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).
Tests on a chemical leak for a standard gap, analyzing the variation of its conductance with temperature.
| Identifier | ExFiles\Box 37\1\ scan 145 | |
| Date | 8th March 1923 | |
| EFC. PB.83. March 8th 1923. X.430. CHEMICAL LEAK FOR STANDARD GAP. X.3199. During some tests on coils, in which the chemical leak was used, it was observed that under certain conditions of speed, voltage, and ballast resistance, a coil would spark regularly at the gap with the leak connected across. A little later, however, with exactly the same conditions, the results would be quite different. It was at first thought that this variation in the performance of a coil was due to the ballast heating up, but was proved not to be the case. As this form of leak was known to possess a negative temperature coefficient it was concluded that the conductance was appreciably affected by either use across the gap, or the temperature of the room. The latter was confirmed by wrapping a cold damp cloth round the outside of the leak for a few minutes when regular sparking was obtained with the same circuit conditions that previously almost extinguished the spark. The actual variation of conductance with temperature, and also the lagging of the temperature of the solution behind that of the room, can be seen from the following observations. These were obtained by measuring the resistance of the leak at intervals and noting at the same time the temperature on a thermometer close by.{R.W. Bailey - Chief Engineer} Temp. °C. Conductance micromhos. 14.0 4.2 14.0 4.0 13.0 3.8 12.5 3.7 13.0 3.6 14.0 3.7 14.1 3.8 14.7 3.9 15.0 4.1 15.7 4.4 16.0 4.9 16.0 5.2 16.3 5.3 Max. variation in temperature = 3.8° Max. variation in conductance = 1.7 mhs. micromhos Aver. variation in micromohos per °C = .447 At the same time the small wireless leak was tested, but was found to vary only from 1.5 to 1.6 micromhos for the same temperatures. CAD | ||