Rolls-Royce Archives
         « Prev  Box Series  Next »        

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).
Methods for the impregnation of electrical windings and other materials, comparing different techniques.

Identifier  ExFiles\Box 24\2\  Scan291
Date  19th March 1928 guessed
  
-4-

"Referring to the letter under the above heading in the "Correspondence" columns of the current issue of the Electrical Review, I am very pleased to note that Mr. Brown is in such complete agreement with me on the views expressed therein, viz. that good impregnation of electrical windings is impossible without a thorough drying-out in a vacuum, and subsequent impregnation under pressure.

In the article in question, I, of course, made no attempt to treat exhaustively the whole subject, methods of heating, etc. but I am glad to see that Mr. Brown advocates oil heating. This method of heat transmission is by no means the novelty that Mr. Brown appears to think it is, because over 22 patents have been taken out in this connection, and the M.A.X.E.I. Co. alone has put down over 200 installations of its oil-heated plant in various countries, including England (where the system is patented) since 1918.

The advantages of oil heating depend on the correct design of the apparatus, and the M.A.X.E.I. system possesses the following advantages besides those mentioned by Mr.Brown:-

The practically indefinite conservation of the first filling of oil, and this without a trace of oxidation.

Extremely practical and convenient method of filling up the heating circuit with oil.

Automatic compensation for the expansion of the oil when heated.

Entire absence of danger from fire.

Complete avoidance of local heating.

Again, the intricate processes involved in the impregnation of wood, cardboard, etc. with synthetic resin (which are patented in England by the M.A.X.E.I. Co.) were not touched on by me, as they are outside the scope of the article in question.

I may point out here, however, that two large factories have recently been put to work in France, and one in Italy, using the M.A.X.E.I. process under licence, for the impregnation of wood and cardboard articles with synthetic resin.

Referring to Mr. Brown's remarks about obtaining knowledge of the amount of moisture in the windings, the best method of knowing exactly when all the moisture has been extracted is by using a condenser as supplied on the M.A.X.E.I. plants, to condense the extracted vapour, and observe the flow of condensate; another method is to test the windings electrically.
  
  


Copyright Sustain 2025, All Rights Reserved.    whatever is rightly done, however humble, is noble
An unhandled error has occurred. Reload 🗙