Source related potential indicating continuity tester

• US 4,031,461 A
• Filed: 01/23/1976
• Issued: 06/21/1977
• Est. Priority Date: 01/23/1976
• Status: Expired due to Term

• Current Assignee: Deere & Company
• Original Assignee: Deere & Company
• Inventors: Reiner, Carl Casper
• Primary Examiner(s): Strecker, Gerard R.
• Application Number:
  US05/651,808
• Time in Patent Office: 515 Days
• Field of Search: 324/29.5, 324/51, 324/72.5, 324/133, 340/248 A, 340/248 B, 340/248 C, 340/256, 340/255
• US Class Current: 324/556
• CPC Class Codes: G01R 31/50 Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections testing of sparking plugs H01T13/58
• CPC Class Codes: G01R 31/52 Testing for short-circuits, leakage current or ground faults
• CPC Class Codes: G01R 31/54 Testing for continuity
• CPC Class Codes: G01R 31/67 Testing the correctness of wire connections in electric apparatus or circuits

Abstract

An electrical system fault detector for connection across the source terminals of an electrical system includes circuitry responsive to the relative potentials and current flows between the terminals and a selected point in the electrical system to provide a digital indication of acceptable continuity when current can flow between the selected point and one of the terminals and the potentials thereat are approximately equal. A lack of an indication of acceptable continuity indicates a fault such as an open circuit oran excessive impedance between the selected point and the terminal to which it is connected. An incongruous indication would further indicate a fault such as an incorrect connection or a short circuit. Further circuitry produces and is responsive to an oscillating signal subject to line impedances to distinguish between an open circuit and an excessive impedance.

Claims

1. A detector for determining continuity in an electrical circuit between a selected point in the circuit and an electrical source in the circuit, said source having first and second source potentials, comprising:

probe means adapted to be placed in contact with the selected point;

first and second connector means adapted to be connected respectively to the first and second source potentials;

first indicator means connected to the probe and first connector means responsive to the potentials thereat to provide a first digital, off-on indication when the potentials are approximately equal thereby indicating continuity in the circuit between the point and first source potential; and

second indicator means connected to the probe and second connector means responsive to the potentials thereat to provide a second digital, off-on indication when the potentials are approximately equal thereby indicating continuity in the circuit between the point and second source potential.

2. The detector as claimed in claim 1 wherein the first and second indicator means includes first and second protective means for protecting the first and second indicator means from damage when the first connector means is connected to the second source potential and the second connector means is connected to the first source potential.

3. The detector as claimed in claim 1 including means for maintaining the first digital indication when the probe and first connector means potentials are intermittently approximately equal and maintaining the second digital indication when the probe and second connector means potentials are intermittently approximately equal.

4. The detector as claimed in claim 1 including means for applying an oscillating signal to the probe means;

and means responsive to a predetermined attenuation of the signal for providing an indication thereof.

5. A detector for determining continuity in an electrical circuit between a selected point in the circuit and a source in the circuit, said source having first, second, and third source potentials, comprising:

probe means adapted to be placed in contact with the selected point;

first, second, and third connector means adapted to be connected to the first, second and third source potentials;

first indicator means connected to the probe and first connector means responsive to the potentials thereat to provide a first indication when the potentials are approximately equal thereby indicating continuity in the circuit between the point and the first source potential;

second indicator means connected to the probe and second connector means responsive to the potentials thereat to provide a second indication when the potentials are approximately equal thereby indicating continuity in the circuit between the point and the second source potential;

third indicator means connected to the probe and third connector means responsive to the potentials thereat to provide a third indication when the potentials are approximately equal thereby indicating continuity in the circuit between the point and third source potential.

6. The detector as claimed in claim 5 wherein the first, second, and third indicator means includes first, second, and third protective means for protecting the first, second, and third indicator means from damage when the first connector means is connected to the second or third source potential, the second connector means is connected to the first or third source potential, or the third connector means is connected to the first or second source potential.

7. The detector as claimed in claim 5 including means for maintaining the first indication when the probe means and first connector means potentials are intermittently approximately equal, the second indication when the probe means and second connector means potentials are intermittently approximately equal, and the third indication when the probe means and third connector means potentials are intermittently approximately equal.

8. The detector as claimed in claim 5 including means for floating the quiescent potential of the probe means at a potential between the potential at the first and second connector means potentials.

9. The detector as claimed in claim 5 including means for floating the quiescent potential of the probe means at a potential between the potential of the second and third connector means.

10. The detector as claimed in claim 5 including means for applying an oscillating signal to the probe means;

and means responsive to a predetermined attenuation of the signal for providing an indication thereof.

11. The detector as claimed in claim 5 wherein the second indicator means includes means for preventing operation of the second indicator means when the second connector means is connected to the first or second source potential.

12. A detector for determining continuity in an electrical circuit between a selected point in the circuit and a source in the circuit, said source having first and second source potentials, comprising:

probe means adapted to be placed in contact with the selected point;

first and second connector means adapted to be connected respectively to the first and second source potentials;

first indicator means connected to the probe and first connector means responsive to the potentials thereat to provide a first digital, off-on indication when the potentials are within a first predetermined fixed range of each other thereby indicating acceptable continuity in the circuit between the point and the first source potential; and

second indicator means connected to the probe and second connector means responsive to the potentials thereat to provide a second digital, off-on indication when the potentials are within a second predetermined fixed range of each other thereby indicating acceptable continuity between the point and the second source potential.

13. The detector as claimed in claim 12 wherein the first and second indicator means include first and second protective means for protecting the first and second indicator means from damage when the first connector means is connected to the second source potential and the second connector means is connected to the first source potential or when the source potentials undergo polarity reversals.

14. The detector as claimed in claim 12 including means for maintaining the first or second digital indications when the potential at the probe means is intermittently within the first or second predetermined fixed range.

15. The detector as claimed in claim 12 including means for applying an oscillating signal to the probe means;

and means responsive to a predetermined attenuation of the signal for providing an indication thereof.

16. A detector for determining continuity in an electrical circuit between a selected point in the circuit and a source in the circuit, said source having first, second, and third source potentials, comprising:

probe means adapted to be placed in contact with the selected point;

first, second, and third connector means adapted to be connected respectively to the first, second, and third source potentials;

first indicator means connected to probe and first connector means responsive to the potentials thereat to provide a first indication when the potentials are within a first predetermined fixed range of each other thereby indicating acceptable continuity in the circuit between the point and the first source potential;

second indicator means connected to the probe and second connector means responsive to the potentials thereat to provide a second indication when the potentials are within a second predetermined fixed range of each other thereby indicating acceptable continuity in the circuit between the point and the second source potential;

third indicator means connected to the probe and third connector means responsive to the potentials thereat to provide a third indication when the potentials are within a third predetermined fixed range of each other thereby indicating acceptable continuity in the circuit between the point and third source potential.

17. The detector as claimed in claim 16 wherein the first, second, and third indicator means includes first, second, and third protective means for protecting the first, second, and third indicator means from damage when the first connector means is connected to the second or third source potential, or the second connector means is connected to the first or third source potential, or the third connector means is connected to the first or second source potential or when the source potentials undergo polarity reversals.

18. The detector as claimed in claim 16 wherein the first, second, and third indicator means includes first, second, and third extender means for maintaining the first, second, or third indications when the probe means potential is intermittently within the first, second, or third predetermined fixed range.

19. The detector as claimed in claim 16 including means for floating the quiescent potential of the probe means at a potential between the first and second predetermined fixed ranges.

20. The detector as claimed in claim 16 including means for floating the quiescent potential of the probe means at a potential between the second and third predetermined fixed ranges.

21. The detector as claimed in claim 16 including means connected to the first and third connector means and the probe means for applying an oscillating signal to the probe means;

and means connected to the probe means responsive to a predetermined attenuation of the signal for providing an indication thereof thereby indicating continuity between the point and one of the source potentials.

22. A detector for determining continuity in an electrical circuit between a selected point in the circuit and a source in the circuit, said source having first and second source potentials, comprising:

probe means adapted to be placed in contact with the selected point;

first and second connector means adapted to be connected respectively to the first and second source potentials;

first indicator means connected to the probe and first connector means responsive to the potentials thereat to provide a first digital, off-on indication when the potential at the probe means is a first predetermined percentage of the potential at the first connector means thereby indicating acceptable continuity in the circuit between the point and the first source potential;

second indicator means connected to the probe and second connector means responsive to the potentials thereat to provide a second digital, off-on indication when the potential at the probe means is a second predetermined percentage of the potential at the second connector means thereby indicating acceptable continuity between the point and the second source potential.

23. The detector as claimed in claim 22 wherein the first and second indicator means includes first and second protective means for protecting the first and second indicator means from damage when the first connector means is connected to the second source potential and the second connector means is connected to the first source potential or when the source potentials undergo polarity reversals.

24. The detector as claimed in claim 22 wherein the first and second indicator means includes first and second extender means for maintaining the first and second digital indications when the potential at the probe means is intermittently within the first or second predetermined percentage.

25. The detector as claimed in claim 22 including means for applying an oscillating current signal to the probe means;

and means responsive to a predetermined attenuation of the signal for providing an indication thereof thereby indicating continuity between the point and one of the source potentials.

26. A detector for determining continuity in an electrical circuit between a selected point in the circuit and a source in the circuit, said source having first, second, and third source potentials, comprising:

probe means adapted to be placed in contact with the selected point;

first, second, and third connector means adapted to be connected respectively to the first, second, and third source potentials;

first indicator means connected to the probe and first connector means responsive to the potentials thereat to provide a first indication when the potential at the probe means is a first predetermined percentage of the potential at the first connector means thereby indicating acceptable continuity in the circuit between the point and the first source potential;

second indicator means connected to the probe and second connector means responsive to the potentials thereat to provide a second indication when the potential at the probe means is a second predetermined percentage of the potential at the second connector means thereby indicating acceptable continuity in the circuit between the point and the second source potential;

third indicator means connected to the probe and third connector means responsive to the potentials thereat to provide a third indication when the potential at the probe means is a third predetermined percentage of the potential at the third connector means thereby indicating acceptable continuity in the circuit between the point and third source potential.

27. The detector as claimed in claim 26 wherein the first, second, and third indicator means includes first, second, and third protective means for protecting the first, second, and third indicator means from damage when the first connector means is connected to the second or third source potential, or the second connector means is connected to the first or third source potential, or the third connector means is connected to the first or second source potential, or when the source potentials undergo polarity reversals.

28. The detector as claimed in claim 26 wherein the first, second, and third indicator means includes first, second, and third extender means for maintaining the first, second, or third indication when the probe means potential is intermittently within the first, second, or third predetermined percentage of the potential at the first, second, or third connector means, respectively.

29. The detector as claimed in claim 26 including means for floating the quiescent potential of the probe means at a potential between the first and second predetermined percentages.

30. The detector as claimed in claim 26 including means for floating the quiescent potential of the probe means at a potential between the second and third predetermined percentages.

31. The detector as claimed in claim 26 including means connected to the first and third connector means and the probe means for applying an oscillating current signal to the probe means;

and means connected to the probe means responsive to a predetermined attenuation of the signal for providing an indication thereof thereby indicating continuity between the point and one of the source potentials.

32. A detector for determining continuity in an electrical circuit between a selected point in the circuit and electrical source in the circuit, said source having first and second source potentials, comprising:

probe means adapted to be placed in contact with the selected point;

first and second connector means adapted to be connected respectively to the first and second source potentials;

first and second indication means connected respectively to the first and second connector means;

first switching means connected to the probe means and the first indication means and operatively associated with the first connector means responsive to a potential at the probe means within a first predetermined fixed range of the potential at the first connector means to cause the first indication means to provide a first indication; and

second switching means connected to the probe means and the second indication means and operatively associated with the second connector means responsive to a potential at the probe means within a second predetermined fixed range of the potential at the second connector means to cause the second indication means to provide a second indication.

33. The detector as claimed in claim 32 wherein the first and second switching means include first and second protective means for protecting the first and second switching means from damage when the first connector means is connected to the second source potential and the second connector means is connected to the first source potential or when the source potentials undergo polarity reversals.

34. The detector as claimed in claim 32 including means for maintaining the first or second indications when the potential at the probe means is intermittently within the first or second predetermined fixed range.

35. The detector as claimed in claim 32 including means for applying an oscillating current signal to the probe means;

and means responsive to a predetermined attenuation of the oscillating signal for providing an indication thereof.

36. The detector as claimed in claim 32 including continuity indication means connected to the first connector means;

oscillator means connected to the first and third connector means to convert a current flow therebetween to an oscillating current signal and connected to the probe means to impose the oscillating current signal thereon;

rectification means connected to the probe means responsive to the oscillating current signal to provide an output proportional thereto; and

comparator means connected to the rectification means and the continuity indication means responsive to a predetermined output from the rectification means to cause the continuity indication means to provide a continuity indication.

37. A detector for determining continuity in an electrical circuit between a selected point in the circuit and an electrical source in the circuit, said source having first, second and third source potentials, comprising:

probe means adapted to be placed in contact with the selected point;

first, second, and third connector means adapted to be connected respectively to the first, second, and third source potentials;

first indication means connected to the first connector means;

second indication means connected to the first and third connector means;

third indication means connected to the first indication means and the third connector means;

first switching means connected to the probe means, the first indication means, and the first connector means responsive to a potential at the probe means within a first predetermined fixed range of the potential at the first connector means to cause the first indicator means to provide a first indication;

second switching means connected to the probe means, the second connector means, and the second indication means responsive to a potential at the probe means within a second and third predetermined fixed ranges of the potential at the second connector means to cause the second indication means to provide a second indication; and

third switching means connected to the probe means, the third connector means, and the third indication means responsive to a potential at the probe means within a fourth predetermined fixed range with the potential at the third connector means to cause the third indication means to provide a third indication.

38. The detector as claimed in claim 37 wherein the first and third indication means includes first and second protective means for protecting respectively the first and third switching means from damage when the first connector means is connected to the second or third source potential, or the second connector means is connected to the first or third source potential, or the third connector means is connected to the first or second source potential or when the source potentials undergo polarity reversals.

39. The detector as claimed in claim 37 including extender means connected to the first switching means and the first indication means for maintaining the first indication when the probe means potential is intermittently within the first predetermined fixed range;

second extender means connected to the second switching means and the second indication means for maintaining the second indication when the probe means potential is intermittently within the second or third predetermined fixed range; and

third extender means connected to the third switching means and the third indication means for maintaining the third indication when the probe means potential is intermittently within the fourth predetermined fixed range.

40. The detector as claimed in claim 37 including means for floating the quiescent potential of the probe means at a potential between the first and second predetermined fixed ranges.

41. The detector as claimed in claim 37 including means for floating the quiescent potential of the probe means at a potential between the third and fourth predetermined fixed ranges.

42. The detector as claimed in claim 37 including continuity indication means connected to the first connector means;

oscillator means connected to the first and third connector means to convert a current flow therebetween to an oscillating current signal and connected to the probe means to impose the oscillating current signal thereon;

rectification means connected to the probe means responsive to the oscillating current signal to provide an output proportional thereto; and

comparator means connected to the rectification means and to the continuity means responsive to a predetermined output from the rectification means to cause the continuity indication means to provide a continuity indication.

43. A detector for determining continuity in an electrical circuit between a selected point in the circuit and a source in the circuit, said source having first, second, and third source potentials comprising:

probe means adapted to be placed in contact with the selected point;

first, second, and third connector means adapted to be connected respectively to the first, second, and third source potentials;

first and third indication means connected respectively to the first and third connector means;

second indicator means operatively associated with the second connector means;

first switching means connected to the probe means, the first and second connector means, and the first indication means responsive to the potentials at the first and second connector means and the probe means to cause the first indication means to provide an indication when the potential at the probe means is a first predetermined percentage of the potential between the first and second connector means;

second switching means connected to the probe means, the first and second and third connector means, and the second indication means responsive to the potential at the probe means and the first, second, and third connector means to provide a second indication when the potential at the probe means is a second predetermined percentage of the potential at the second connector means;

third switching means connected to the probe means, the second and third connector means, and the third indication means responsive to the potentials at the second and third connector means and the probe means to cause the third indication means to provide a third indication when the potential at the probe means is a third predetermined percentage of the potential at the third connector means.

44. The detector as claimed in claim 43 wherein the first, second, and third indicator means includes first, second, and third protective means for protecting respectively the first, second, and third indicator means from damage when the first connector means is connected to the second or third source potential, or the second connector means is connected to the first or third source potential, or the third connector means is connected to the first or second source potential or when the source potentials undergo polarity reversals.

45. The detector as claimed in claim 43 wherein the first, second, and third indicator means includes first, second, and third extender means for maintaining the first, second, or third indication when the probe means potential is intermittently within the first, second, or third predetermined percentage of the potentials at the first, second, or third connector means, respectively.

46. The detector as claimed in claim 43 including means for floating the quiescent potential of the probe means at a potential between the first and second predetermined percentages.

47. The detector as claimed in claim 43 including means for floating the quiescent potential of the probe means at a potential between the second and third predetermined percentages.

48. The detector as claimed in claim 43 including continuity indicator means connected to the first connector means;

oscillator means connected to the first and third connector means to convert a current flow therebetween into an oscillating current signal and connected to the probe means to impose the oscillating current signal thereon;

rectification means connected to the probe means responsive to the oscillating current signal to provide an output proportional thereto; and

comparator means connected to the rectification means and the continuity indication means responsive to a predetermined output from the rectification means to cause the continuity indication means to provide an indication.