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).
Component performance and failure conditions during a series of road tests at varying temperatures.
| Identifier | ExFiles\Box 166\1\ img103 | |
| Date | 14th July 1937 guessed | |
| -2- The second test consisted of running a short distance, 12 miles, and warming the air under the bonnet, without greatly warming the windings of the unit. In this case a cover temperature of 53°C. was reached, with an atmospheric temperature of 23°C. - 24°C. and no failure occurred. For the third test, the car was run for a distance of about 40 miles when failure occurred, and the ambient temperature at the cover was again 53°C. with an atmospheric temperature of 23°C. From this it would appear that the main factor in performance variation, is the heat produced in the unit itself." It may be perhaps that the major heating is coming from the series windings and not the shunt but no doubt you are able to determine this. The question of reduced temperature effect on the cutout should be treated as urgent in view of the fact that we are urging standardisation tests of the unit on all our cars in preference to the C.A.V. regulator. Yours faithfully, FOR ROLLS-ROYCE LIMITED. | ||