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).
Further tests of two sets of tungsten contact points supplied by the Fansteel Co.
| Identifier | WestWitteringFiles\G\August1921\ Scan57 | |
| Date | 18th August 1921 | |
| EFC. AB.18 X.2894 - FURTHER TESTS OF TUNGSTEN CONTACT POINTS. Two further sets of tungsten points by the Fansteel Co. have been tested; one (AD) using a condenser with an earthing terminal, and the other (AE) with the points arranged to work with a scrubbing action. With the former set, the battery positive lead was connected directly to the earthing terminal of the condenser, the arrangement being otherwise standard. After 40 hours running, during which there was considerable sparking at the contacts and missing at the spark gaps, the points were showing a resistance of about 1 ohm. On removal they were found to be deeply dis-coloured and scaled, in the usual way, though the faces were still fairly flat, owing to the short time of running. Further running seemed unnecessary. The second set of points, was arranged with the tip of the blade bent forward about 30°, and the screw swivelled round to face it, so that the contact surfaces were at 60° with the line of motion instead of 90°. This produced a rubbing action which could be distinctly seen on moving the distributor slowly. After running for about 50 hours there was bad misfiring at the spark gaps. The run was continued Contd. R.R. 235a (100 T) (S.H. 159 11-8-20) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 2800 | ||