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 discussion on condenser design, comparing materials like twin paper and mica, and analysing capacity and efficiency.
| Identifier | WestWitteringFiles\H\November1921\ Scan27 | |
| Date | 10th December 1930 | |
| Contd. -2- The difficulty in the first case is that only a limited mechanical pressure can be applied to the plates without affecting breakdown, and this limits materially the capacity which can be got in a given space. So far as we know, we can only obtain the twin paper as used by U.S.A. Bosch from America, and it is very doubtful if rolls can be obtained in the width of strip we require, this being less than that used on the Bosch condenser, as the depth we have provided for the Goshawk condenser is rather less than that of the Bosch. Regarding mica condensers, our ideal case as you will remember was taken with mica thickness .0015" (this being the thickness of foil which we are using in our expts) uniformly, foils of .0005" uniformly, and the inductivity of mica 6.7. We find the maximum possible capacity per useful cubic inch of condenser to be .5 mf. This result we call 100%, and we think that this space efficiency can be obtained with the necessary experience in condensers which would stand our 450 volt (R.M.S. A.C.) test. We have, in a plate condenser of the Goshawk type, obtained relative efficiency of 80% of this, which, since the useful capacity available is .5 cubic inch, gives an actual condenser capacity of .20, but this result has been obtained on lines which are not considered by the Production Engineers to be possible on production. Since we would like to see the minimum capacity Contd. | ||