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).
Ignition coil failures during bench tests, identifying the cause as insulation breakdown.
| Identifier | ExFiles\Box 69\1\ scan0175 | |
| Date | 29th December 1928 | |
| EFC. WD.{Mr Wood/Mr Whitehead}23. COPY 29.12.28. IGNITION COIL FAILURES We have had two failures recently in the lab. of standard (22 SWG primary) ignition coils during certain bench tests. These coils were running during test under rather abnormal conditions e.g. discharging on a 8.5 mm. third point spark gap in air, and consequently any weakness in the insulation was readily revealed. The amount of running was only very small before failure occurred in each case under these conditions. had Upon unwinding each coil we found that the same trouble occurred in each coil, the trouble being due from the local evidence to the secondary insulation breaking down on the first two or three layers. The breakdown had occurred at a spot on the layer where the secondary wire had ridden over a lump in the insulation of the primary cased by the unevenly finished primary. See sketch EFC/H.E.West. | ||