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 non-tracking properties and tests of Bakelite XM.1000 moulded material for distributor components.
| Identifier | ExFiles\Box 61\1\ scan0115 | |
| Date | 9th May 1930 | |
| X6011 Ry. from EFC. c. By/RD c. Sft{Mr Swift}/Mr.Brock. EFC2/ADL9.5.30. X6011 X.3513. BAKELITE XM.1000 MOULDED MATERIAL. X.5690. X.7690. The various tests of this material are now completed. It will be remembered that the particular advantage of this material was said to be its superior non tracking property as compared with other bakelite materials and that therefore it would be more suitable for a distributor rotor and a distributor head. A head and rotor and also a flat slab moulded in this material were therefore put through certain tests in which high tension discharges were made to traverse the surface of the insulation. In the case of the distributor head and rotor, this was done by running them on an ignition system with no high tension sparking taking place inside the head. After so running for 220 hours the head and rotor were removed for examination. The distributor head was practically unaffected. The rotor although deeply scored by the disruptive action of the H.T. discharges, had not apparently becomes carbonised at all, in any case not sufficiently to cause tracking to develop. In the tests made on the slab of material, high tension sparks of varying degrees of oscillating current density were tried as compared with the same effect on the bakelite X.616B material which, in this respect, is practically identical withthe standard Redmanol material at present used for distributor head and rotor. The general result of these tests is that, except for higher degrees of spark intensity ( i.e. amplitude of oscillating current) the tendency to track on the XM.1000 was considerably less than in the ordinary bakelite case. It is always possible to produce tracking on any bakelite material by a sufficient local heating effect of the spark passing across the surface i.e. if the spark is of a sufficient current density. | ||