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).
Test results and general inferences from testing various coil cases under different temperature conditions.
| Identifier | ExFiles\Box 69\1\ scan0037 | |
| Date | 16th September 1926 guessed | |
| -3- drawn between readings indicates that the case was allowed to rest cool down in the interval. Otherwise it was maintained hot for about an hour before repeating the test :- Coil cases. | 1 | 2 | 3 | 4 | 5 | 6 | 7 | Off car. | |---|---|---|---|---|---|---|---| | + 1620 | 2950 | 2100 | 2320 | 1970 | 1200 | 2600 | 280 | | 3160 | 1400 | 2800 | 1265 | 1760 | 1900 | 1400 | 210 | | to | 980 | 1340 | 1125 | 845 | 700 | 1400 | 140 | | 1760 | | 775 | 700 | 420 | 700 | 985 | 140 | | 2100 | | | 1760 | | 420 | 10500| | | 1050 | | | 1050 | | 420 | 915 | | | 1125 | | | 910 | | | | | | 1270 | | | 350 | | | | | | 1200 | | | 280 | | | | | + shewed higher figure on switching on, and sank to lower in a minute or so repeatedly. The top line of (micro-ampere) readings gives the 100°C results of the previous table. All readings are for 2400 R.M.S. A.C. test volts. ------ General Inferences. The tests on the redmanol coil cases and on some of the sheet material all concur that increased leakage accompanies increased temperature. The stabalite case remained almost leakless, however, right up to the full temperature. (It became somewhat softened at 100°C). The cases and sheet material tend to shew, but not quite consistently, that repeated heating and cooling improves the insulation and this is particularly confirmed by the coil case taken from a car, which gave the best result of any. | ||