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 forwarding an inquiry from General Electric about standardizing single versus double contact base lamps for car wiring.
| Identifier | ExFiles\Box 168b\2\ img055 | |
| Date | 3rd August 1921 | |
| CC Mr. Henning Oy4 - G 3821 August 3, 1921 Mr. Claude Johnson, Managing Director, Rolls-Royce Ltd., London, England. Attention: Messrs. Royce & Clarke. Dear Sir: Re: Lamps [STAMPED: COPY] We have received the following letter from the National Lamp Works of the General Electric Co., and should be glad if you could supply us with a reply: "We notice in the specifications of miniature lamps for your car that you are using double contact bases for all your lamp positions." "The trend of standardization is towards single contact base lamps and it is expected that the number of cars using these lamps in all positions will be considerably increased this year; there were 42 makes of passenger cars last year using single contact base lamps in all positions, and 50 makes used them in all but one or two positions." "It has been our experience, as well as the experience of a great many car manufacturers, that it was much more difficult to locate grounds or short circuits with the two wire system. With the single wire system there is only one-half as much wiring and the number of places where a short circuit might occur is therefore considerably less. We note that in the S.A.E. Handbook with which you are no doubt familiar, that the "ground return" or one-wire system is recognized by giving three pages to the standards and recommended practice with this system, while only the definition of an "insulated return" or two-wire system is given. There may possibly be some angle to this problem to which we have not given due consideration, and if the single wire system is best for 99% of the cars, it seems very probable that it would be best for your car, and we are, therefore, interested in having your further comments on this question of standardization." Our impression is that the single wire system has the [Handwritten Notes] X-302 X 802 X 4087 X 3659 | ||