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).
Technical memo proposing the use of a Lucas A400 dynamo for charging at very low speeds.
Identifier | ExFiles\Box 36\4\ scan 181 | |
Date | 4th January 1921 | |
X 30746 EFC1/ATS.1.21. x3076a/1 RE DENSHAW & SORABJEE. Dynamo for charging at very low speeds. With reference to Sales' note Db{Donald Bastow - Suspensions}18/MH{M. Huckerby}4.1.21, herewith The only suggestion we can put forward for a dynamo to operate at very low speeds is to make use of the Lucas A400 type 40 lb dynamo. Of this Messrs Lucas have made us up four machines at different times, three of which we have in the Experimental Dept. One of these could be applied to the standard electrical system without any other alteration. A suspension for this dynamo has been designed. The standard E575 dynamo puts up cold a voltage of 12.4 at 610 r.p.m. and hot it puts up a voltage of 13.6 at 725 r.p.m. This is the extreme speed range of cutting in points, which, with our present drive ratio of 1.565 corresponds to a range in miles per hour of 11.7 to 13.9. If the Lucas A400 were used with a drive ratio of 1.4 : 1, which is that corresponding to the pulley we should propose to fit to this machine; then since the corresponding speed range for this machine is 330 to 390 r.p.m. the cutting in speed range in miles per hour on the road would be 7.1 to 8.4. This would probably be quite as low as Messrs. Dinshaw & Sorabjee require. The output of this machine is rather more than with standard Lucas E575, the maximum current of the machine in the hot condition attaining a value of 12 at about 1100 r.p.m. Copies handed to B/C. EFC. | ||