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 bench testing of various materials for distributor sparking points in a battery ignition system.
| Identifier | ExFiles\Box 35\6\ scan 020 | |
| Date | 1st May 1923 | |
| THE.D.(W/S) 21/51. W5 M.M. (T/M) 2.500 5.23 EFC. A.A. 43. 88284. X.3309. - DISTRIBUTOR SPARKING POINTS OF VARIOUS MATERIALS FOR R.R. BATTERY IGNITION. During the bench tests of tungsten contact points on the R.R. battery ignition, a number of materials have been used for stationary distributor sparking points, and run with rotors with peripheries of the same materials for 60 ton70 hours each. There were respectively silver, tungsten, stainless steel, nichrome, nickel-brass and pure nickel. Silver. These points, after their 60 hours run, are much blackened. The metal has been partly burnt away where the spark has passed. The surrounding brass has also turned dull. The rotor is similarly discoloured but a small hump has formed at the extreme leading edge. The copper mounting block is much darkened. Tungsten. The points have a small spot at the centre, surrounded by a block ring, but have not been visibly burnt away. The rotor has darkened at the sparking edge, with slight signs of pitting. The copper mounting has dulled slightly and the heads of the clamping screws have blackened. Stainless Steel. The points are pitted and blackened at the spot where the spark has taken place. The remainder of the surface is quite bright, but the sorrounding brass is Contd. | ||