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).
On condenser testing procedures, discussing issues with 'Stickoline' varnish and potential alternatives.
| Identifier | WestWitteringFiles\C\August1919\ Scan30 | |
| Date | 1st August 1919 | |
| -2- EFC3/T1.8.19. R.R. 235 A (100 T. & S.F. 575, 16-4-19) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 2354. Contd. 1. Condenser built up in shop but not encased. 2. Tested for 30 minutes on alternating voltage of 200. 3. Tested for 10 minutes on alternating voltage of 350. 4. Capacity test at 200 alternating volts. Limits .19 m.f. to .23 m.f. 5. Fitted up in case. 6. Test 3 repeated. We have eight condensers which have passed steps 1,2,3,4, and are at present being fitted up in their cases, as 5. We are confident that all these will get through this routine and be available for fitting to chassis, and we are asking particularly for three of these to be completed and ready by 12 o'clock to-morrow. We do not consider that with condensers which have undergone these tests, which include two applications of 350 R.M.S. A.C. volts, we shall have any cause for anxiety. The condensers so far built have been made up with a varnish called "Stickoline", between the foils and the mica plates. We have found that condensers which have been built up dry and only had the varnish applied round the edge, stand up to the test very much better. We feel that this varnish, by searching out possible cracks in the mica, is largely the cause of breakdown. It is a thick varnish and we think that a varnish made of pure alchohol with the white shellac in place of the red, would give more satisfaction. We are, therefore, at the moment also experimenting on these lines of using different kinds of varnish, having noticed that in outside condensers, which stand these tests with ease, the varnish used Contd. | ||