Main field coil for railway traction motor

Claim 2

A coil assembly including a first, second and third winding, said first and second windings each having a first terminal adapted to be connected to a source of power and a second terminal connected to the ends of said third winding, said third winding having an outer peripheral dimension that is substantially equal to the inner peripheral dimensions of said first and second windings, said first and second windings encircling said third winding and having corresponding surfaces adjacent each other whereby said first terminals extend outwardly from said coil and are positioned intermediate the upper and lower surfaces of said coil.

Claim 3

A coil assembly as defined by claim 1 wherein said second terminals of said first and second winding are brazed to said ends of said third winding whereby said three windings are electrically connected in series.

Claim 4

A coil assembly as defined by claim 1 wherein the sum of the number of turns in said first and second windings equals the total number of turns is said third winding.

Claim 5

A coil assembly as defined by claim 1 wherein said windings are formed from copper straps of substantially rectangular cross section and wherein the surfaces of said windings are substantially rectangular.

Claim 6

A main field coil assembly for a traction motor, said coil being formed from flat copper strap of rectangular cross section and having two outer windings and an inner winding, each of said outer windings having a predetermined number of turns and said inner winding having a number of turns equal to the sum of the turns of said outer windings whereby said inner winding has substantially twice the depth of either of said outer windings, each of said outer windings having first and second terminals with said first terminals extending outwardly beyond the periphery of said outer windings and being adapteD to be connected to a source of electrical power, said inner winding having an upper and a lower terminal, means electrically connecting one of said second terminals to said upper terminal of said inner winding and means connecting said other of said second terminals to said lower terminal of said inner windings such that said first terminals are positioned intermediate the surfaces of said assembly.

Claim 7

A main field coil assembly for a traction motor, said coil being formed from flat copper strap of rectangular cross section and having two outer windings and an inner winding, each of said outer windings having a predetermined number of turns and said inner winding having a number of turns equal to the sum of the turns of said outer windings whereby said inner winding has substantially twice the depth of either of said outer windings, each of said outer windings having first and second terminals with said first terminals extending outwardly beyond the periphery of said outer windings and being adapteD to be connected to a source of electrical power, said inner winding having an upper and a lower terminal, means electrically connecting one of said second terminals to said upper terminal of said inner winding and means connecting said other of said second terminals to said lower terminal of said inner windings such that said first terminals are positioned intermediate the surfaces of said assembly.

Claim 10

A method for manufacturing a coil assembly as described in claim 6 wherein said last two steps of electrically connecting said coils comprise the brazing of said ends of said first and second second coils to the ends of said third coil.