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).
Letter to the Managing Director suggesting improvements to electrical insulation materials to improve heat resistance and reduce costs.
| Identifier | ExFiles\Box 34\3\ Scan078 | |
| Date | 24th March 1921 | |
| x2641 OyB-G24.3.21. March 24, 1921. Mr. Claude Johnson, Managing Director, Rolls-Royce Ltd., London, England. Attention: Mr. Royce & Works Committee. Dear Sir:- X.1109 Re: Insulation. X.3716. X.3034. X.3428. X.2641. We wish to suggest for the attention of the Works Committee that the electrical insulation used on the car might be very considerably improved with a decrease in manufacturing costs. In several places on the car we use insulation which cannot be regarded as of a permanent nature. As an example, the Ebonite used on the terminals of the actuating box and the Micanite used in the base of the ballast resistance, which latter, we understand has given trouble through softening of the shellac when the ballast resistance heats up. In addition to this, we attempt in most places on the car to avoid making electrical contacts by pressure on the insulation, but at the same time we find that in the actuating box terminals and the contact at the base of the ballast resistance, we do make contact by pressure on the insulation, and in most of these cases the insulation is likely to become softened by the heat and is not of a nature to resist heat. We therefore wish to make the following suggestions :- (1) Ballast Resistance: Star contact F-7359 should be sweated to the bolt F-7347 and the insulating washers F-7343 and F-7344 and the bush F-7354 should be grade A Bakelite Dilecto made by the Continental Fibre Co. and used for switch bases which are subject to heat. The base of this material is asbestos paper. Also washers F-7345 and F-7893 should be of grade A Bakelite Dilecto. (2) Actuating Box: Insulating plates F-7052 and F-7051 and tube F-7050 changed from Ebonite to Bakelite Micarta (paper base) or Bakelite Dilecto, Grade XX (paper base). Contd. | ||