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Title: NONDESTRUCTIVE EDDY CURRENT TESTING

Abstract

An eddy current testing device is described for measuring metal continuity independent of probe-to-sample spacing. An inductance would test probe is made a leg of a variable impedance bridge and the bridge is balanced with the probe away from the sample. An a-c signal is applied across the input terminals of the bridge circuit. As the probe is brought into proximity with the metal sample, the resulting impedance change in the probe gives an output signal from the bridge whose phase angle is proportional to the sample continuity and amplitude is proportional to the probe-tosample spacing. The output signal from the bridge is applied to a compensating network where, responsive to amplitude changes from the bridge output signal, a constant phased voltage output is maintained when the sample is continuous regardless of probe-to-sample spacing. A phase meter calibrated to read changes in resistivity of the metal sample measures the phase shift between the output of the compensating network and the original a-c signal applied to the bridge.

Inventors:
Issue Date:
Research Org.:
Originating Research Org. not identified
OSTI Identifier:
4018579
Patent Number(s):
2985824
Assignee:
U.S. Atomic Energy Commission DTIE; NSA-15-017123
NSA Number:
NSA-15-017123
Resource Type:
Patent
Resource Relation:
Other Information: Orig. Receipt Date: 31-DEC-61
Country of Publication:
United States
Language:
English
Subject:
ENGINEERING AND EQUIPMENT; BRIDGE CIRCUITS; CIRCUITS; CURRENTS; EDDY CURRENTS; ELECTRIC CONDUCTIVITY; ELECTRIC METERS; ELECTRIC POTENTIAL; ELECTRIC PROBES; IMPEDANCE; MATERIALS TESTING; MEASURED VALUES; METALS; SIGNALS; STANDARDS; VARIATIONS

Citation Formats

Renken, C.J. Jr. NONDESTRUCTIVE EDDY CURRENT TESTING. United States: N. p., 1961. Web.
Renken, C.J. Jr. NONDESTRUCTIVE EDDY CURRENT TESTING. United States.
Renken, C.J. Jr. Tue . "NONDESTRUCTIVE EDDY CURRENT TESTING". United States.
@article{osti_4018579,
title = {NONDESTRUCTIVE EDDY CURRENT TESTING},
author = {Renken, C.J. Jr.},
abstractNote = {An eddy current testing device is described for measuring metal continuity independent of probe-to-sample spacing. An inductance would test probe is made a leg of a variable impedance bridge and the bridge is balanced with the probe away from the sample. An a-c signal is applied across the input terminals of the bridge circuit. As the probe is brought into proximity with the metal sample, the resulting impedance change in the probe gives an output signal from the bridge whose phase angle is proportional to the sample continuity and amplitude is proportional to the probe-tosample spacing. The output signal from the bridge is applied to a compensating network where, responsive to amplitude changes from the bridge output signal, a constant phased voltage output is maintained when the sample is continuous regardless of probe-to-sample spacing. A phase meter calibrated to read changes in resistivity of the metal sample measures the phase shift between the output of the compensating network and the original a-c signal applied to the bridge.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1961},
month = {5}
}