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 from GRAY & DAVIS Inc. discussing the use of enamel wire for a magnet coil.
| Identifier | ExFiles\Box 24\2\ Scan151 | |
| Date | 25th March 1921 | |
| X1109 GRAY & DAVIS Inc. March 25, 1921. Rolls-Royce of America, Inc., Springfield, Mass. Attention: Mr. M.Olley, Engineer. X.1109 X 3331 X 3034 X3428 Gentlemen, Your letter of March 21st to Mr. L.W.Rosenthal, Vice President of the American Bosch Magneto Corportion, Springfield Massachusetts, along with blue prints Nos. F6712 and F7053, covering the assembly of magnet coil as used on your main switch and actuating box, has been turned over to the writer. I think that I can safely say that the standard practice of making such a coil in this country is as you have stated in the second case, namely the use of enamel wire and not impregnated. As I understand it, this coil will be used for very short intervals of time and temperature consequently low, therefore, I see absolutely no reason why plain enamel wire should not give good service, provided it is firmly wound and of good quality. My experience has not been to impregnate such a coil with any varnish but to tie a string on the outside and paint with an air drying varnish. As you possibly know that all enamel wires are nothing more or less than a flexible varnished on wire and the solvents in any varnish which may be used for impregnating would attach the enamel on the wire. This is consistent with the advice received from some of the biggest impregnating varnish manufacturers of this country. Hoping that this information may be of service to you, and assuring you that we are only too glad to co-operate in giving you the results of our experiencing in manufacturing electrical equipment for automobiles in this country, I remain, Yours very truly, GRAY & DAVIS INC. (Signed) L.B.Ehrlich, Chief Engineer. S' F' 223Y (20M) 1-21 H 169' (T-R-BU) U 2900 | ||