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).
Performance and testing of American Bosch and Delco coils and condensers.
| Identifier | ExFiles\Box 35\6\ scan 126 | |
| Date | 11th June 1926 | |
| Oy2-E-61126 -2- June 11th 1926. 2. Coils. On American Bosch ignitions it is usual for contacts to run 10,000 miles without attention, and 25,000 miles without replacement. The Bosch coil like the Delco and other modern American coils has an almost continuous iron circuit, the primary wound on the outside of the secondary and no ballast resistance. The heat dissipation from the primary is sufficient to limit the temperature of the coil to a reasonable figure even with the engine at a standstill. We think that perhaps the long iron circuit avoids rapid alterations in the primary at break which may damage the contacts. We shall be pleased to send American Bosch or Delco coils for test, if you desire them. 3. On five 20 HP. condensers taken from Maintenence Dept. stock for replacement in service, we find a dielectric resistance varying between 1/4 and 7 megohms. Six American Bosch condensers similarly tested read 40 megohms to infinity. Yours very truly, (sgd) Maurice Olley. MO/E.{Mr Elliott - Chief Engineer} | ||