Electrical machines

Claim 1

IN A ELECTRICAL MACHINE, A COIL CONSISTS OF A PLURALITY OF CONDUCTOR BARS MOUNTED IN SLOTS IN THE MAGNETIC CIRCUIT OF THE MACHINE, EACH CONDUCTOR BAR COMPRISING A PLURALITY OF SMALL DIAMETER WIRES, OF SUBSTANTIALLY PURE METAL OR ALLOY, TWISTED TOGETHER TO FORM A SINGLE ASSEMBLY OF GENERALLY CIRCULAR CROSS-SECTION WITH EACH WIRE OCCUPYING VARIOUS DIFFERENT POSITIONS WITHIN SAID BAR ALONG ITS LENGTH, A FIRST INSULATOR ADAPTED PRIMARILY TO ELECTRICALLY INSULATE THE INDIVIDUAL WIRES FROM EACH OTHER, A SECOND INSULATOR, PRIMARILY A SUPERIOR THERMAL INSULATOR, SURROUNDING SAID BAR, PASSAGES EXTENDING ALONG THE BAR ADJACENT SAID ASSEMBLY IN SAID SECOND INSULATOR, FOR CIRCULATING A VERY LOW TEMPERATURE LIQUID COOLANT FOR COOLING SAID BAR, AND SUBSTANTIALLY REDUCING THE ELECTRICAL RESISTANCE THEREOF, A THIRD INSULATOR, PRIMARILY A SUPERIOR THERMAL INSULATOR, SURROUNDING SAID SECOND INSULATOR, AND A FOURTH INSULATOR SURROUNDING SAID THIRD INSULATOR AND ADAPTED PRIMARILY TO ELECTRICALLY INSULATE THE ASSEMBLY FROM THE MAGNETIC MATERIAL OF THE MACHINE, SAID SECOND AND THIRD INSULATORS HAVING VERY LOW COEFFICIENTS OF THERMAL CONDUCTIVITY TO MINIMIZE HEAT TRANSFER BETWEEN THE COOLANT AND SAID MAGNETIC MATERIAL OF THE MACHINE.