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).
Dynamo testing conditions, specifically hot output curves, battery voltages, and variations in components from suppliers.
| Identifier | ExFiles\Box 36\4\ scan 065 | |
| Date | 29th May 1920 | |
| R.R. 199 (250T) (SD676 19-7-17) MP180805 Contd. -3- EFCl/T29.5.20. curve, and the dynamo is not allowed to run at a moment more than is necessary in order not to allow it to heat up appreciably. Our standard condition for the hot put-put curve is the maximum temperature the dynamo will reach when running continuously at maximum output. This curve was taken immediately after a heating test of the dynamo and it is considered that on the car, owing to the enclosed position, the dynamo willat least be as hot as this after running continuously, and that therefore the curve for this hot condition is representative of the performance we may expect of the machine in service. In regard to (2), we aim at keeping the block of batteries used for the purpose of dynamo tests in as nearly as possible the same condition so that it shows 12.4 volts on open circuit, after standing all night and 13.6 volts on open circuit immediately after charging. These are the two voltages we aim at in determining the balancing speeds of the dynamo, hot and cold. It will be noted that on the curves now presented, the operating votage is round about 14%, except for thehot curve for the E.575, for which it is round about 15, with the consequence that the output curve is a shade higher than it would have been if the voltage had been lower. In regard to (3), we have noticed that the dynamos come in from Messrs. Lucas with slightly varying settings of the control brush and that, although the balancing speeds may be very nearly the same, the outputs of the machines at Contd. | ||