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).
Tests on Goshawk ignition coil cases to determine their electrostatic and leakage effects under hot and cold conditions.
| Identifier | WestWitteringFiles\J\November1922\ Scan79 | |
| Date | 13th November 1922 | |
| EFC. 58. 13th Nov. 1922. X.4079 - TESTS ON GOSHAWK IGNITION COIL CASES. X.3513. In connection with the recent troubles experienced on the Goshawk ignition, some tests were made on various coil cases to determine their electrostatic and leakage effects both hot and cold. It was found that if a coil case were used as the dielectric of a condenser (first, by filling with acidulated water and later by lining with tin-foil for the inside electrode) using a tin-foil wrapping for the outer electrode a good capacity effect could be obtained, the spark brightening up considerably without reducing much in length. A similar effect could be produced using a disc of Elo laid on an earthed metal plate with the metal foil placed on it for the H.T. electrode. When heated, the capacity effects increased considerably, but on reaching 70 - 80°C large losses began to occur which reduced the spark length to about 2.0 mm. without intensifying the discharge. The effects with the foil lined cases are similar with the coils inside or working separately. Two cases in phenol materials were used for the tests one in Elo and the other in bakelite (American). All the effects were somewhat more pronounced with the Elo, than the bakelite, especially at the high temperatures. In order to show how much of the losses were due to leakage the cases were lined and covered with large tin-foils of about 100 sq.cms. each and connected through a | ||