Experimental research of the influence of a ferromagnetic core on the speed of an induction-dynamic release with turning anchor type

Circuit breakers for overcurrent protection of semiconductor converters limit the duration and amplitude of the overcurrent at such a level that its thermal effect does not exceed the maximum allowable thermal protection index of the protected semiconductor device. The limitation of the thermal action of the short-circuit current is achieved by reducing the operation time of the circuit breaker. The design of the circuit breaker is changed in such a way that instead of the basic electromagnetic release is used an induction-dynamic release, which consists of an inductor with a ferromagnetic core and a rotary armature in the form of a copper disk. The electrodynamic force producing by the induction-dynamic release for quick operation is determined by the coefficient of mutual inductance of the inductor coil and the armature. Using of a ferromagnetic core entailed an increase in the coefficient of mutual inductance of the coil and armature, therefore, an increase in the electrodynamic force producing by the release, and a decrease in own tripping time of the circuit breaker. On a prototype, an experimental study of the proper operation time of the release was carried out at various values of the electrical parameters of the capacitor bank of the inductor power supply, the winding parameters of the inductor coil and the disk dimensions. The research results have proved both a decrease in the tripping time of the circuit breaker while conserving the energy of the capacitor bank of the inductor, and a decrease in the required energy of the capacitor bank to power the inductor while maintaining the minimum tripping time of the circuit breaker. Reducing the energy of the capacitor bank of the inductor made it possible to reduce the capacity and voltage of the capacitor bank of the supply of the release, and, consequently, its dimensions.

Inductor coil of the highest possible $$\mathbf {Q}$$

The geometry of an inductor made of a long thin wire and having the highest possible Q-factor is found by numerical optimization. As frequency increases, the Q-factor first grows linearly and then according to a square-root law, while the cross-section of the optimal coil evolves from near-circular to sickle-shaped.

Analysis of the Performance Variation Mechanism of MEMS Suspended Inductors under Mechanical Shock

Micro-electromechanical system (MEMS) suspended inductors have been widely studied in recent decades because of their excellent radio frequency performance. However, the deformation of the inductor coil and the performance variation usually occur to the MEMS suspended inductors when the inductors are under mechanical shock. Few studies have been carried out on the performance variation of MEMS suspended inductors under shock. In this study, the mechanism of the performance variation of MEMS suspended inductors under mechanical shock is analyzed by combining theoretical analysis and experiments. A theoretical analysis based on the lumped-element equivalent model is presented and shock tests are carried out. The shock tests show that the main reason of the MEMS suspended inductor performance variation after mechanical shock is the variation of the substrate parasitic effect, which is caused by the variation of the suspension height of the inductor after shock. The test results agree with the theoretical analysis.

ANALISIS PARAMETER MIKROSTRUKTUR NANOPARTIKEL Mn1-xZnxFe2O4 BERDASARKAN POLA DIFRAKSI SINAR X

The Mn-Zn Ferit is a magnetic material which has potential applications for data storage device, the inductor coil and catalysis. This material has unique electrical and optical properties. Their properties are microstructural dependent. In this work, we studied the microstructural parameters of Mn1-xZnxFe2O4 which x assigns the mole fraction of Mn2+ and Zn2+ (x = 0.6; 0.7 and 0.8). Samples were synthesized by using coprecipitation method and NaOH as a coprecipitant. Microstructural parameters were investigated based on X-ray diffraction pattern. The crystallite size and strain were determined by using Size-strain plot (SSP) method. The crystallite size of nanoparticles is in a range of 18.9 nm – 24.8 nm, while the strain is in a range of 0.0012 – 0.0099. The lattice parameter is in a range of 8.531Ǻ - 8.567Ǻ bigger than the values were calculated theoretically according to the theoretical cation distribution model. The cation distribution in crystal lattice takes important rule in determining the microstructural parameters of nanoparticles.

Method of Calculating the Inductance Value of MEMS Suspended Inductors with Silicon Substrates

Microelectromechanical system (MEMS) suspended inductors have excellent radio-frequency (RF) performance. The inductance value is one of the main features that characterizes the performance of inductors. It is important to consider the influence of the substrate and the suspension height in calculating the inductance value accurately. In this paper, a method is proposed to calculate the inductance value of the MEMS suspended inductor wire with a silicon substrate, as the wire is the basic component of the inductor coil. Then the method is extended to the suspended inductors consisting of a single turn coil. The calculation results obtained by this proposed method were verified by finite-element analysis (HFSS) and they were found to agree well with the results of the HFSS simulation.

Werkstückerwärmung für das Thixoforming*/Heating workpieces for Thixoforming - Using inductor as sensor for monitoring the heating process of semi-solid material

Das Thixoforming nutzt bei der Formgebung besondere Materialeigenschaften zur Herstellung metallischer Bauteile. Die verwendeten Legierungen müssen dazu in den sogenannten teilflüssigen Bereich erwärmt werden. Das Einstellen des geforderten Fest-Flüssig-Verhältnisses stellt besondere Anforderungen an die Erwärmung. Betrachtet werden verschiedene Messverfahren, welche die Induktorspule bei der induktiven Erwärmung als Sensor nutzen.   Thixoforming uses specific material properties for shaping metal workpieces. For this purpose, the alloys need to be heated to the so-called semi-solid state. The adjustment of the desired semi-solid fraction imposes high requirements on the heating process. Various measurement principles, which use the inductor-coil as a sensor in inductive heating processes, are presented.

Inductive Sensing to Detect Tissue Thickness Between Magnets for Potential Application in Magnetic Compression Based Anastomosis

Magnetic compression based anastomoses use magnetic force to necrose tissue between two magnets to create an anastomosis. Nickel-plated neodymium–iron–boron magnets are used in our study. The compression pressure between the magnets depends on the distance between the magnets, which is determined by the thickness of the compressed tissue and depends on bowel wall thickness and elasticity. It is critical to know the distance between the magnets once the tissue is compressed because the magnets must be within a critical distance of each other in order to create enough compressive force to necrose the tissue. We have developed an inductance sensor to detect the distance (tissue thickness) between the two magnets after the surgeon has deployed them. Inductance sensing is a contact-less sensing method that enables precise short-range detection of conducting surfaces. The inductor coil mounted on one magnet detects the second magnet by measuring the change in inductance due to eddy current induced on the nickel-plated surface of the second magnet. The change in the inductance is proportional to the change in distance between the magnets. The sensor was first calibrated by using polycarbonate sheets to simulate the intestine tissue. We are able to detect up to 6 mm of spacing between the magnets. Pig intestine from Yorkshire pigs was used to characterize the sensor. We are able to distinguish up to five distinct layers of the intestine from the large intestine. This sensing mechanism can indicate the operating surgeon the exact thickness of the tissue compressed between the two magnets. The surgeon can thus be sure of formation of a clean anastomosis and avoid the likelihood of the magnets sliding away or uncoupling.

The Research on Electroplating Technology Used for RF Micro Inductor Coil

In this paper, we focus on the electroplating technology used for RF micro inductor coil. The technological parameters in DC electroplating are determined by SEM, linear sweep voltammetry and so on. It turns out that a high quality of plating layer is obtained when the PH value of electrochemical solution is 9, temperature is 45°C,current density is 1 A/dm2, additive is added and stirred slowly. Then the research on pulse electroplating is conducted on the basis of DC electroplating, and the result indicates that the pulse plating layer is of better quality compared with DC plating layer. Afterwards, surface structure and resistance of the copper layer are analyzed, demonstrating the obtained coating layer is good enough to be the main structure of micro inductor coil. In the end, this electroplating technology is applied to micro inductor coil. The simulation, fabrication, package and test of micro inductor coil are introduced briefly.