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 Joseph Lucas Ltd. discussing the selection of a dynamo for a post-war car.
| Identifier | ExFiles\Box 61\2\ scan0108 | |
| Date | 28th November 1918 | |
| COPY CLB/GD Joseph Lucas Ltd., Great King Street, Birmingham. 28th Nov. 1918. Messrs. Rolls-Royce, Ltd., Nightingale Road, Derby. Dear Sirs, Re Dynamo for Post- War Car. With further reference to our dynamo No.575, drawing of which we recently sent you, we beg to advise you that we have again considered the question of making this an 8 amperes Machine, providing a very low cutting - in speed, and we think that it will be necessary to avoid running such a machine at high speeds, that is to say, it is not desirable to run it above 2,000 r.p.m. In view of this, and the fact that it is likely to run rather hot, we think that the Dynamo No. E.585 would to give 12 amperes when warm and a current speed curve when cold, according to Dr'g No. L.499/4 enclosed herewith, will give a satisfactory voltage output for your requirements. You will see from the curve that a peak output is obtained at about 1,300 r.p.m. and the output decreases to 11 amperes between that speed and 3,600 r.p.m. Perhaps you will be good enough to examine this Curve and let us know whether you think it will be satisfactory; if so, the writer would like to visit you and discuss the question of switchbox and lamps. In case you are not is possession of a current speed curve of our pre-war type dynamo No.E.60, we are enclosing copy of same herewith. Yours faithfully, Joseph Lucas Limited (Electrical Dept) (Sgd) C.J. Breedon, Manager and Chief Engineer. For curves see X.3014 | ||