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).
Temperature measurement tests on two different types of coils (X and Y) under various conditions.
| Identifier | ExFiles\Box 69\1\ scan0123 | |
| Date | 6th July 1928 | |
| EFC3/T6.7.28. -2- Contd. any air space round the coil, or rather between the coil and the case. In this case one of the two coils, designated Y, was of the finer primary type, and one of the coarser or 22 S.W.G. primary (now again standard) type, designated X. The test consisted, as before, of :- (1) Temperature measurements of the windings by the increasing secondary resistance method, after working five hours with a 17.5 volt supply in conjunction with a standard distributor set to the make ratio of 345, running at 700 r.p.m. (2) Similar temperature measurements after 1 1/2 hours standing on contact with a 12 volt supply. In each case a standard double ballast resistance was used. We found the maximun temperatures attained to be :- Coil. Condition 1. Condition 2. Y 69°C. 65°C. X 52°C. 40°C. First comparing the temperatures attained by the finer primary coil Y with temperatures previously attained by these coils, in the same circumstances, the temperature attained standing on contact is of the same order of magnitude. The temperature attained after a five hours' run, however, may be considered to be a little less than the average result in the previous case. Further, as before, the temperature after the run is slightly greater than the temperature after being on contact. Now considering the result from the courser primary coil X, the temperatures attained are considerably lower in Contd. | ||