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).
Continued discussion on dynamo performance, hot out-put curves, and battery conditions.
| Identifier | WestWitteringFiles\D\May1920\ Scan77 | |
| Date | 29th May 1920 | |
| Contd. -3- EFCl/T29.5.20. decent curve, and the dynamo is not allowed to run a moment more than is necessary in order not to allow it to heat up appreciably. Our standard condition for the hot out-put curve is the maximum temperature the dynamo will reach when running continuously at maximum out-put. 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 will at 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 voltage is round about 14, except for the hot curve for the E.575, for which it is round about 15, with the consequence that the out-put 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 R.R. 235A (100 T) (S.G. 648. 19-2-20) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 2618 | ||