Transformer having novel multiple winding and support structure and method of making same

Abstract

Electrical apparatus includes electrical coil means formed of multiple turns of enamel-covered electrical wire axially mounted on a core of magnetic material in electromagnetic energy coupling relationship therewith, and a relatively flat flexible electrical cable containing a plurality of spaced parallel conductors extending between the cable ends contains a loop shaped portion extending about an axis of said core over an arcuate distance greater than 180 degrees. The method of adding a plurality of electrical windings to an electrical transformer of the type containing electrical coil means having a primary winding and at least one secondary winding, with said coil means having a central axis and a central passage coaxial with said axis; a core of magnetic material with said core having a portion extending through said central passage to support said coil means thereon, includes the step of forming into a loop extending about the axis of said coil an elongated flat cable of the type containing a plurality of spaced parallel electrical conductors insulated from one another.

What I claim is: 
     
       1. The electrical apparatus which comprises in combination: a metal container means having an opening and a lid for closing said opening;   a printed circuit board of electrically insulative base material containing a plurality of flat electrical conductors on at least one surface thereof;   a first set of spaced electrical terminals and a second set of spaced electrical terminals;   a core of magnetic material forming a magnetic circuit, said core including a center core leg and first and second outer core legs located on opposite sides of said center leg and extending parallel thereto to define therebetween a coil-receiving window;   electrical coil means having an axially extending central passage comprising a first primary winding containing a first multiple number of turns of enamel insulated electrical wire and at least one secondary winding comprising a second multiple number of turns, greater than said first multiple number, of enamel covered wire with said first winding overlying said second winding and said coil including an axially extending passage, said electrical coil means being mounted along the axis thereof on said center core leg with a clearance space between the outer periphery thereof and each of said outer core legs;   an elongate relatively flat cable means having a width substantially greater than the thickness thereof and containing at least three spaced parallel conductors extending between a first and second end of said cable means in electrical insulated relationship with one another;   said cable means extending in a loop about the periphery of said electrical coil means and over an arcuate distance therearound of greater than 180 degrees but less than 360 degrees and extending through the clearance space between said periphery of said coil means and at least one of said outer core legs;   means electrically and mechanically coupling said first end of said cable means to corresponding terminals in said first set of electrical terminal means on said printed circuit board;   and means electrically and mechanically coupling the conductors at said second end of said cable to corresponding ones of said electrical terminals in said second set of electrical terminal means; and wherein each of said core, coil means, cable and printed circuit board being disposed within said container means with said core and electrical coil means supported on a surface of said printed circuit board;   a plurality of electrical components mounted on said circuit board in an electrical circuit, and means, including said plurality of flat electrical conductors on said circuit board, adapted to electrically interconnect said electrical components in circuit with each of said primary and secondary winding of said coil means, and said first and second set of electrical terminal means; and electrically insulative potting material disposed within said container for encasing said circuit board, core, coil means, cable and electrical components therewithin.   
     
     
       2. The invention as defined in claim 1 wherein each of said first and second means for connecting said first and second cable ends to said respective first and second set of terminal means each comprise electrical connector means. 
     
     
       3. The invention as defined in claims 1 or 2 wherein said printed circuit board includes at least one electrical conductor extending between one terminal means of said first set of electrical terminals and one terminal means of said second set of electrical terminals. 
     
     
       4. The electrical apparatus which comprises in combination: a printed circuit board of electrically insulative base material containing a plurality of electrical conductors on at least one surface thereof;   a first set of spaced electrical terminals and a second set of spaced electrical terminals;   a core of magnetic material forming a magnetic circuit, said core including a center core leg and first and second outer core legs located on opposite sides of said center leg and axially extending parallel thereto to define therebetween a coil-receiving window;   electrical coil means having an axially extending central passage comprising a first primary winding containing a first multiple number of turns of enamel insulated electrical wire and at least one secondary winding comprising a second multiple number of turns of enamel covered wire with said first winding overlying said second winding, said electrical coil means being mounted along the axis thereof on said center core leg with a clearance space between the outer periphery thereof and each of said outer core legs;   an elongate relatively flat cable containing a plurality of spaced parallel conductors extending between a first and second end of said cable in electrical insulated relationship with one another;   said cable extending in a loop about the axis of one of said outer core legs over an arcuate distance between approximately 180 degrees and less than 360 degrees and extending through the clearance space between said periphery of said coil and said one outer core leg;   means electrically and mechanically coupling said first end of said cable to corresponding terminals in said first set of electrical terminal means on said printed circuit board;   and means electrically and mechanically coupling the conductors at said second end of said cable to corresponding ones of said electrical terminals in said second set of electrical terminal means;   a plurality of electrical components mounted on said circuit board in an electrical circuit; and means, including said plurality of flat electrical conductors on said circuit board, adapted to electrically interconnect said electrical components in circuit with each of said primary and secondary winding of said coil, and said first and second set of electrical terminal means.   
     
     
       5. The apparatus of claim 4 wherein the cable end extending through the clearance space further extends around the outer periphery of the coil over an arcuate distance of between approximately 180 degrees and less than 360 degrees, passes through the clearance space between the other outer core leg and the periphery of the coil means and extends about the axis of the other center core leg. 
     
     
       6. The apparatus of claim 5 wherein the core is oriented with respect to the printed circuit board so that the cable passes along the underside of the coil extends upward through the clearance spaces and over each of the outer core legs. 
     
     
       7. The electrical apparatus which comprises in combination: a printed circuit board of electrically insulative base material containing a plurality of flat electrical conductors on at least one surface thereof;   a first set of spaced electrical terminals and a second set of spaced electrical terminals;   a core of magnetic material forming a magnetic circuit, said core including a center core leg and first and second outer core legs located on opposite sides of said center leg and axially extending parallel thereto to define therebetween a coil-receiving window;   electrical coil means having an axially extending central passage comprising a first primary winding containing a first multiple number of turns of enamel insulated electrical wire and at least one secondary winding comprising a second multiple number of turns, greater than said first multiple number, of enamel covered wire with said first winding overlying said second winding and said coil including an axially extending passage, said electrical coil means being mounted along the axis thereof on said center core leg with a clearance space between the outer periphery thereof and each of said outer core legs;   an elongate relatively flat cable containing a plurality of spaced parallel conductors extending between a first and second end of said cable in electrical insulated relationship with one another;   said cable extending in a loop about the periphery of said electrical coil means and over an arcuate distance therearound of greater than 180 degrees but less than 360 degrees and extending through the clearance space between said periphery of said coil means and at least one of said outer core legs;   means electrically and mechanically coupling said first end of said cable means to corresponding terminals in said first set of electrical terminal means on said printed circuit board;   and means electrically and mechanically coupling the conductors at said second end of said cable to corresponding ones of said electrical terminals in said second set of electrical terminal means;   a plurality of electrical components mounted on said circuit board in an electrical circuit, and means, adapted to electrically interconnect said electrical components in circuit with each of said primary and secondary winding of said coil means, and said first and second set of electrical terminal means.   
     
     
       8. For use with an electrical transformer of the type including: a core of magnetic material including a center core leg and first and second outer core legs, and primary and secondary windings mounted about the core and respectively including a first and a second multiple number of turns of insulated electrically conductive wire, the primary winding being mounted around the center core leg,   a method for adding a plurality of low voltage electrical windings comprising the step of:   looping a flat cable containing a plurality of spaced parallely extending insulated electrical conductors about the peripheral surface of the primary winding through an arcuate distance in the range of approximately 180 degrees to less than 360 degrees.   
     
     
       9. For use with an electrical transformer of the type including: a core of magnetic material including a center core leg and first and second outer core legs, primary and secondary windings mounted about the core and respectively including a first and a second multiple number of turns of insulated electrically conductive wire, the primary winding being mounted around the center core leg,   a method for adding a plurality of fractional turn windings comprising the step of:   looping a flat cable containing a plurality of spaced parallely extending insulated electrical .[.conducts.]. .Iadd.conductors .Iaddend.about one of the outer core legs through an arcuate distance in the range of approximately 180 degrees to less than 360 degrees.   
     
     
       10. For use with a printed circuit board having a plurality of terminal members adapted to receive and secure the leads extending from electrical components, and an electrical transformer of the type including: a core of magnetic material including a center core leg and first and second outer core legs, on opposite sides of the center core leg at least a portion of each outer leg extending generally parallel to the center core leg,   primary and secondary windings mounted about the core and respectively including a first and a second multiple number of turns of insulated electrically conductive wire, the primary winding being mounted around the center core leg,   a method comprising the steps of:   looping a flat cable containing a plurality of spaced parallely extending insulated electrical conductors under the lower peripheral surface of the primary winding so that the cable passes between the winding periphery and the outer core legs;   folding the opposite ends of the cable over the respective outer core legs; and   securing the conductors at each cable end to respective terminals on the printed circuit board to form a number of additional single-turn windings about the core while simultaneously securing the transformer to the printed circuit board.   
     
     
       11. An improved electrical transformer of the type including: a core of magnetic material including a center core leg and first and second outer core legs, and   primary and secondary windings mounted about the core and respectively including a first and a second multiple number of turns of insulated electrical conductors, the primary winding being mounted around the center core leg,   wherein the improvement comprises:   a relatively flat multi-conductor cable extending in a loop about one of the outer core legs over an arcuate distance of approximately 180 degrees to less than 360 degrees; the ends of the conductors being adapted for electrical coupling external of the transformer to function as a plurality of fractional-turn windings.   
     
     
       12. The transformer as defined in claim 11 wherein said plurality of conductor in said flat cable is the number six. 
     
     
       13. The transformer of claim 11 wherein the cable further extends about the periphery of the primary winding over an arcuate distance of approximately 180 degrees to less than 360 degrees and thereafter extends in a loop about the other outer core leg over an arcuate distance of approximately 180 degrees to less than 360 degrees whereby the electrical coupling of the cable ends to electrical components additionally secures the transformer. 
     
     
       14. The invention as defined in claim 13 further comprising in combination: a flat printed circuit board;   and means securing said first and second cable ends to first and second locations on said printed circuit board to couple said electrical transformer to said circuit board. .Iadd.   
     
     
       15.  For use with an electrical transformer of the type including electrical coil means containing a primary winding and at least one secondary winding, said coil means having a central axis and a central passage co-axial with said axis; a core of magnetic material extending through the central passage to mount the coil about the core, a method for adding a plurality of fractional turn windings comprising the step of looping a flat cable containing a plurality of spaced parallely extending insulated electrical conductors about the coil means so that it curves through an arcuate distance in the range of approximately 180 degrees to less than 360 degrees. .Iaddend.