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).
Extract comparing two methods of coil construction and their respective advantages.
| Identifier | ExFiles\Box 61b\4\ scan0151 | |
| Date | 19th December 1927 | |
| X4275 Extract from EFC4/T19.12.27. (4654) No great technical advantage is shown on test, neither does there appear to be any reason in principle for an advantage, either from - (1) The reverse order of building a coil, e.g. with the secondary inside and H.T. on the core and primary outside. or (2) The nearly closed iron circuit. So far as we can judge, at any rate in the case of (1), it would appear to be a question largely of manufacturing convenience and cost, and to some extent a question of better heat dissipation. ---- The construction of the coil with the inside secondary and outside primary is such that the circuit is largely closed by the magnetic casing into which the coil is finally sealed; this being at low potential it appears that the two gaps between the core and this magnetic casing are sufficiently only for due insulation against the H.T. of the core. | ||