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).
Experiments on plain coil ignition and the effect of passing high tension cable through iron and copper tubes.
| Identifier | ExFiles\Box 61b\4\ scan0197 | |
| Date | 14th November 1919 | |
| (To R). V4119 Extract from EFCl/T14.11.19. RE EXPERIMENTS ON PLAIN COIL IGNITION. We have made a number of bench experiments on battery ignition which we record below :- 2. Effect of passing high tension cable through iron and copper tubes of similar dimensions. Particulars of tests made by us as to whether there is any difference between the use of am magnetic and non-magnetic metallic tube through which the high tension wire has to pass were as follows :- Coil. R.R. Standard. Running current reduced from normal (.92) to .87 a.p. by insertion of resistance. Spark Gap. Special adjustable spark gap with platinum points. Gap in each case adjusted to max. distance which would allow of regular sparking. H.T.Cable. Length 6 ft. dia. over insulation .625" dia. of core .075". core consisting of 30/30's aluminium flex. Iron Tube. Length 5 ft. outside dia. .750". thickness .062" Copper Tube. Dimensions the same as iron tube. Tube. Length of gap for regular sparking Tube insulated. Tube earthed. None. (cable straight). .210" --- Copper. .205" .035" Iron. .210" .035" It will be seen from the above table that provided the tube is insulated, passing the high tension wire through it makes no appreciable difference to the length of spark obtained, its capacity in this case being a negligible quantity. Contd. | ||