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).
Output current measurements at 13.0 Volts, comparing performance with and without a temperature compensating device under cold and hot conditions.
| Identifier | ExFiles\Box 166\2\ img129 | |
| Date | 28th October 1937 | |
| -3- Output Current at 13.0 Volts. Cold. Specified. 14.0 to 16.5 amperes. Lucas unit without compensation. 10.8 " (Average for whole range of speed) Unit with compensation. 16.0 " " " " Output Current at 13.0 Volts. Hot. Specified. 15.0 to 18.5 amperes. Unit without compensation 16.7 " (Average) Unit with compensation. 11.5 " " The difference between, for example, the value 10.8 amperes cold, and the corresponding hot value of 16.7 amperes, due to heating up, is excessive, and indicates we think, undue internal heating of the shunt winding. The effect of the temperature compensating device, is shown in the drop from the value 16.0 amperes cold, to the corresponding value, hot, of 11.5 amperes. Repeated attempts have been made to reduce the amount of compensation, but this apparently, cannot be carried any further without weakening the unit mechanically. (c) Under day-running conditions, when the battery is fully charged, and the ignition and petrol pumps are the only load on the system, the battery charging current should not be more than about 3 amperes. Like the night-running load, this is subject to variation due to rise in temperature, and at present we have to accept a wider range of variation than we like. | ||