Papers by Keyword: Electromagnetic Induction

Abstract: This article discusses the results of work on the creation of a flaw detection unit, which is focused on the study of high-strength steels. Welded joints of transformer tanks, which are made of steel grade 08G2B, were selected as the object of research. We chose this grade because of the ultra-low carbon content of this material. This opens up opportunities for the application of eddy current nondestructive testing methods. For practical measurements, a scanning device was designed and optimized. It includes a converter that uses the principles of eddy currents and includes three coils assembled on a ferrite core, grade 80NMZ. The device was tested on samples with model continuity defects (cracks and holes). Also, within the framework of the publication, modeling of corrosion defects in welded joints was carried out.

Abstract: In the paper, the behavior of an impactor penetrating through a polymer sheet was measured using electromagnetic induction phenomena. First, electromotive forces generated in a coil were measured to decide the relation between the impactor velocity and the electromotive force when the impactor with an embedded neodymium magnet passed through a coil at several constant velocities. The intensity of the electromotive force was found to be proportional to the impactor velocity at each impactor position. The relation was used as the calibration data to calculate the velocity and position of the impactor. Next, penetration tests of polyvinyl chloride sheets were conducted with the coil set at the front of the sheet. The electromotive force generated in the coil was measured when the impactor penetrated through the sheet. The impactor velocity and position were calculated from the electromotive force with the calibration data. The validity of the measuring method was confirmed because the calculated results from the measured electromotive force agreed with the observed results by using a high speed video camera.

Abstract: An instrument based on electromagnetic induction method for detecting magnetic material in soil subsurface has been developed. The instrument consists of a signal generator, an amplifier, a transmitter, receivers, detectors and a display. A coil is used as transmitter. As receiver and also detector is used a three dimensional self-developed fluxgate sensor. The fluxgate sensor consists of two pick-up coils, four excitation coils, and a ferromagnetic core. The output voltage of the sensor is processed using an analog signal processing circuit. The sensor’s capability in detecting magnetic material in the soil subsurface was observed by placing a sample of magnetic material in the subsurface, and then detected using fluxgate sensor in the direction of the x, y and z (3D). We found that the developed instrument is capable to detect two different objects that is separated at minimum distance around 10 cm with the maximum shallow depth of the target material is 10 cm.

Abstract: This paper presents two electromagnetic vibration energy harvesters based on micro-electro-mechanical (MEMS) technology. Two prototypes with different vibration structures were designed and fabricated. The energy harvester includes a permanent magnet attached on vibration structure (resonator) made by Si and a fixed wire-wound coil, with the total volume of 0.9 cm³. Two energy harvesters with different resonator are tested and compared. Experiments show that: in the same acceleration and a load resistance, the resonant frequency of prototype B is approximately 95% of prototype A; The peak-peak voltage and the maximum power of prototype B is 1.6 times and 2.7 times of prototype A respectively. The test results was analyzed simply and it indicated that the electromagnetic energy harvesting with the spring B has better performance; also proved that the potential ability of the non-linear spring could extend the frequency bandwidth and improve output voltage.

Abstract: In this paper a new drip-and leakage-free method for the electromagnetic levitation melting of metallic samples with greater weights, stabilized position and free surface shape is presented. The method can be used in a melting furnace, as well as for the coreless induction valves applied for the flow rate control, e.g. in the continuous casting of molten metals.The applicability of the method was examined numerically and experimentally proved by tests conducted with different types of laboratory setups.

Abstract: Advances in medical technology and promote the human implantable wireless energy transfer devices are widely used. Traditional human implantable wireless energy transfer device have some problems of low charging efficiency, blindly charging and data transmission difficult. On the basis of the conventional electromagnetic induction, in this paper, we proposed the use of magnetically coupled resonant way on human implantable device for charging, this method can greatly improve the efficiency of wireless charging. The system gets the CPU’s unique ID of human implantable devices to identifying the device. We can artificially control human implantable device’s charging device number, so as to solve the problems caused by the blind charge. Meanwhile, the system uses an electromagnetic carrier approach for data transmission, both to simplify the complexity of hardware devices and improve the communication efficiency of the device.

Abstract: Using the principle of electromagnetic induction, we designed the new rotary transformer device which secondary winding can rotate with the prime mover. The device not only achieves the purpose that provides synchronous generator with AC power of exciting side, but also can eliminate the impact of slip ring and carbon brushes fundamentally on the system. The test results of the prototype also show that the design of the rotary transformer described herein is possible.

Abstract: The electromechanical interaction between electromagnetic wave and the electric current system is a fundamental problem in electrodynamics.However, for particular parameters of electromagnetic wave and The electric current system, Through the electromagnetic interaction，there may be some significant physical effects depended on the Effective electromagnetic force, The systematic and thorough study is of great significance for the advance of electromagnetic theory and microwave technology.

Abstract: Dynamics of projectile penetration into sand depends greatly on the features of motion and state of the sand material at the interface with the projectile. The goal of this study is to clarify the behavior of projectile during penetration under the impulse loading induced by the plate impact using a vertical powder gun. In this paper, we constructed an accurate and reliable technique for measuring projectile penetration velocity into sand. “Magnet-Coil” gage method was suggested on the basis of electromagnetic induction phenomena due to movement of the projectile having magnet. We confirmed that it has sufficient measurement accuracy.

Abstract: Aimed at the disadvantage of traditional magnetic detection such as susceptible to magnetic interference and positioning not accurate, the paper presents an algorithm of passive route detection and localization of armored optical fiber cable based on the pulse induction. By injecting changing current to the detection coil, the algorithm used induction technology to incentive out the induction voltage in metallic materials of the detected armored optical fiber cable and established the model about the distance between them. Then derived that the impact of the armored optical fiber cable on the coil voltage was in reverse proportion to the distance six powers of exponent. In addition , the algorithm used coil array to detect and localize the cable to determine the position of the armored optical fiber cable. The results of the simulation indicates the effectiveness of the presented algorithm and passive route detection system and provides feasible ideas to make the technology of passive route detection of armored optical fiber cable practical on the next step.