Methods and apparatus for fusing electrical conductors

• US 5,300,753 A
• Filed: 06/25/1992
• Issued: 04/05/1994
• Est. Priority Date: 06/25/1992
• Status: Expired due to Term

• Current Assignee: ATOP SpA
• Original Assignee: Axis Usa, Inc.
• Inventors: Rossi, Alessandro
• Primary Examiner(s): Shaw, Clifford C.
• Application Number:
  US07/903,910
• Time in Patent Office: 649 Days
• Field of Search: 219/110, 219/86.51, 219/56.1, 219/56.21, 219/56.22, 219/87, 219/91.1, 219/91.21
• US Class Current: 219/110
• CPC Class Codes: B23K 11/252 using digital means

Abstract

Methods and apparatus for fusing together electrical conductors to a commutator are provided. A precise, timed, and controlled delivery of electric current to the fusing electrode of the fusing machine is achieved. A generic supply signal is converted into a precise and constant input signal through the use of monitoring and feedback techniques, which compare the current status of the physical and electrical phases of the fusing operation to various predetermined fusing profiles to determine the proper application of current to the fusing electrode.

Claims

1. Apparatus for fusing at least one armature wire and at least one piece of commutator material together, said apparatus, comprising:

a fusing member for applying force and varying heat to soften said commutator material to deform said commutator around said armature wire;

a grounding member;

means for moving said fusing member relative to said armature wire and said commutator material in order to cause said fusing member to contact and apply force to said commutator material thereby deforming said commutator material intimately around said armature wire;

means for controlling said means for moving said fusing member in accordance with a predetermined physical delivery function to control said applied force;

means for regulating a precise flow of current through said armature wire and said commutator material from said fusing member to said grounding member to generate said varying heat in said fusing member in accordance with a predetermined electrical delivery function to regulate said precise flow of current and thereby regulate the level of said varying heat so that said commutator material is softened and therefore, said deforming is precisely controlled, and so that insulation on a portion of said armature wire within said softened deformed commutator material is vaporized; and

means for synchronizing said means for controlling and said means for regulating in order to supply a precise varying level and quantity of heat from said fusing member to said armature wire and said commutator material at specific, predetermined time intervals, such that said regulating means is essentially instantaneously responsive to the short timings and different heating requirements which occur during fusing of said armature wire to said commutator material.

2. The apparatus defined in claim 1 wherein said means for regulating comprises:

a source of potential supplying a three-phase alternating current (AC) signal; and

a control circuit for converting said AC signal to a precise level of non-oscillating voltage.

3. The apparatus defined in claim 2 wherein said control circuit comprises:

a first full-wave rectifying bridge for rectifying said AC signal, said first rectifying bridge having an input connected to said source of potential and two output terminals;

a converter circuit for converting said rectified signal into a rectangular full-wave form signal, said converter circuit having two input terminals connected to the output terminals of said first rectifying bridge and two output terminals; and

a second full-wave rectifying bridge for rectifying said rectangular full-wave form signal into an output signal having a single polarity and essentially no ripple, said second rectifying bridge having two input terminals connected to said output terminals of said converter circuit and two output terminals being connected to said fusing member.

4. The apparatus defined in claim 3 wherein said converter circuit comprises:

a bridge circuit comprised of at least two transistor pair circuits, each transistor pair circuit being connected between said output terminals of said first rectifying bridge, and each transistor pair circuit having an output node which provides one of said output terminals of said converter circuit; and

a driver circuit which supplies a plurality of transistor trigger signals to said bridge circuit to control the operation of said bridge circuit such that said bridge circuit generates said rectangular full-wave form signal.

5. The apparatus defined in claim 4 wherein each of said transistor pair circuits comprise:

a pair of transistors, which provide a rectangular half-wave form signal, comprising first and second transistors, each transistor having a base uniquely connected to said driver circuit, a collector, and an emitter, said collector of said first transistor being connected to a first of said output terminals of said first rectifying bridge, said collector of said second transistor being connected to both said emitter of said first transistor and said output node, and said emitter of said second transistor being connected to a second of said output terminals of said first rectifying bridge.

6. The apparatus defined in claim 5 wherein said converter circuit further comprises:

a current feedback sensor for measuring said current component of said rectangular full-wave form signal; and

comparing circuit means for comparing said current component to a first predefined reference signal, said comparing circuit having an output connected to said driver circuit whereby said comparing circuit means provides error correction input signals to said driver circuit which cause said driver circuit to change said transistor trigger signals.

7. The apparatus defined in claim 6 wherein said converter circuit further comprises:

a voltage feedback sensor for measuring said voltage component of said rectangular full-wave form signal; and

said comparing circuit means for comparing said voltage component to a second predefined reference signal, said comparing circuit means having an output connected to said driver circuit whereby said comparing circuit means provides error correction input signals to said driver circuit which cause said driver circuit to change said transistor trigger signals.

8. The apparatus defined in claim 4 wherein said converter circuit further comprises:

a voltage feedback sensor for measuring said voltage component of said rectangular full-wave form signal; and

comparing circuit means for comparing said voltage component to a predefined reference signal, said comparing circuit means having an output connected to said driver circuit whereby said comparing circuit means provides error correction input signals to said driver circuit which cause said driver circuit to change said transistor trigger signals.

9. The apparatus defined in claim 4 wherein said converter circuit further comprises a transformer connected between said bridge circuit and said second full-wave rectifying bridge.

10. The apparatus defined in claim 9 wherein said means for regulating further comprises a transformer connected in series between said source of potential and said controlling circuit.

11. The apparatus defined in claim 1 wherein said means for controlling provides status signals corresponding to a status point within said predetermined fusing function.

12. The apparatus defined in claim 11 wherein said means for regulating provides feedback signals corresponding to said flow of current to said fusing member.

13. The apparatus defined in claim 12 wherein said means for synchronizing comprises:

means for comparing, which uses said status signals to determine a required level of said flow of current and compares said feedback signals to said required level of said flow of current to generate adjustment signals; and

means for applying said adjustment signals to said means for regulating in order to maintain said flow of current at said required level.

14. The apparatus defined in claim 13 wherein said means for regulating comprises:

a first full-wave rectifying bridge for rectifying an alternating current (AC) input signal, said first rectifying bridge having an input connected to a source of potential supplying a three-phase AC signal and two output terminals;

a bridge circuit comprised of at least two transistor pair circuits, each transistor pair circuit being connected between said output terminals of said first rectifying bridge, and each transistor pair circuit having an output node which provides an output terminal of said bridge circuit;

a driver circuit which supplies a plurality of transistor trigger signals to said bridge circuit to control the operation of said bridge circuit such that said bridge circuit generates a rectangular full-wave form signal; and

a second full-wave rectifying bridge for rectifying said rectangular full-wave form signal into an output signal having a single polarity and essentially no ripple, said second rectifying bridge having two input terminals connected to said output terminals of said bridge circuit and two output terminals being connected to said fusing member.

15. The apparatus defined in claim 14 wherein each of said transistor pair circuits comprise:

a pair of transistors, which provide a rectangular half-wave form signal, comprising first and second transistors, each transistor having a base uniquely connected to said driver circuit, a collector, and an emitter, said collector of said first transistor being connected to a first of said output terminals of said first rectifying bridge, said collector of said second transistor being connected to both said emitter of said first transistor and said output node, and said emitter of said second transistor being connected to a second of said output terminals of said first rectifying bridge.

16. The apparatus defined in claim 11 wherein said predetermined fusing function corresponds to a predetermined force function.

17. The apparatus defined in claim 16 wherein said means for controlling comprises:

a force sensor which measures said force of said fusing member on said plurality of conductors and generates a corresponding force signal; and

feedback means responsive to said force signal, said feedback means providing controlling signals to said means for moving said fusing member in order to conform to said predetermined force function.

18. The apparatus defined in claim 11 wherein said predetermined fusing function corresponds to a predetermined displacement function.

19. The apparatus defined in claim 18 wherein said means for controlling comprises:

a displacement sensor which measures displacement of said fusing member from a predetermined location and generates a corresponding displacement signal; and

feedback means responsive to said displacement signal, said feedback means providing controlling signals to said means for moving said fusing member in order to conform to said predetermined displacement function.

20. The apparatus defined in claim 1 wherein said predetermined physical function is based on force.

21. The apparatus defined in claim 1 wherein said predetermined physical function is based on displacement.

36. The method defined in claim 20 wherein said predetermined physical function is based on force.

37. The method defined in claim 20 wherein said predetermined physical function is based on displacement.

22. The method of using a fusing member to use together at least one armature wire and at least one piece of commutator material, the method comprising the steps of:

moving said fusing member relative to said armature wire and said commutator material in order to cause said fusing member to contact and apply force to said commutator material thereby deforming said commutator material intimately around said armature wire;

controlling the movement of said fusing member in accordance with a predetermined physical delivery function to control said applied force;

regulating a precise flow of current through said armature wire and said commutator material from said fusing member to a grounding member to generate varying heat in said fusing member in accordance with a predetermined electrical delivery function to regulate said precise flow of current and thereby regulate the level of said varying heat so that said commutator material is softened and therefore, said deforming is precisely controlled, and so that insulation on a portion of said armature wire within said softened deformed commutator material is vaporized; and

synchronizing the control of movement of said fusing member and the regulation of said flow of current in order to supply a precise varying level and quantity of heat from said fusing member to said armature wire and said commutator material at specific, predetermined time intervals, such that said step of regulating is essentially instantaneously responsive to the short timings and different heating requirements which occur during fusing of said armature wire to said commutator material.

23. The method defined in claim 22 wherein the step of regulating a flow of current comprises:

applying a potential of three-phase alternating current (AC) to a full-wave rectifier to generate a rectified signal;

converting said rectified signal into a rectangular full-wave form signal; and

rectifying said rectangular full-wave form signal to provide an output signal having voltage and current components.

24. The method of claim 23 wherein the step of converting said rectified signal comprises the steps of:

causing said rectified signal to flow through a single phase inverter bridge; and

controlling the operation of said inverter bridge by applying a pulse width modulated (PWM) rectangular wave form signal to said inverter bridge as a control signal, to cause said inverter bridge to generate said rectangular full-wave form signal.

25. The method of claim 24 wherein the step of controlling the operation of said inverter bridge comprises the steps of:

monitoring said current component of said output signal;

comparing said monitored current to a predetermined reference current to generate a current error signal; and

adjusting said PWM rectangular wave form signal based on said current error signal.

26. The method of claim 24 wherein the step of controlling the operation of said inverter bridge comprises the steps of:

monitoring said voltage component of said output signal;

comparing said monitored voltage to a predetermined reference voltage to generate a voltage error signal;

adjusting said PWM rectangular wave form signal based on said voltage error signal.

27. The method of claim 24 wherein the step of controlling the operation of said inverter bridge comprises the steps of:

monitoring said voltage component of said output signal;

monitoring said current component of said output signal;

comparing said monitored voltage to a predetermined reference voltage to generate a voltage error signal;

comparing said monitored current to a predetermined reference current to generate a current error signal;

selecting either voltage, current, or power regulation;

if voltage regulation has been selected, adjusting said PWM rectangular wave form signal based on said voltage error signal;

if current regulation has been selected, adjusting said PWM rectangular wave form signal based on said current error signal; and

if power regulation has been selected, adjusting said PWM rectangular wave form signal based on said voltage error signal and said current error signal.

28. The method defined in claim 22 wherein the step of controlling the movement of said fusing member further includes the step of providing a status signal corresponding to a status point within said predetermined fusing operation.

29. The method defined in claim 28 wherein the step of regulating the flow of current further includes providing feedback signals corresponding to said flow of current to said fusing member.

30. The method defined in claim 29 wherein the step of synchronizing comprises the steps of:

utilizing said status signal to determine a required level of said flow of current;

comparing said feedback signal to said required level of said flow of current and generating adjustment signals corresponding to the difference between said feedback signals and said required level of said flow of current;

applying said adjustment signals to said step of regulating said flow of current in order to maintain said flow of current at said required level.

31. The method defined in claim 30 wherein the step of regulating the flow of current comprises the steps of:

applying a potential of three-phase alternating current (AC) to a full-wave rectifier to generate a rectified signal;

causing said rectified signal to flow through a single-phase inverter bridge;

controlling operation of said inverter bridge by applying a pulse width modulated (PWM) rectangular wave form signal to said inverter bridge as a control signal, said PWM rectangular wave form signal being selected based upon said adjustment signals, thereby causing said inverter bridge to generate a rectangular full-wave form signal; and

rectifying said rectangular full-wave form signal to provide an output signal having voltage and current components.

32. The method defined in claim 28 wherein said predetermined fusing function corresponds to a predetermined force function.

33. The method defined in claim 32 wherein said step of controlling the movement of said fusing member comprises the steps of:

measuring said force of said fusing member on said plurality of conductors; and

providing a controlling signal corresponding to said measured force in order to move said fusing member in conformance with said predetermined force function.

34. The method defined in claim 28 wherein said predetermined fusing function corresponds to a predetermined displacement function.

35. The method defined in claim 34 wherein the step of controlling the movement of said fusing member comprises the steps of:

measuring displacement of said fusing member from a predetermined location; and

providing a controlling signal corresponding to said measured displacement in order to move said fusing member in conformance with said predetermined displacement function.

38. Apparatus for fusing at least one stator wire and at least one piece of contact hook material together, said apparatus comprising:

a fusing member for applying force and varying heat to soften said contact hook material and to deform said contact hook material around said stator wire;

a grounding member;

means for moving said fusing member relative to said stator wire and said contact hook material in order to cause said fusing member to contact and apply force to said contact hook material thereby deforming said contact hook material intimately around said stator wire;

means for controlling said means for moving said fusing member in accordance with a predetermined physical delivery function to control said applied force;

means for regulating a precise flow of current through said stator wire and said contact hook material from said fusing member to said grounding member to generate said varying heat in said fusing member in accordance with a predetermined electrical delivery function to regulate said precise flow of current and thereby regulate the level of said varying heat so that said contact hook material is softened and therefore, said deforming is precisely controlled, and so that insulation on a portion of said stator wire within said softened deformed contact hook material is vaporized; and

means for synchronizing said means for controlling said means for regulating in order to supply a precise varying level and quantity of heat from said fusing member to said stator wire and said contact hook material at specific, predetermined time intervals, such that said regulating means is essentially instantaneously responsive to the short timings and different heating requirements which occur during fusing of said stator wire to said contact hook material.

39. The method of using a fusing member to fuse together at least one stator wire and at least one piece of contact hook material, the method comprising the steps of:

moving said fusing member relative to said stator wire and said contact hook material in order to cause said fusing member to contact and apply force to said contact hook material thereby forming said contact hook material intimately around said stator wire;

controlling the movement of said fusing member in accordance with a predetermined physical delivery function to control said applied force;

regulating a precise flow of current through said stator wire and said contact hook material from said fusing member to a grounding member to generate varying heat in said fusing member in accordance with a predetermined electrical delivery function to regulate said precise flow of current and thereby regulate the level of said varying heat so that said contact hook material is softened and therefore, said deforming is precisely controlled, and so that insulation on a portion of said stator wire within said softened deformed contact hook material is vaporized; and

synchronizing the control of movement of said fusing member and the regulation of said flow of current in order to supply a precise varying level and quantity of heat from said fusing member to said stator wire and said contact hook material at specific, predetermined time intervals, such that said step of regulating is essentially instantaneously responsive to the short timings and different heating requirements which occur during fusing of said stator wire to said contact hook material.