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).
Analysis of coil failures and potential remedies, discussing different materials and designs.
| Identifier | ExFiles\Box 49\5\ Scan020 | |
| Date | 17th July 1923 | |
| Contd. -2- EFC {E. Fowler Clarke - Electrical Engineer} 1/T17.7.23. a case in Redmanol material which so far has not given the least sign of failure in extreme conditions. This is the only coil that can at the moment be looked upon as an experimental coil, as the other 1/2" longer coils in the ordinary mouldensite cases have given suggestion of failure. Therefore, unless we take the deliberate step of here and now going to the 1/2" longer coil with a stabalite case, it appears that we still have remaining a possibility of failure. Therefore, in answer to EP {G. Eric Platford - Chief Quality Engineer} 's queries :- (1) The cause of the trouble in two cases appears to be the known fault of the 40/50 coils of insufficient insulation of the primary winding, due to the smallness of the coil as originally arranged, and therefore the desirability of a six-layer primary from the point of view of reasonable electrical efficiency and reasonably low sustained current on contact. (2) Apparently there is no simple remedy. Probably (3) the production of 1/2" longer four layer primary coils with stabalite cases would remedy the trouble. EFC. {E. Fowler Clarke - Electrical Engineer} | ||