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 and green lamp performance and adjustments on experimental cars.
| Identifier | ExFiles\Box 165\6\ img182 | |
| Date | 14th January 1929 guessed | |
| X5660 Extract from RJA2/C.4.1.29 (X7780) DYNAMO & GREEN LAMP. ON 18-EX IN FRANCE The car having finished its running here, we had had an opportunity of changing over the green lamp coil connection to terminal B in the distribution box and trimming up the cutout points before its being taken over by EP.{G. Eric Platford - Chief Quality Engineer} and CWB. It was noted that the lamp operated somewhat early (15.8 v) This together with the fact that it would not go off, on switching to the M & B position was explained to EP{G. Eric Platford - Chief Quality Engineer}; speedometer reading 10166. DYNAMO & GREEN LAMP ON 14-G4. The output of the dynamo on this car (M.5.R) proved to be inadequate for the running conditions obtaining. With the battery in an intermediate state of charge and the machine warm the peak by the chassis ammeter was not above 9.0 amperes (engine on magneto ignition). With headlamps on at high speeds there was a discharge of from 3 to 4 amperes and on a night run the battery ran right down, the other car having to be used as a pilot. On a daytime run we took the 25 voltmeter and found that the volts did not rise above 13.0 measured at the headlamp socket. The control brush was therefore retarded a considerable amount (about 5°) and this brought the output up to about 13.0 amperes peak (hot). On subsequent daytime runs the green lamp has functioned very satisfactorily. The lighting voltage (measured at the switchbox) was 16.7 volts and the maximum voltage reached by continuing charging was 17.0 volts. The operation is very consistent, the system voltage may rise somewhat higher under certain circumstances with the machine cold. Although the dynamo output may be too high for the dynamo and battery in ordinary circumstances, the green lamp indications combined with the high average running speeds obtaining should act as sufficient protection. Certainly the running conditions obtaining here call for dynamos of the H.O. type, early cutting in being of quite secondary importance and a fair charging rate at high speed desirable. | ||