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).
Page 2 of a letter from American Bosch Magneto Corporation regarding condenser specifications and testing.
| Identifier | ExFiles\Box 34\1\ Scan291 | |
| Date | 21th November 1921 guessed | |
| -2- Contd. mica condenser without completely destroying its effectiveness. A leaky condenser is, of course, equivalent to a capacity in parallel with the leakage resistance. This leakage resistance is also a function of the moisture in the condenser. Our wound condensers are dried in a vacuumoven before baking and assembling. The insulation resistance is then increased to approximately ten times the value specified for our test. It is possible that the condensers which you tested were not made in this way. We note that your tests call for a condenser which has a capacity between the limits of .21 and 26 microfarads. Our tests call for .3 mf. or above. As a matter of fact, none of our condensers run above .35 mf. although we do not consider that this is too great for satisfactory operation. Between .3 mf. and .4 mf. is satisfactory. As you know, the low melting wax which gave trouble at the scaled opening in the condenser has been replaced with a max which does not run at 200°F.{Mr Friese} Yours truly, AMERICAN BOSCH MAGNETO CORPORATION (Sgd) L. F.{Mr Friese} Curtis, Research Engineer. | ||