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).
390-hour test of Liberty Tungsten contact points in a battery ignition system.
| Identifier | WestWitteringFiles\F\January1921\ Scan33 | |
| Date | 21th January 1921 | |
| 88274. 21.1.21. A.A.40. EFC. --- X.2894 - LIBERTY TUNGSTEN CONTACT POINTS ON R.R. BATTERY IGNITION. A pair of tungsten contact points taken from Liberty ignition system and fitted to an R.R. standard distributor have run for 390 hours in conjunction with the experimental test of various H.T. sparking point materials. After the first 60 hours run, the points were discoloured a deep blue. A small projection had formed on the insulated (negative) point, and a corresponding pit in the other. The points showed considerable contact resistance (see report of 12.10.20 X.2894) which remained after they were cleaned up for the next 60 hours run. At the end of this time, the points were of a light yellow colour, a projection on the negative and a pit in the positive having formed as before. The points were now levelled off and allowed to complete the 390 hours of running, without attention. When finally removed, the earthed (positive) point was found to be almost black, but with a slight blue tinge, and pitted about the centre. The other point was of lighter colour with projections corresponding to the pitting of the positive. The surrounding metal surfaces were covered with a slight dull deposit. Contd. | ||