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 outlining the requirements and specifications for a car lighting dynamo.
| Identifier | ExFiles\Box 31\1\ Scan034 | |
| Date | 14th March 1919 | |
| X.1402. By5/P14.3.19. March, 14th 1919. Friday. The British Thomson Houston Co. Ltd., Lower Ford Street, COVENTRY. Dear Sirs, X.1268 DYNAMO FOR CAR LIGHTING. X.1402 Referring to your letter of the 13th inst., reference Engineering Department. APY/WS, signed by your Mr. Young, the particulars you require are as follows:- The maximum belting ratio we can allow for on the chassis is 1.5 to 1. In order to be quite sure that the lighting outfit is satisfactory for town and colonial work where considerable running is done at low speeds, it will be necessary for the dynamo to generator 10 amps at 750 revs of the dynamo. In addition to the above, we consider that the dynamo should be capable, when running at full speed of giving an output of 18 to 20 amps, in order that when the Starter Motor has been used and the lamps are full on there will be an excess of current over that required for the lamps to charge up the battery, even under these conditions. The system we prefer is a constant voltage scheme controlled by a Tyrrell regulator, with probably a series winding added to the regulator to limit the maximum output of the dynamo to the figure quoted above - this precaution being added merely to prevent belt slip. In regard to the weight of the dynamo to compare with existing systems, this should not exceed 35 lbs. Contd. K.R. 189 (250) (SD676 19-7-17) MLP6080S | ||