The universal impedance diagram of the ferrite pot core eddy current transducer

1989 ◽  
Vol 25 (3) ◽  
pp. 2639-2645 ◽  
Author(s):  
S.N. Vernon
Keyword(s):  
Eddy Current ◽  
Impedance Diagram ◽  
Current Transducer ◽  
Eddy Current Transducer

Noninvasive Electromagnetic Evaluation of Bjo¨rk-Shiley Heart Valves: Lifetime Prediction

2008 ◽  
Author(s):  
Raimond Grimberg ◽  
Adriana Savin ◽  
Shiu C. Chan ◽  
Rozina Steigmann ◽  
Lalita Udpa ◽  
...  
Keyword(s):  
Eddy Current ◽  
Heart Valves ◽  
Probability Of Detection ◽  
New Method ◽  
Lifetime Prediction ◽  
Prosthetic Heart Valves ◽  
In Vitro Experiments ◽  
Current Transducer ◽  
Eddy Current Transducer

Prosthetic heart valves of the Bjork-Shiley Convexo-Concave (BSCC) type have long been used extensively in implants; however, there have been reports of cases where one component of the valves failed, leading to the demise of the patient. This paper presents a new method for noninvasive electromagnetic evaluation for this type of valve, using an eddy current transducer with orthogonal coils. In vitro experiments have shown that discontinuities of outlet strut with depths equal or larger than 0.4mm can be detected with a probability of detection (POD) of 86.4%, and in the case of discontinuities with depth equal or larger than 0.6mm with POD of 97%.

scholarly journals Experimental Studies of an Eddy Current Transducer with Spatially Periodic Fields

2018 ◽  
pp. 45-50
Author(s):  
B. Gorkunov ◽  
S. Lvov ◽  
Tamer Shaiban ◽  
Y. Borysenko
Keyword(s):  
Eddy Current ◽  
Experimental Studies ◽  
Fixed Frequency ◽  
Current Transducer ◽  
Current Conductor ◽  
Translation Symmetry ◽  
Spatially Periodic ◽  
Transducer Output ◽  
Angular Coordinates ◽  
Eddy Current Transducer

The purpose of this study is to perform a comparative analysis of the experimentally obtained and calculated values of the measuring windings total EMF amplitudes of the eddy current transducer with spatially periodic fields when magnetic and nonmagnetic cylindrical product are placed in it. To realize this goal in the work, a transducer with translational symmetry of excitation magnetic field has been developed. Translation symmetry typical example is the field of a long current conductor. The paper considers quasi-static electromagnetic field with the wavelength that exceeds characteristic transverse dimensions of conductor and cylinder. As the study result it is seen a satisfactory coincidence of the calculated and experimentally obtained values of the EMF of the transducer output signal in the cases of the product absence and with variety of products. As for example for measuring windings with angular coordinates φ = 30° and 60° an error of voltage values difference is less than 10%. The study shows that the advantage of such transducers while operating on one fixed frequency is capability to perform the multi-parameter testing on account of processing of certain amount of some spatial harmonics of excitation field.

scholarly journals Numerical Simulation of Non-Destructive Remote Field Eddy Current Testing of Rolled Metal Tubes

2019 ◽  
pp. 46-55
Author(s):  
A.G. Efimov ◽  
N.R. Kuzelev ◽  
E.V. Martyanov ◽  
B.M. Kanter ◽  
A.E. Shubochkin
Keyword(s):  
Numerical Simulation ◽  
Eddy Current ◽  
Current Method ◽  
Eddy Current Testing ◽  
Eddy Current Method ◽  
Current Testing ◽  
Advantages And Disadvantages ◽  
Current Transducer ◽  
Non Destructive ◽  
Eddy Current Transducer

The first publications describing the physical principles of the non-destructive remote field eddy current testing method appeared about 30 years ago. This method allows to significantly expand the field of application of eddy current testing. However, due to the lack of a theoretical justification, this method did not get widespread use around the world. Domestic publications in this area are completely absent, and the descriptions given in few foreign publications often contradict each other. There are no results of full-scale simulation using numerical methods in available domestic and foreign sources. The distinctive feature of this method under consideration is the ability of detecting defects on the external (with respect to the eddy current transducer) side of the tested object, which is impossible for the classical eddy current method due to the limited eddy current penetration depth. The basics of the method were considered, the distinctive features were presented, and the advantages and disadvantages of remote field eddy current testing of metals were pointed out. A numerical simulation with the subsequent analysis of the obtained results has been carried out, the transducer design for remote field eddy current testing is given. The influence of various factors on the change in the added voltage of the signal coil of the eddy current transducer in the presence of a defect in the external wall of the tube was considered. Expressions that determine the optimal ratio of the diameters of the transducer and the tested product were obtained. The values of the test parameters and the limiting wall thickness of the tested ferromagnetic product were determined.

A Working of Eddy Current Transducers under Control of Ferromagnetic Pipes in Condition of Insufficient Magnetic Saturation

2013 ◽  
Vol 467 ◽  
pp. 528-530
Author(s):  
Kai Yu Hao ◽  
Vadim Miroshnikov
Keyword(s):  
Electromagnetic Field ◽  
Numerical Calculation ◽  
Eddy Current ◽  
Maxwell Equations ◽  
Control Sample ◽  
Magnetic Saturation ◽  
Method Of Calculation ◽  
Current Transducer ◽  
Object Of Control ◽  
Eddy Current Transducer

The numerical method of calculation of electromagnetic field in a control sample at a time of work of encircling eddy current transducer is offered. The method is based on a numerical solution of the two Maxwell equations, which connect a change of electrical and magnetic fields. It allows to make calculations taking into account the actual value of magnetic inductivity of metal and to get results in any form, convenient for further interpretations. For the calculation of the encircling eddy current transducer the equivalent circuit of defect as step junction is offered. The numerical calculation shows, that the greatest sensitivity of the transducer is achieved when the value of magnetic permeability of the object of control is approximately 10-30. Therefore, it is not necessary to lead the material of the object of control up to satiety, as it considered before.

scholarly journals Eddy Current Transducer with Rotating Permanent Magnets to Test Planar Conducting Plates

Sensors ◽  
2019 ◽  
Vol 19 (6) ◽  
pp. 1408 ◽  
Author(s):  
Tomasz Chady ◽  
Jacek Grochowalski
Keyword(s):  
Magnetic Fields ◽  
Eddy Current ◽  
Permanent Magnets ◽  
Eddy Currents ◽  
Nonuniform Distribution ◽  
Current Transducer ◽  
Different Depths ◽  
Hall Sensors ◽  
Eddy Current Transducer

In this paper, we present an eddy current transducer with rotating permanent magnets for the inspection of planar conducting plates. The transducer consists of a rotating head with permanent magnets, which is used to generate variable magnetic fields and thus induce eddy currents in the tested material. Two Hall sensors connected in a differential manner are used to detect a nonuniform distribution of eddy currents induced in a specimen containing a defect. To prove the usability of the transducer, a number of experiments were conducted on thick aluminum samples containing notches at different depths. Selected results of the achieved measurements are presented.

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