Test measurement system and method for using same in low voltage systems
AssigneeEngineering Systems Corporation
InventorsMassimo Mitolo, Thomas Joseph Bajzek
Life of this patent
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Abstract
A test measurement system configured to be applied or otherwise coupled to an energized low-voltage receptacle or to live terminals of a feeder/branch circuit to detect the presence of potentially hazardous conditions. The test measurement system can be configured to indicate to a user if a ground-fault, which could occur at a load supplied by that energized low-voltage receptacle or live terminals of a feeder/branch circuit, would cause unsafe touch potentials to an individual.
Claims24
A test measurement system for an electrical system having an energized low-voltage receptacle or live terminals of a feeder/branch circuit;
- the test measurement system comprising:
- a processor configured to determine if a ground-fault at a load supplied by the energized low-voltage receptacle or live terminals of the feeder/branch circuit would cause unsafe touch potentials to an individual, as defined in IEEE and IEC standards.
A method for using a test measurement system for determining if a ground-fault exists that would cause unsafe touch potentials to an individual, as defined in IEEE and IEC standards, in an electrical system having an energized low-voltage receptacle or live terminals of a feeder/branch circuit, comprising:
- determining if the low-voltage receptacle or the live terminals are properly energized;
- measuring a current in the test circuit in which a first load resistance is selectively connected if the low-voltage receptacle or the live terminals are properly energized and then storing the measured current value for comparison to a predetermined minimum value of acceptable current;
- replacing the first load resistance in the test circuit with a second load resistance and measuring a voltage across the second load resistance for comparison to a predetermined minimum value of acceptable voltage;
- replacing the second load resistance in the test circuit with a third load resistance if the measured voltage across the second load resistance is greater than the predetermined voltage test criteria and measuring and storing a voltage and a current across the third load resistance;
- running a fault-loop routine;
- determining a resistance of the protective conductor of the electrical system;
- determining and storing a value for a prospective touch voltage of the operably coupled energized low-voltage receptacle or live terminals;
- and
- determining if the measured voltage exceeds a predetermined voltage value.
Dependencies are inferred from the claim text.