Sensor of Current or Magnetic Field Based on Magnetoresistance Effect in (La0.7Ca0.3)0.8Mn1.2O3 Manganite Film

2009 ◽  
Vol 154 ◽  
pp. 157-161 ◽  
Author(s):  
V.P. Dyakonov ◽  
S. Piechota ◽  
K. Piotrowski ◽  
A. Szewczyk ◽  
H. Szymczak ◽  
...  

The main objective of the performed investigations was to enhance sensitivity of a current sensor to weak changes of magnetic field. New design of the sensor of current based on magnetoresistance effect – MRE (MRE = (RH - R0)/R0 , where RH is the resistance in magnetic field and R0 is the resistance without magnetic field) was developed. The sensor was produced in the form of an annular magnet with a gap, in which the (La0.7Sr0.3)0.8Мn1.2О3 manganite film possessing large negative MRE was inserted. Nominal current in a controllable electric circuit can change from a few tenths parts of ampere to a hundred of amperes. The limit detectable change of current value depends on the size of gap in the annular magnet. The operation time of sensor at current overload and short circuit is less than 0.3 sec. These magnetoresistors are thermally stable over the temperature range from (- 50 ° С) to (+ 50 ° С). Proposed sensors based on MRE can be applied in many electrical arrangements and devices.

2018 ◽  
Vol 7 (2) ◽  
pp. 36-39
Author(s):  
Galuh Lukitasari ◽  
Aad Hariyadi ◽  
Ridho Hendra Yoga Perdana

One of the communication technologies that can be used for monitoring current usage is communication technology via electric grids or what is called Power Line Communication (PLC). The advantages of this technology are that the electricity network is already distributed in each building so there is no need for new installations, it is economical and affordable in terms of economics, and is more practical and flexible in its use. In this study, a current usage monitoring system using PLC is proposed which will be applied in every class in the AI ??building of Malang State Polytechnic. The sensor that will be used in measuring the current value is the current sensor SCT-013. By using the KQ330 PLC module as a PLC transmission modem. The implementation of PLC which is applied in each class in the AI ??building has a BER (bit error rate) value of 0.012 in the experiment of sending 1000 data with an error of 12 times at the farthest distance of approximately 15 meters. And have a BER value of 0 or have no error in sending data at the closest distance of approximately 2-5 meters. In this study, the process of sending and receiving data using Power Line Communication allows it to be done at a distance that is not too far away to avoid excessive data errors.


A Current can be measured absolutely in the electro-magnetic system of units either by means of the action of the current on a magnet, or of the current on a current. The former method has the disadvantage that at least two independent measurements are necessary. For example, in using an electro-magnetic balance, the strength of the magnet acted on by the electric circuit has to be determined, as well as the force exerted on the magnet by the circuit. In galvanometers, either of the sine or tangent type, the magnetic field produced by the electric circuit is compared with the earth’s horizontal field, the strength of which is determined independently. Further, as the strength of artificial magnets cannot be regarded as truly constant, and the earth’s field is subject to diurnal and secular variations, this class of measurement is not ideal. In the electrodynamic class of measurement the mutual action between two or more coils carrying current takes the form of a torque, as in electrodynamometers, or a direct force, as in current weighers. In electrodynamometers the torque may be measured with a bifilar suspension, the torsion of a wire or spring, or by means of a gravity balance. Current weigher measurements are almost always made by direct comparison with gravity, which is believed to be constant, and is known to a higher degree of accuracy than the strengths of any magnet or magnetic field that has yet been measured.


1884 ◽  
Vol 12 ◽  
pp. 544-560 ◽  
Author(s):  
A. Tanakadaté ◽  
J. A. Ewing

The terrestrial magnetic field will in general be disturbed in the neighbourhood of an electric circuit; but if the circuit be a plane set at right angles to the terrestrial lines of force, the direction of the field will remain unchanged at all points in the plane of the circuit. To determine the magnetic meridian, we have only to place a plane circuit in such a direction that, when a current in the circuit is started and stopped, no change takes place in the position of a small magnet hung at a point in the plane of the circuit, and free to turn in azimuth. The plane of the circuit will then lie magnetically east and west.


Sensors ◽  
2018 ◽  
Vol 18 (7) ◽  
pp. 2231 ◽  
Author(s):  
Sungho Lee ◽  
Sungmin Hong ◽  
Wonki Park ◽  
Wonhyo Kim ◽  
Jaehoon Lee ◽  
...  

In this paper, we propose a high accuracy open-type current sensor with a differential Planar Hall Resistive (PHR) sensor. Conventional open-type current sensors with magnetic sensors are usually vulnerable to interference from an external magnetic field. To reduce the effect of an unintended magnetic field, the proposed design uses a differential structure with PHR. The differential structure provides robust performance to unwanted magnetic flux and increased magnetic sensitivity. In addition, instead of conventional Hall sensors with a magnetic concentrator, a newly developed PHR with high sensitivity is employed to sense horizontal magnetic fields. The PHR sensor and read-out integrated circuit (IC) are integrated through a post-Complementary metal-oxide-semiconductor (CMOS) process using multi-chip packaging. The current sensor is designed to measure a 1 A current level. The measured performance of the designed current sensor has a 16 kHz bandwidth and a current nonlinearity of under ±0.5%.


Author(s):  
Ovidiu CRAIU ◽  
Leonard-Marius MELCESCU ◽  
Teodor-Ionut ICHIM

"This paper presents a computer-aided-design (CAD) of a dumping coil of an actuator producing a limited angular displacement proportional to intake current. Initially, a 2D FEM magnetic field model was developed for studying and optimizing the actuator. Subsequently, the model was coupled with the dumping coil short circuit and mechanical motion equations describing the dumping process. The rotor dumping was analyzed by modelling the rotor movement from the maximum angle position to zero under spring load action, when no current passes through field coil. Several practical aspects regarding numerical model built in COMSOL Multiphysics v5.3 are also presented. Paper purpose: Describing the optimization process of an actuator with limited angle, as well as implementing a magnetic field FEM model coupled with electric circuit and mechanical movement equations. Elements of originality: 1. Developing a complex numerical FEM model coupled with electric circuit and movement equations. 2. Practical interpretation of the results and experience gained in using such damping solutions for limited angle actuators."


Author(s):  
Way-Jam Chen ◽  
Lily Shiau ◽  
Ming-Ching Huang ◽  
Chia-Hsing Chao

Abstract In this study we have investigated the magnetic field associated with a current flowing in a circuit using Magnetic Force Microscopy (MFM). The technique is able to identify the magnetic field associated with a current flow and has potential for failure analysis.


2020 ◽  
Vol 96 (3s) ◽  
pp. 295-299
Author(s):  
М.М. Гурарий ◽  
М.М. Жаров ◽  
Л.П. Ионов ◽  
И.И. Мухин ◽  
С.Г. Русаков ◽  
...  

В работе рассмотрены проблемы анализа схем ФАПЧ с учетом наличия неидеальностей в схеме частотно-фазового детектора с токовым ключом. Для снижения затрат на моделирование предложено использовать эквивалентную электрическую схему, содержащую полную принципиальную схему ЧФД и схемные эквиваленты макромоделей остальных блоков ФАПЧ. The paper considers the problems of analyzing the PLL circuit taking into account the presence of nonidealities in the phase-frequency detector with a current key. To reduce the simulation efforts, it has been proposed to apply an equivalent electric circuit containing the complete schematic diagram of the PFD and circuit equivalents of the macromodels of other PLL blocks.


Author(s):  
Aleksandr S. Serebryakov ◽  
Vladimir L. Osokin ◽  
Sergey A. Kapustkin

The article describes main provisions and relations for calculating short-circuit currents and phase currents in a three-phase traction transformer with a star-triangle-11 connection of windings, which feeds two single-phase loads in AC traction networks with a nominal voltage of 25 kilovolts. These transformers provide power to the enterprises of the agro-industrial complex located along the railway line. (Research purpose) The research purpose is in substantiating theoretical equations for digital intelligent relay protection in two-phase short circuits. (Materials and methods) It was found that since the sum of instantaneous currents in each phase is zero, each phase of the transformer works independently. We found that this significantly simplifies the task of analyzing processes with a two-phase short circuit. In this case, the problem of calculating short-circuit currents in the traction network can be simplified by reducing it to the calculation of an ordinary electric circuit with three unknown currents. (Results and discussion) The article describes equations for calculating short-circuit resistances for one phase of the transformer when connecting the secondary winding as a star or a triangle. The currents in the phases of the transformer winding at short circuit for the star-triangle-11 and star-star-with-ground schemes are compared. It was found that when calculating short-circuit currents, there is no need to convert the secondary winding of the traction transformer from a triangle to a star. (Conclusions) It was found that the results of the research can be used in the transition of relay protection systems from electromagnetic relays to modern high-speed digital devices, which will increase the operational reliability of power supply systems for traction and non-traction power consumers.


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