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).
Characteristics and results of an electrical insulation test system.
| Identifier | WestWitteringFiles\P\2July1926-September1926\ Scan163 | |
| Date | 16th September 1926 | |
| EFCL/T16.9.26. -2- Contd. The characteristics of the test system would be such that if the insulation stood up perfectly, i.e. no leakage current, the applied test D.C. voltage would reach this maximum figure, and this maximum applied voltage would fall somewhat from this figure by an amount which would be approximately proportional to the leakage current taken. We have no exact means, however, of saying just what the figure below this test voltage would be, corresponding to any particular leakage current observed in m.a. on the instrument, though we can say that the maximum amount taken off cannot much exceed 200 volts. It is to be observed that the recorded m.a. reading is a time average and is roughly speaking only about 1/3 of the m.a. passing through the leaky insulation at the time of application of the maximum voltage. The results of our tests comprise a statement of - (1) The material tested, (2) The thickness of the material, (3) The area of the test plates in opposition to one another on the two sets of the material, (4) The temperature, (5) The milliamperes observed. There is one group of these results for a maximum applied voltage of 3400 and a second for a maximum applied voltage of 1700. In some cases, particularly in the case of the coil cases, the tests have been repeated, because it has been found as a result of these tests that the leakages are by no means consistent at different times and seem to depend a good deal on previous temperature history. Contd. | ||