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).
Comparison of ampere output and voltage performance curves for a Bosch dynamo unit under hot and cold conditions.
| Identifier | WestWitteringFiles\J\January1923\ Scan8 | |
| Date | 18th January 1923 guessed | |
| Contd. -2- In both cases (c) and (d), the ampere output curve is quite steep and occurs at speeds very nearly as low as the two pole pre-War Bosch machine and one other machine tested, namely, Rotax AT.12. Open circuit operation of dynamo with controller in action. Please find attached photostat curves of the open circuit voltage performance of the Bosch dynamo unit, comprising dynamo, regulator and cutout. The voltage curves for both cold and hot conditions are given, the actual difference in controlled voltage being considerable. The small kinks in these voltage curves occur where the first part of the regulation (on the bottom contact) ceases, and the second begins, the second portion continuing to any speed at which the dynamo is run. Curves of the regulated field current are also shown. It will be noted that the control voltage in the hot condition appears rather higher than would be considered suitable for operating a small lamp load such as side and tail, where the amperes taken are not large enough to pull down the regulating voltage by means of the series coil. It does not appear to us that there is any advantage in the difference of the performance hot and cold, but that the difference in this hot and cold operation might suitably have been somewhat less, utilising a resistance of zero temperature coefficient in series with the shunt coil of the regulator. A number of volt-ampere characteristics of performance of the unit working on an external circuit | ||