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
- Patent Classifications (CPCs):
-
G - PHYSICS G01 - MEASURING G01N - INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- 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, Jr, C J. NONDESTRUCTIVE EDDY CURRENT TESTING. United States: N. p., 1961.
Web.
Renken, Jr, C J. NONDESTRUCTIVE EDDY CURRENT TESTING. United States.
Renken, Jr, C J. Tue .
"NONDESTRUCTIVE EDDY CURRENT TESTING". United States.
@article{osti_4018579,
title = {NONDESTRUCTIVE EDDY CURRENT TESTING},
author = {Renken, Jr, C J},
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 = {Tue May 23 00:00:00 EDT 1961},
month = {Tue May 23 00:00:00 EDT 1961}
}