scholarly journals A Novel Breaking Strategy for Reduced Response Time of Electromagnetic Contactor by Reverse Voltage Application

Energies ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 789 ◽  
Author(s):  
Shuhua Fang ◽  
Yong Chen ◽  
Haimiao Ni ◽  
Heyun Lin ◽  
Xingang Wang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Response Time ◽  
Iron Core ◽  
Dramatic Reduction ◽  
Reverse Voltage ◽  
Excitation Coil ◽  
Voltage Application ◽  
Source Voltage ◽  
Drive Circuit ◽  
The Magnetic Field

This paper proposes a novel breaking strategy for dramatically shortening the response time of a single, stable electromagnetic contactor. A reverse voltage was applied across the excitation coil to increase the decay velocity of the magnetic field in the iron core, leading to a dramatic reduction of the electromagnetic force when the contactor initiated the breaking process. The applied time of the reverse voltage was determined by numerical computation of circuit, magnetic field, and forces. The polarity of source voltage was overturned by controlling switching devices in the bridge drive circuit. A co-simulation coupling magnetic field, machinery, and circuit was carried out using Maxwell and Circuit Editor software. Experimental results are reported to demonstrate the effectiveness of the proposed breaking strategy for shortening the response time of an electromagnetic contactor.

scholarly journals Magnetorotational supernovae with different equations of state

2011 ◽  
Vol 7 (S279) ◽  
pp. 357-358
Author(s):  
Sergey G. Moiseenko ◽  
Gennady S. Bisnovatyi-Kogan
Keyword(s):  
Magnetic Field ◽  
Shock Wave ◽  
Angular Momentum ◽  
Differential Rotation ◽  
Equations Of State ◽  
Supernova Explosion ◽  
Explosion Energy ◽  
Iron Core ◽  
Wave Forms ◽  
The Magnetic Field

AbstractWe present results of the simulation of a magneto-rotational supernova explosion. We show that, due to the differential rotation of the collapsing iron core, the magnetic field increases with time. The magnetic field transfers angular momentum and a MHD shock wave forms. This shock wave produces the supernova explosion. The explosion energy computed in our simulations is 0.5-2.5 ċ 1051erg. We used two different equations of state for the simulations. The results are rather similar.

scholarly journals A dynamic simulation of the circuit breaking electromagnetic system with a drive circuit

2019 ◽  
Vol 11 (3) ◽  
pp. 168781401982856
Author(s):  
Shize Huang ◽  
Fan Zhang ◽  
Yue Liu ◽  
Qiyi Guo
Keyword(s):  
Magnetic Field ◽  
Dynamic Simulation ◽  
Dynamic Characteristics ◽  
Simulation Method ◽  
Digital Controller ◽  
Electromagnetic System ◽  
Switching Device ◽  
Dynamic Analyses ◽  
Drive Circuit ◽  
The Magnetic Field

A circuit breaking electromagnetic system is the actuator and digital controller for a switching device. Its performance can significantly affect operations of the switching device. We propose a dynamic simulation method coupling the electric field and the magnetic field for the circuit breaking electromagnetic system and its drive circuit. The method combines both statistic and dynamic analyses, and differential equations. Finally, we utilize the flux transformer as an example to validate this method and reveal the dynamic characteristics of the drive transformer by changing the parameters of the drive circuit.

Experimental Investigation of the Transient Behavior of MR Fluids

2011 ◽  
Author(s):  
Ju¨rgen Maas ◽  
Dirk Gu¨th
Keyword(s):  
Magnetic Field ◽  
Experimental Investigation ◽  
Response Time ◽  
Dynamic Properties ◽  
Transient Behavior ◽  
Current Control ◽  
Large Signal ◽  
Carrier Fluid ◽  
Mr Fluids ◽  
The Magnetic Field

The transient behavior of MRF actuators is an important property for certain applications that is mainly affected by three delays, occurring from the dynamic properties of the coil current, the magnetic field and the torque generation by the MRF. In order to investigate the transient behavior of the generated torque with respect to the magnetic field, which is mainly affected by the motion of the MR particles in the carrier fluid, the mentioned response time of the electrical and magnetic domains must be in an appropriated ratio in comparison to the MRF response time to obtain reliable results by experiments. Therefore a special disc-type test actuator with outstanding dynamics is designed that minimizes the delays by the use of an ultrafast current control and a magnetic core made of soft ferrite material for preventing the effects of eddy currents. For the experimental investigation of the transient behavior of MR fluids, the small signal as well as the large signal behavior is analyzed for different test signals and load conditions of the actuator. Various results of the investigated transient behavior are shown finally for two different MR fluids featuring response times of about 1 ms for the fluid itself and switching times of about 4 ms for the MRF actuator.

scholarly journals Reduction of Coil-Crack Angle Sensitivity Effect Using a Novel Flux Feature of ACFM Technique

2021 ◽  
Author(s):  
Ruochen Huang ◽  
Mingyang Lu ◽  
Ziqi Chen ◽  
Wuliang Yin
Keyword(s):  
Magnetic Field ◽  
Crack Detection ◽  
Sine Wave ◽  
Destructive Testing ◽  
Computation Efficiency ◽  
Detection Approach ◽  
Excitation Coil ◽  
Lift Off ◽  
The Magnetic Field ◽  
Sensor Probe

Alternating current field measurement (ACFM) testing is one of promising techniques in the field of non-destructive testing with advantages of the non-contact capability and the reduction of lift-off effects. In this paper, a novel crack detection approach is proposed to reduce the effect of the angled crack (cack orientation) by using rotated ACFM techniques. The sensor probe is composed of an excitation coil and two receiving coils. Two receiving coils are orthogonally placed in the centre of the excitation coil where the magnetic field is measured. It is found that the change of the x component and the peak value of the z component of the magnetic field when the sensor probe rotates around a crack follows a sine wave shape. A customised accelerated finite element method solver programmed in MATLAB is adopted to simulate the performance of the designed sensor probe which can significantly improve the computation efficiency due to the small crack perturbation. The experiments have also been carried out to validate the simulations. It is found that the ratio between the z and x components of the magnetic field remains stable under various rotation angles. It shows the potential to estimate the depth of the crack from the ratio detected by combining the magnetic fields from both receiving coils (i.e., the x and z components of the magnetic field) using the rotated ACFM technique.

INVESTIGATING THE TIME DEPENDENCE OF THE MR EFFECT

2007 ◽  
Vol 21 (28n29) ◽  
pp. 4832-4840 ◽  
Author(s):  
FERNANDO D. GONCALVES ◽  
J. DAVID CARLSON
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Response Time ◽  
Time Dependence ◽  
Dwell Time ◽  
High Shear ◽  
Proposed Model ◽  
Mr Effect ◽  
The Magnetic Field ◽  
Field Strengths

Magnetorheological fluids are known to respond in a matter of milliseconds to the application of a magnetic field. To date, however, very little work has been done to study the time dependence of the MR response. The purpose of this study is to investigate the response time of the fluid. Experiments were conducted on a high shear rate rheometer capable of fluid speeds in excess of 35 m/s. With an MR valve length of 6.35 mm, the resulting dwell times were as low as 0.18 ms. For each of three magnetic field strengths, a reduction in yield stress is observed as dwell time decreases. A model is proposed to represent the time response of the fluid to the application of the magnetic field. The experimental data and the proposed model are used to identify the response time of the fluid for each field strength. Results indicate that as the magnetic field increases, the response time of the MR fluid decreases. For the range of magnetic field strengths considered in this study the response time of the fluid ranged from 0.24 ms to 0.19 ms.

A Novel Active Online Electromagnetic Balancing Method—Principle and Structure Analysis

2012 ◽  
Vol 134 (3) ◽  
Author(s):  
Shilei Ma ◽  
Shiyuan Pei ◽  
Lin Wang ◽  
Hua Xu
Keyword(s):  
Magnetic Field ◽  
Electromagnetic Force ◽  
Magnetic Force ◽  
Cutting Tools ◽  
Field Analysis ◽  
Iron Core ◽  
Machining Processes ◽  
Magnetic Field Analysis ◽  
Precision Finishing ◽  
The Magnetic Field

Vibrations caused by the imbalance of a rotor are a frequently encountered problem in machining processes. Especially in high-precision finishing, the workpiece quality is strongly related to the vibration of the machine-tool spindle, which is mainly caused by mass imbalance and cannot be completely eliminated in cutting tools with nonaxisymmetrical structures. An imbalance in centrifugal force is generated by rotor rotation and increases rapidly with rotational speed. A novel active online electromagnetic balancing method based on static magnetic-field analysis is proposed, and an active online electromagnetic balancing device (AOEBD) based on this method was developed under these conditions. The magnetic-field distribution and electromagnetic force generated by the device were analyzed by finite-element modeling. The influence on the electromagnetic force of the misalignment between the rotor and the iron core was investigated. Factors influencing the magnetic force of the device were determined, and reasonable reference values were suggested. The critical eccentricity was also provided. Experiments had been done at last, and the experimental results presented a good performance of this kind of balancing device.

scholarly journals Development of Digital Scale Based on Fluxgate Sensor

2016 ◽  
Vol 1 ◽  
Author(s):  
Mitra Djamal
Keyword(s):  
Magnetic Field ◽  
Relative Error ◽  
Output Voltage ◽  
Absolute Error ◽  
Maximum Relative Error ◽  
Maximum Absolute Error ◽  
Sensor Development ◽  
Fluxgate Sensor ◽  
Excitation Coil ◽  
The Magnetic Field

<p>Fluxgate is a magnetic sensor which works by comparing the measurement magnetic field with the magnetic field reference. This research aims to develop digital scales using fluxgate sensor. The steps involved were sensor development, characterization, distance and mass calibration of the fabricated sensor. Here, a digital scale based on fluxgate sensor with oval vitrovac 6025Z type core, 360 windings of excitation coil and 240 windings of pick up coil was successfully fabricated. Characterization result shows that the sensor has 1669.2 mV/μT sensitivity and working area of about ± 1.9 μT, with maximum absolute error found out to be around 0.0573 μT with maximum relative error is 1.464 %. Calibrated sensor value obtained reveals that the sensor works from 15.86 until 27.00 mm in distance, utilizing equation of relationship between mass and output voltage  with the maximum relative error obtained as low as 1.49 %.</p>

Calibration Procedure for Magnetization Loop Tracers

2013 ◽  
Vol 543 ◽  
pp. 472-475
Author(s):  
Vasiliki Roussi ◽  
Clio G. Vossou
Keyword(s):  
Magnetic Field ◽  
Coming Out ◽  
Calibration Procedure ◽  
The Finite Element Method ◽  
Vertical Array ◽  
Steel Sheets ◽  
Excitation Coil ◽  
Set Up ◽  
Electrical Steel Sheets ◽  
The Magnetic Field

The purpose of this paper is to calibrate the magnetic field coming out of an excitation coil of certain specifications, fabricated for non-destructing testing of electrical steel sheets. Thus, a comparison between experimental and numerical analysis is discussed. For the experimental estimation of the magnetic field, a sensitive Hall sensor is used to measure the dc field at a vertical array of three selected points inside the coil. These are the lower, the middle and the upper point of the coil cross section, respectively. The magnetic field is then computed theoretically using the finite element method and the BiotSavart law. Measured results are in agreement with the calculated results of the excitation field very well, within the limits of our experimental set-up.

scholarly journals Development of Digital Scale Based on Fluxgate Sensor

2016 ◽  
Vol 1 (1) ◽  
Author(s):  
Mitra Djamal
Keyword(s):  
Magnetic Field ◽  
Relative Error ◽  
Output Voltage ◽  
Absolute Error ◽  
Maximum Relative Error ◽  
Maximum Absolute Error ◽  
Sensor Development ◽  
Fluxgate Sensor ◽  
Excitation Coil ◽  
The Magnetic Field

<p>Fluxgate is a magnetic sensor which works by comparing the measurement magnetic field with the magnetic field reference. This research aims to develop digital scales using fluxgate sensor. The steps involved were sensor development, characterization, distance and mass calibration of the fabricated sensor. Here, a digital scale based on fluxgate sensor with oval vitrovac 6025Z type core, 360 windings of excitation coil and 240 windings of pick up coil was successfully fabricated. Characterization result shows that the sensor has 1669.2 mV/μT sensitivity and working area of about ± 1.9 μT, with maximum absolute error found out to be around 0.0573 μT with maximum relative error is 1.464 %. Calibrated sensor value obtained reveals that the sensor works from 15.86 until 27.00 mm in distance, utilizing equation of relationship between mass and output voltage  with the maximum relative error obtained as low as 1.49 %.</p>

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