Microprocessor-based hand-held electrical-testing system and method

• US 6,771,073 B2
• Filed: 01/03/2003
• Issued: 08/03/2004
• Est. Priority Date: 01/04/2002
• Status: Active Grant

• Current Assignee: Auto Meter Products Incorporated, Purkey Electrical Consultants
• Original Assignee: Auto Meter Products Incorporated
• Inventors: Henningson, Dale B., Purkey, Bruce A.
• Primary Examiner(s): TIBBITS, PIA FLORENCE
• Application Number:
  US10/336,575
• Publication Number:
  US 20030128036A1
• Time in Patent Office: 578 Days
• Field of Search: 324/426, 324/427, 324/429, 324/430, 320/118, 320/123, 320/134, 320/136, 320/DIG.21, 320/DIG.18, D10/77, D10/78, 340/635, 340/636
• US Class Current: 324/426
• CPC Class Codes: G01R 31/007 using microprocessors or computers
• CPC Class Codes: G01R 31/58 Testing of lines, cables or conductors testing of electric windings G01R31/72

Abstract

The present invention provides methods and systems for testing voltage drops in positive and negative legs of an electrical system and for determining maximal current capacity of the electrical system based on the measured voltage drops. This is accomplished by connecting load leads of a testing unit at a starter or alternator of the electrical system, and connecting voltage leads of the testing unit at a battery of the electrical system. A load of known resistance is applied and a voltage at the load is measured. Voltage drops at the positive and negative legs of the electrical system are determined, based at least in part on the voltage at the load. A maximum current capacity of the electrical system is calculated based on the determined voltage drops.

Claims

1. A method of measuring voltage drops in an electrical system, the method comprising:

connecting a plurality of load leads to a charging component of the electrical system, said plurality of load leads including a positive load lead and a negative load lead, each of said plurality of load leads being coupled to a testing device;

connecting a plurality of voltage leads to a battery of the electrical system, said plurality of voltage leads including a positive voltage lead and a negative voltage lead, said plurality of voltage leads being coupled to said testing device;

applying a load of known resistance to the electrical system by the testing device;

measuring a voltage at the load;

measuring a first voltage drop between the positive load lead and the positive voltage lead; and

measuring a second voltage drop between the negative load lead and the negative voltage lead, wherein measurements of the first and second voltage drops are based, at least in part, on the voltage at the load.

2. The method of claim 1, further comprising calculating a current drawn by the testing device using the measured voltage at the load.

3. The method of claim 2, further comprising calculating a first resistance and a second resistance associated with the plurality of load leads and the plurality of voltage leads, respectively, based on the calculated current and the first and second voltage drops.

4. The method of claim 3, further comprising:

determining a current that would produce a maximum allowable voltage drop in the electrical system, based on the first and second resistances and the first and second voltage drops, respectively.

5. The method of claim 1, wherein the charging component comprises an alternator.

6. The method of claim 1, further comprising determining a condition of the charging component based on the first and second voltage drops.

7. The method of claim 1, further comprising displaying, on the testing device, values associated with the first and second voltage drops.

8. The method of claim 1, wherein the steps are performed in the order listed.

9. A method of measuring voltage drops in positive and negative legs of starting components of an electrical system, the method comprising:

connecting a plurality of load leads to a starting component of the electrical system, the plurality of load leads including a positive load lead and a negative load lead, the plurality of load leads being coupled to a testing device;

connecting a plurality of voltage leads to a battery of the electrical system, the plurality of voltage leads including a positive voltage lead and a negative voltage lead, the plurality of voltage leads coupled to the testing device;

applying a load of known resistance to the electrical system by the testing device;

measuring a voltage at the load;

measuring a first voltage drop between the positive load lead and the positive voltage lead; and

measuring a second voltage drop between the negative load lead and the negative voltage lead, wherein measurements of said first and second voltage drops are based, at least in part, on the voltage at the load.

10. The method of claim 9, further comprising calculating a current drawn by the testing device using the measured voltage at the load.

11. The method of claim 10, further comprising calculating a first resistance and a second resistance associated with the plurality of load leads and the plurality of voltage leads, respectively, based on the calculated current and the first and second voltage drops, respectively.

12. The method of claim 11, further comprising the step of determining a system current that would produce a maximum allowable voltage drop in the electrical system, based on the first and second resistances and the first and second voltage drops.

13. The method of claim 9, wherein the starting component comprises a starter.

14. The method of claim 9, further comprising the step of determining a condition of the starting component based on the first and second voltage drops.

15. The method of claim 14, further comprising the step of indicating the condition of the starting component on the testing device.

16. The method of claim 9, wherein the steps are performed in the order listed.

17. An apparatus for testing and measuring voltage drops in a positive and a negative leg of an electrical system, the apparatus comprising:

a plurality of load leads adapted to provide an electrical connection to a charging component of the electrical system, the plurality of load leads including a positive load lead and a negative load lead;

a plurality of voltage leads adapted to provide an electrical connection to a battery of the electrical system, the plurality of voltage leads including a positive voltage lead and a negative voltage lead;

means for applying a load of known resistance to the electrical system;

means for measuring a voltage at the load; and

means for measuring a first voltage drop between the positive load lead and the positive voltage lead and a second voltage drop between the negative load lead and the negative voltage lead, wherein measurements of said first and second voltage drops are based, at least in part, on the voltage at the load.

18. The apparatus of claim 17, further comprising means for calculating a current drawn by the apparatus using the measured voltage at the load.

19. The apparatus of claim 17, further comprising means for calculating a first resistance and a second resistance associated with the plurality of load leads and the plurality of voltage leads, respectively, based on the calculated current and the first and second voltage drops.

20. The apparatus of claim 19, further comprising means for determining a current that would produce a maximum allowable voltage drop in the electrical system, based on the first and second resistances and the first and second voltage drops.

21. The apparatus of claim 17, wherein the charging component comprises an alternator.

22. The apparatus of claim 17, further comprising means for determining a condition of the charging component based on the first and second voltage drops.

23. The apparatus of claim 17, further comprising a display for displaying values associated with the first and second voltage drops.

24. An apparatus for measuring voltage drops in positive and negative legs of an electrical system, the apparatus comprising:

a plurality of load leads adapted to provide an electrical connection to a starting component of the electrical system, the plurality of load leads including a positive load lead and a negative load lead;

a plurality of voltage leads adapted to provide an electrical connection to a battery of the electrical system, the plurality of voltage leads including a positive voltage lead and a negative voltage lead;

means for applying a load of known resistance to the electrical system;

means for measuring a voltage at the load; and

means for measuring a first voltage drop between the positive load lead and the positive voltage lead and a second voltage drop between the negative load lead and the negative voltage lead, wherein measurements of said first and second voltage drops are based, at least in part, on the voltage at the load.

25. The apparatus of claim 24, further comprising means for calculating a current drawn by the testing device using the measured voltage at the load.

26. The apparatus of claim 25, further comprising means for calculating a first resistance and a second resistance associated with the plurality of load leads and the plurality of voltage leads, respectively, based on the calculated current and the first and second voltage drops.

27. The apparatus of claim 26, further comprising means for determining a system current that would produce a maximum allowable voltage drop in the electrical system, based on the first and second resistances and the first and second voltage drops.

28. The apparatus of claim 24, wherein the starting component comprises a starter.

29. The apparatus of claim 24, further comprising means for determining a condition of the starting component based on the first and second voltage drops.

30. The apparatus of claim 29, further comprising a display for displaying the condition of the starting component.