductance, but the actual figure for the inductance does not, as a rule, exceed a few Micro-Henries, the errors from this Handwritten notes: Top right corner: -6016. Center: WST Right side: R-S Comment please Left margin: Hs{Lord Ernest Hives - Chair}/Wst | ||