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).
Product specification for Insulating Compound M.R. 695 from The Insulating & Waterproofing Compounds Company.
| Identifier | ExFiles\Box 24\2\ Scan175 | |
| Date | 21th September 1921 guessed | |
| The Insulating & Waterproofing Compounds Company (J.{Mr Johnson W.M.} HENDERSON, D Sc. M.I.E.E.) 99, CURTAIN ROAD, LONDON, E.C. INSULATING COMPOUND M.R. 695. (As supplied to H.M. Government). This Compound is a liquid of very high Dielectric strength and Insulating properties, for the Impregnation of Textile Fabrics such as Silk, Linen, Cotton, Paper, etc., used in the manufacture of Insulating Cloths, Silks, Tapes and Condenser Dielectrics. The Compound does not contain any Rubber, Celluloid, Nitro-cellulose, Pyroxylene or spirit dissolved substances, but has an entirely oil basis; it is therefore non-injurious to the copper conductor and insulating fabric. Further, it will withstand any temperature to which the fabric may be subjected and still remain perfectly flexible, and does not crack or become hard and brittle when stoved. M.R. 695 has the property of thoroughly impregnating the material to which it is applied, and may either be air dried or stoved. In the latter case the temperature suggested is 200-212 degrees Fah., but it will withstand a far higher temperature than any fabric to which it is likely to be applied. The final dry surface is bright and smooth so does not require a finishing coat of varnish. The dielectric strength of this Compound is exceedingly high, National Physical Laboratory tests giving an average breakdown pressure of 20,000 volts per mm. for impregnated silk, whilst for condenser paper average values of 70,000 volts per mm. are obtained. Apart from its Insulating qualities the Compound possesses remarkable Waterproofing Properties, which render it particularly valuable in the case of electrical apparatus, such as dynamos and motors, liable to exposure to the weather. The consistent reliability of M.R. 695 is guaranteed by the manufacture being under the direct personal supervision of an electrical expert. | ||