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).
The failure of an old ignition coil, tracing the fault to varnish on the secondary winding.
| Identifier | ExFiles\Box 69\1\ scan0087 | |
| Date | 13th May 1928 | |
| EFC. WC.107. 13.5.28. IGNITION COILS. We have had a failure recently on one of the old std. coils PR2 (22 SWG. primary). This coil has done a considerable mileage on a chassis and has also been used extensively in the laboratory. The failure gave symptoms of a weakness in the secondary winding due to the presence of a high resistance leak when running. We unwound the coil and discovered that the ends of each secondary layer were discoloured and corroded, being still wet with varnish in places. This was more noticeable in the top layers, although in the bottom layers the wire in places was in as poor condition. We hope that the Production Dept. have discarded the use of varnish on the secondary winding. EFC/H.E.West. | ||