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).
Continued report on apparatus and methods for high voltage insulation testing.
| Identifier | ExFiles\Box 24\2\ Scan271 | |
| Date | 12th September 1926 guessed | |
| -3- Contd. the time to charge up will be considerably increased, but as the safe voltage of this condenser is smaller, the spark gap must be smaller. This condenser, however, acts as a very suitable reservoir for maintaining across the insulating material on test the smaller voltages which are required for insulation test purposes. The higher voltages (up to about 20,000 volts) must be obtained without the use of this condenser and our rectifying unit is so arranged in itself that it will just stand up (with no D.C. output) without breaking over anywhere, on the full peak potential which is obtainable from the trembler coil. The uses of this apparatus are for testing the D.C. insulation resistance of any kind of H.T. insulation, at a steadily applied D.C. voltage comparable with or considerably more than its working voltage. For instance, the H.T. wiring in position on engines may be tested, or the insulation resistance of bakelite coil cases at atmospheric temperatures, or when heated in an oven. A report of tests of this latter nature on up-to-date coil cases now going on production will follow. The supply to the rectifying unit can also be taken from the 20,000 volt H.T. transformer, but in that case it will be necessary to include a safety resistance in the supply to the plate terminal, as otherwise in the event of breakdown of the insulation tested, the valve would be damaged. A trembler coil has the advantage of itself acting as a | ||