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).
Car running tests detailing dynamo output characteristics and switch operation.
| Identifier | ExFiles\Box 59\1\ Scan129 | |
| Date | 29th September 1926 | |
| -4- Contd. EMC 8908 recd for test and report on 29SEP26 ROLLS-ROYCE LIMITED DERBY Car running. In a warmed up condition (engine 80°C) (1) Switch operated at 15.8 volts. Output reduced from 7.0 to 4.8 amperes (Not on peak output). (2) After further running (engine 85°C) dash about 30° by touch), switch operated at 16.1 volts. Output reduced from 10.0 to 5.0 amperes. (3) After still further running (engine 85°C) Switch operated at 16.1 volts. Output reduced from 10.0 to 5.0 amperes. After operation of the switch, the voltage rose to a maximum of 16.6 volts and over a wide range of car speed varied only between 16.4 and 16.6 volts with corresponding outputs of 5.0 to 6.0 amperes, indicating the flat nature of the dynamo output char- acteristic with the field resistance inserted. The operation of the switch at all times and in all respects appeared to be quite definite and satisfactory." With regard to the slight uncertainty of operation referred to in the first report, there is no evidence of this being any disadvantage. Owing to the fact that the contacts are connected across by a relatively small resistance, there can be very little burning or wear at these contacts. It is true that with an auto-switch there is a slightly increased complication, but it would appear from what we have done so far that this adds a negligible amount to the unreliability of the system, and in other ways would be a distinct added advantage. There does not appear to be any difficulty in getting the device to act with sufficient | ||