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 performance test of Melin tungsten contact points after a 390-hour run.
| Identifier | ExFiles\Box 180\M1\6\ img015 | |
| Date | 19th September 1921 | |
| R.P. 283A (50 Td S R.{Sir Henry Royce} 986. 10-8-21) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 2928 COPY. 19th Sept. 1921. EFC. AB.24. X.2894 - TESTS OF MELIN TUNGSTEN CONTACT POINTS (A.H.). This set has performed better than most of the other sets of tungsten points, having run for 390 hours, mostly without sparking. At the end of the run, however, bad misfiring occurred, and there was a contact resistance of one ohm. A slight transfer of metal has taken place and both points are deeply discoloured. There is also a dull deposit on the surrounding surfaces. Of the three other sets received, one has the blade point cracked, another was handed to Mr. Coverley for adaption to scrubbing action for fitting to an experimental car and the last was handed to Col. Harker for the School car. The above test set of points does not appear to have run sufficiently well to warrant obtaining further sets, necessarily of this particular make, until a more general solution to the successful use of tungsten is found. Tests are proceeding, using augmented capacity, lower voltage, etc. Sgd. F.W.A. | ||