Thermally conductive potting compositions

Claim 1

IN AN ELECTRICAL MACHINE INCLUDING A ROTOR, A STATOR COMPRISING A PLURALITY OF COILS HAVING END TURNS WHICH TEND TO DEVELOP HEAT WHEN THE MACHINE IS OPERATED, AND A COIL-ENCLOSING METALLIC JACKET ADAPTED FOR THE PASSAGE THERETHROUGH OF A COOLANT, THE IMPROVEMENT WHICH COMPRISES EMBEDDING AT LEAST SAID COIL END TURNS, WITHIN SAID METALLIC JACKET, IN SOLID INSULATION COMPRISING A HEATHARDENED RESINOUS COMPOSITION ADAPTED TO CONDUCT THERETHROUGH HEAT DEVELOPED BY SAID COIL END TURNS, DURING OPERATION OF SAID MACHINE, TO SAID METALLIC JACKET, SAID RESINOUS COMPOSITION BEING AN ADMIXTURE COMPRISING (A) FROM 20% TO 40% BY WEIGHT OF A MIXTURE COMPRISED OF (A) FROM 40% TO 15% BY WEIGHT, BASED ON THE WEIGHT OF THE RESIN, OF A SILOXANE HAVIN THE FORMULA FI-01 WHEREIN R REPRESENTS A MONOVALENT ORGANIC RADICAL SELECTED FROM THE GROUP CONSISTING OF ALKYL RADICALS HAVING NOT MORE THAN 4 CARBON ATOMS AND PHENYL, TOLYL, AND XYLYL RADICALS, R1 REPRESENTS A MONOVALENT ORGANIC RADICAL SELECTED FROM THE GROUP CONSISTING OF METHYL AND VINYL GROUPS, AND N IS AT LEAST TWO AND HAS AN AVERAGE VALUE OF FROM 2 TO 10, THERE BEING AT LEAST 2 METHYL GROUP PER MOLECULE, SAID SILOXANE HAVING A VISCOSITY NOT EXCEEDING 1 POISE AT 25*C. AND (B) FROM 60% TO 85% BY WEIGHT, BASED ON THE WEIGHT OF RESIN, OF A HYDOCARBON SUBSTITUTED SILOXANE HAVING A VISCOSITY OF SUBSTANTIALLY MORE THAN 1 POISE AND HAVING ABOUT TWO HYDROCARBON GROUPS PER SILICON ATOM ATTACHED TO SILICON BY C TOSI BONDS, THE SAID (B) SILOXANE HAVING AT LEAST ONE ETHYLENIC GROUP PER MOLECULE ATTACHED DIRECTLY TO SILICON BY A C TO SI BOND, SAID ETHYLENIC GROUP BEING SELECTED FROM THE GROUP CONSISTING OF VINYL, ALLYL, AND METHALLYL RADICALS AND AT LEAST 50% OF