Testing and display of electrical system impedance

• US 7,215,130 B2
• Filed: 07/15/2003
• Issued: 05/08/2007
• Est. Priority Date: 07/15/2003
• Status: Expired due to Fees

• Current Assignee: Snap-On Incorporated
• Original Assignee: Snap-On Incorporated
• Inventors: Brott, Alejandro P., Willems, Paul A., Goetzelmann, Alan D., Jonker, Gary, Thibedeau, Dennis G.
• Primary Examiner(s): Hirshfeld; Andrew H.
• Assistant Examiner(s): Dole; Timothy J
• Application Number:
  US10/619,187
• Publication Number:
  US 20050012510A1
• Time in Patent Office: 1,393 Days
• Field of Search: 324/715, 324/691
• US Class Current: 324/691
• CPC Class Codes: G01R 31/3842 combining voltage and current measurements
• CPC Class Codes: G01R 31/389 Measuring internal impedance, internal conductance or related variables

Abstract

An automated method is provided for testing an electrical circuit using a system tester. Load leads and sense leads of the tester are connectable to any two points of an electrical circuit, such as in a vehicle system, for displaying in real time the impedance between the tested circuit points. A controller is responsive to various sensed signals to calculate impedance, admittance or conductance, and related parameters, such as available cranking current, and provide results for read out or display. A load may be connected across the circuit points under test, the sensed signals derived from a current sense amplifier, a DC voltage amplifier, a ripple amplifier, and an AC amplifier.

Claims

1. In a testing device including a system tester, load leads connectable at respective first ends to separated points of a vehicle system circuit and connectable at respective second ends to a first set of inputs to the tester, sense leads connectable at respective first ends to the separated points of the vehicle system circuit and connectable at respective second ends to a second set of inputs to the tester, the leads being coupled to the points by Kelvin connections, the improvement comprising:

a pair of conductors attached at a first end to a Kelvin clamp, the pair of conductors attached at a second end to respective terminals of a terminal block, the terminals being insulated from each other, wherein the terminal block is configured for mating to a Kelvin clamp of the testing device.

2. A testing device for a vehicle system circuit, comprising:

a system tester;

load leads connectable at respective first ends to separated points of the vehicle system circuit and connectable at respective second ends to a first set of inputs to the tester;

sense leads connectable at respective first ends to the separated points of the vehicle system circuit and connectable at respective second ends to a second set of inputs to the tester;

a controller configured to perform the steps of;

measuring the impedance, conductance or admittance between the circuit points;

setting the measured impedance, conductance or admittance between the circuit points as a reference value;

prompting a user to move one of the load leads and one of the sense leads from one of the circuit points to a new circuit point;

measuring the impedance, conductance or admittance between the circuit points including the new circuit point; and

generating a test result based on the reference value and the measured impedance, conductance or admittance between the circuit points including the new circuit point.