US3582774A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Circuit impedance measuring device employing clamp on magnetic current sensor
Assignee: Ford Motor Co
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Filing: 1969-03-13
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Granted: 1971-06-01
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Expires: 1989-03-13
Abstract
Abstract This disclosure relates to an electrical component impedance measuring device that is capable of measuring the impedance of an electrical component permanently connected in an electrical circuit. It comprises a source of electrical energy with means coupled to this source for connecting the electrical component in circuit with the source. A split-magnetic core having an opening position therein is supported by means that position a lead from the electrical component through this opening with the lead carrying current that flows only through the electrical component whose impedance is to be measured. Means are coupled to the core for sensing and measuring the flux in this core.
Inventors
- 👤 Robert L Forgacs
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 13:55
CPC Classifications
G; G01; G01R; G01R27/00; G01R27/02
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
207 words
An in-circuit impedance measuring device for measuring the impedance of an electrical component permanently connected in an electrical circuit comprising an alternating source of electrical energy, a first circuit including a variable impedance connected in series with said source of electrical energy, a second circuit including an unknown in-circuit impedance connected in series with said alternating source of electrical energy, said first circuit connected in parallel with said second circuit, a split ferromagnetic core having a central opening therein, a lead from said first circuit passing through said opening, and means supporting said split core for positioning a lead from said second circuit and said unknown in-circuit impedance through said central opening in a direction to induce flux in said core due to current flow through said lead in an opposite direction from the flux induced in said core by current flow through the lead from said first circuit, and a detector coupled to said core for sensing the net flux therein, and means for changing the value of the variable impedance to a value where the net flux in said ferromagnetic core is zero, and readout means coupled to said last mentioned means for determining the value of said variable impedance and hence said unknown impedance.
Claim 2
Dependent Claim
207 words
An in-circuit impedance measuring device for measuring the impedance of an electrical component permanently connected in an electrical circuit comprising an alternating source of electrical energy, a first circuit including a variable impedance connected in series with said source of electrical energy, a second circuit including an unknown in-circuit impedance connected in series with said alternating source of electrical energy, said first circuit connected in parallel with said second circuit, a split ferromagnetic core having a central opening therein, a lead from said first circuit passing through said opening, and means supporting said split core for positioning a lead from said second circuit and said unknown in-circuit impedance through said central opening in a direction to induce flux in said core due to current flow through said lead in an opposite direction from the flux induced in said core by current flow through the lead from said first circuit, and a detector coupled to said core for sensing the net flux therein, and means for changing the value of the variable impedance to a value where the net flux in said ferromagnetic core is zero, and readout means coupled to said last mentioned means for determining the value of said variable impedance and hence said unknown impedance.
Claim 3
Dependent Claim
14 words
The combination of claim 1 in which said variable impedance is a variable resistor.
Claim 4
Dependent Claim
17 words
The combination of claim 2 in which said unknown in-circuit impedance is a resistor of unknown value.
Claim 5
Dependent Claim
88 words
The combination of claim 2 in which said unknown in-circuit impedance is a capacitor of unknown value and in which a phase shifting means is connected in circuit with said variable resistor for shifting the phase of the current through said lead from said first circuit through substantially 90* and maintaining the amplitude of the current through said variable resistor and lead from said first circuit substantially equal, and said leads are passed through said opening such that the phase angle between the currents therein is substantially 180*.
Claim 6
Dependent Claim
89 words
The combination of claim 2 in which said unknown in-circuit impedance is an inductor of unknown value and in which a phase shifting means is connected in circuit with said variable resistor for shifting the phase of the current through said lead from said first circuit through substantially 90* and maintaining the amplitude of the current through said variable resistor and said lead from said first circuit substantially equal, and said leads are passed through said opening such that the phase angle between the currents therein is substantially 180*.
Claim 7
Dependent Claim
177 words
An in-circuit impedance measuring device for measuring the impedance of an electrical component permanently connected in an electrical circuit comprising a source of electrical energy, a first circuit including a resistor connected in series with said source of electrical energy, a second circuit including an unknown in-circuit resistor connected in series with said source of electrical energy, said first circuit connected in parallel with said second circuit, a split ferromagnetic core having a central opening therein, a lead from said first circuit passing through said opening, and means supporting said split core for positioning a lead from said second circuit and said unknown in-circuit resistor through said central opening in a direction to induce flux in said core due to current flow through said lead in an opposite direction from the flux induced in said core by current flow through the lead from said first circuit, and a Hall generator coupled to said core for sensing the net flux therein, and readout means coupled to said Hall generator for determining the value of said unknown in-circuit resistor.
Claim 8
Dependent Claim
177 words
An in-circuit impedance measuring device for measuring the impedance of an electrical component permanently connected in an electrical circuit comprising a source of electrical energy, a first circuit including a resistor connected in series with said source of electrical energy, a second circuit including an unknown in-circuit resistor connected in series with said source of electrical energy, said first circuit connected in parallel with said second circuit, a split ferromagnetic core having a central opening therein, a lead from said first circuit passing through said opening, and means supporting said split core for positioning a lead from said second circuit and said unknown in-circuit resistor through said central opening in a direction to induce flux in said core due to current flow through said lead in an opposite direction from the flux induced in said core by current flow through the lead from said first circuit, and a Hall generator coupled to said core for sensing the net flux therein, and readout means coupled to said Hall generator for determining the value of said unknown in-circuit resistor.
Claim 9
Dependent Claim
153 words
An in-circuit impedance measuring device for measuring the impedance of an electrical component, which comprises: an alternating source of electrical energy; a split ferromagnetic core having a central opening therein, said split core being adaptable for positioning around said electrical component or a lead thereof, an electrical current in said electrical component producing a magnetic flux in said ferromagnetic core; detector means coupled to said core for indicating the existence of a net flux therein; an adjustable impedance connected between the terminals of said source, said adjustable impedance being electrically connected to a lead wire passing through said central opening in said split ferromagnetic core, a current from said source of electrical energy through said lead wire producing a magnetic flux in opposition to the flux produced by said current in said electrical component; and means for connecting said electrical component to be measured in electrical circuit with said source of electrical energy.
Claim 10
Dependent Claim
153 words
An in-circuit impedance measuring device for measuring the impedance of an electrical component, which comprises: an alternating source of electrical energy; a split ferromagnetic core having a central opening therein, said split core being adaptable for positioning around said electrical component or a lead thereof, an electrical current in said electrical component producing a magnetic flux in said ferromagnetic core; detector means coupled to said core for indicating the existence of a net flux therein; an adjustable impedance connected between the terminals of said source, said adjustable impedance being electrically connected to a lead wire passing through said central opening in said split ferromagnetic core, a current from said source of electrical energy through said lead wire producing a magnetic flux in opposition to the flux produced by said current in said electrical component; and means for connecting said electrical component to be measured in electrical circuit with said source of electrical energy.
Claim 11
Dependent Claim
112 words
An in-circuit impedance measuring device in accordance with claim 7, in which said adjustable impedance is an adjustable resistor, in which said electrical component to be measured is a capacitor of unknown value, and in which a phase shifting means is connected in circuit with said variable resistor for shifting the phase of the current through said lead wire through substantially 90* with respect to the current in said adjustable resistor, thereby, to enable said electrical component or a lead thereof to be positioned so that the magnetic flux produced by a current therein is substantially 180* out of phase with the magnetic flux produced by the current in said lead wire.
Claim 12
Dependent Claim
122 words
An in-circuit impedance measuring device in accordance with claim 7, in which said adjustable impedance is an adjustable resistor, in which said electrical component to be measured is an inductor of unknown value, and in which a phase shifting means is connected in circuit with said adjustable resistor for shifting the phase of the current through said lead wire through substantially 90* with respect to the current in said adjustable resistor, thereby, to enable said electrical component to be positioned in said split ferromagnetic core so that the magnetic flux in said core produced by the current in said electrical component is substantially 180* out of phase with the magnetic flux in said core produced by the current in said lead wire.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-05-31 | 1974-11-30 | 1975-06-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-31 | 1978-11-30 | 1979-06-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-31 | 1982-11-30 | 1983-06-01 | $7700.00 | Window Closed / Lapsed |