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coil impedance

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Series: ASM Handbook
Volume: 17
Publisher: ASM International
Published: 01 August 2018
DOI: 10.31399/asm.hb.v17.a0006450
EISBN: 978-1-62708-190-0
.... This article discusses the advantages and limitations of eddy-current inspection, as well as the development of the eddy-current inspection process. It reviews the principal operating variables encountered in eddy-current inspection: coil impedance, electrical conductivity, magnetic permeability, lift-off...
Series: ASM Desk Editions
Publisher: ASM International
Published: 01 December 1998
DOI: 10.31399/asm.hb.mhde2.a0003234
EISBN: 978-1-62708-199-3
... and nonferromagnetic metals and metal parts. Giving a brief introduction on the uses of eddy-current inspection, this article discusses the operating principles and the principal operating variables encountered in eddy-current inspection, including coil impedance, electrical conductivity, magnetic permeability, lift...
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Published: 01 August 2018
Fig. 4 Typical impedance-plane diagram derived by placing an inspection coil sequentially on a series of thick pieces of metal, each with a different IACS electrical resistance or conductivity rating. The inspection frequency was 100 kHz. More
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Published: 01 August 2018
Fig. 13 Impedance diagram for a long coil encricling a thin-wall nonferromagnetic tube, showing also an equivalent circuit. R is series resistance; R s is effective shunt resistance, ω is 2π f ; f is frequency; G is shunt conductance; L 0 is coil inductance; Z is impedance; j More
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Published: 01 August 2018
Fig. 14 Impedance diagram for a long coil encircling a thin-wall nonferromagnetic tube showing impedance as a function of frequency More
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Published: 01 August 2018
Fig. 15 Effects of variations in tube radius on the impedance of a long coil of fixed diameter encircling a thin-wall nonferromagnetic tube. G is conductance; r is tube radius; r c is coil radius. More
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Published: 01 August 2018
Fig. 16 Normalized impedance diagram for a long coil encircling a solid cylindrical nonferromagnetic bar showing also the locus for a thin-wall tube (which is similar to the loci in Fig. 14 and 15 ). k , electromagnetic wave propagation constant for a conducting material, or ω μ σ More
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Published: 01 August 2018
Fig. 17 Effect of variation in bar diameter on the impedance of a long coil encircling a solid cylindrical nonferromagnetic bar More
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Published: 01 December 1998
Fig. 4 Typical impedance-plane diagram derived by placing an inspection coil sequentially on a series of thick pieces of metal, each with a different International Annealed Copper Standard (IACS) electrical resistance or conductivity rating. The inspection frequency is 100 kHz. More
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Published: 01 August 2018
Fig. 17 (a) Example of half-bridge direct-drive voltage across a T-coil load (approximately 60 V pp ). (b) Resulting current through the coil (approximately 30 A pp ). The transmitter output circuit has a meander coil impedance of approximately 0.1 Ω resistance and 800 nH inductance More
Series: ASM Handbook
Volume: 17
Publisher: ASM International
Published: 01 August 2018
DOI: 10.31399/asm.hb.v17.a0006458
EISBN: 978-1-62708-190-0
... to the elastic-wave frequency and amplitude (or some component thereof) being reflected from or traveling parallel to the metal surface adjacent to the R-coil. Both this coil and the source of its voltage (which is the elastic-wave amplitude near the material surface) frequently have a low impedance. Most EMAT...
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Published: 01 August 2018
Fig. 27 Four types of eddy current instruments. (a) A simple arrangement, in which voltage across the coil is monitored. (b) Typical impedance bridge. (c) Impedance bridge with dual coils. (d) impedance bridge with dual coils and a reference sample in the second coil More
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Published: 01 December 1998
Fig. 11 Four types of eddy-current instruments. (a) A simple arrangement, in which voltage across the coil is monitored. (b) Typical impedance bridge. (c) Impedance bridge with dual coils. (d) Impedance bridge with dual coils and a reference sample in the second coil More
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Published: 01 August 2018
between the T- and R-EMATs is via the acoustic wave propagating in the metal. It is this coupling that is described by the (intrinsic) transfer impedance. In the pulse-echo version, acoustic coupling is via elastic energy reflected from the back (far) surface. As illustrated, the R-coil is a voltage More
Series: ASM Handbook
Volume: 4B
Publisher: ASM International
Published: 30 September 2014
DOI: 10.31399/asm.hb.v04b.a0005924
EISBN: 978-1-62708-166-5
... load and output impedance depends on the system design and application. However, the ability of different types of power supplies to broadband tune and to make full power into different loads and coil impedance varies widely. Some power supplies need to have 100% over rating of power to essentially...
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Published: 30 September 2014
Fig. 14 Schematic circuit diagrams of low- to medium-frequency heat stations illustrating capacitor and transformer adjustments when using (a) an autotransformer for high-impedance induction coils and (b) an isolation transformer for low-impedance induction coils. Similar circuits are used More
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Published: 01 August 2018
, to the sensitive receiver input. (iii) T 1 and T 2 are impedance-matching transformers to maximize power transfer from the driver to the T-coil. (Frequently, only one transformer is needed, but a larger EMAT system bandwidth, if needed, often can be achieved using multiple impedance-matching transformers.) (iv More
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Published: 01 August 2018
Fig. 19 Phase-discrimination technique for reducing the effect of a particular variable on one output-signal channel during eddy-current inspection. (a) Impedance diagram for a probe or pancake coil in the vicinity of a nonferromagnetic part. (b) Enlarged view of the area in the vicinity More
Series: ASM Handbook
Volume: 4C
Publisher: ASM International
Published: 09 June 2014
DOI: 10.31399/asm.hb.v04c.a0005846
EISBN: 978-1-62708-167-2
... . The return path for magnetic flux is on the inside of the coil. Power density in the workpiece is proportional to the magnetic flux density squared, and flux density is magnetic flux divided by the cross-sectional area through which it is flowing. The magnetic impedance of an area is directly proportional...
Series: ASM Handbook
Volume: 6
Publisher: ASM International
Published: 01 January 1993
DOI: 10.31399/asm.hb.v06.a0001368
EISBN: 978-1-62708-173-3
... requirements permit. Water-cooled copper conductors are used to carry the power to the coil or contacts. These conductors must be of minimum length and closely spaced to minimize impedance losses. The use of induction coils or electrical contacts to deliver HF power to the workpiece has specific advantages...