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 for static induction effects with high-tension wiring in a black fibre insulating tube on an EAC engine.
| Identifier | ExFiles\Box 61b\4\ scan0207 | |
| Date | 12th February 1925 | |
| EFC. WA.{Mr Wallis}109. Feb 12th 1925. STATIC INDUCTION EFFECTS WITH EAC. H.T. WIRING IN BLACK FIBRE INSULATING TUBE. Tests have now been carried out in connection with the above phenomenon, with the magneto and battery ignition wires bunched together in an insulated tube as used on the EAC. engine. 5 tests in all were completed. Firstly, with one of the ignition generators switched off and the other working, to observe the induced effect on the idle wires, and secondly, vice versa. The H.T. sparking was then observed with both ignitions working together, and lastly the effect of earthing one set of wires was observed in each case. With the battery ignition switched off and the magneto sparking, small induced sparks could be obtained from the ends of the battery ignition wires connected to the spark gaps, of magnitude as shewn in the table below. From this table it will be seen that the largest gap obtained corresponds to the longest length of wire in the tube (i.e. No.6 threads the whole length of the tube) the other spark lengths varying consistently as the length of wire in the tube. Spark Gap No. Max. gap allowing regular induced sparks to jump. 6. .025" 5. .020" 4. .020" 3. .016" 2. .012" 1. .008" INDUCED SPARKS ON B.I. GAPS (INSng. TUBE) Gap Nos. correspond to cylinder Nos. on engine. Contd. | ||