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Electromagnetic force is a very important parameter for push-pull solenoids, but it is difficult to calculate analytically due to the nonlinear variation of the magnetic field. Aiming at this problem, To address this problem, the use of magnetic vector potential theory in a columnar coordinate system was investigated to solve the electromagnetic force of a cylindrical push-pull electromagnet. The whole solenoid magnetic field was divided into several sub-domains and the boundary conditions were defined to obtain the sub-domain magnetic vector equations which can be solved numerically, and then the electromagnetic characteristic data such as magnetic vector potential, inductance and electromagnetic force were calculated by MATLAB programming. Comparing the two cases of B-H curves of iron core permeability in finite element with constant value of 10 000 and electric soft iron respectively, the calculation accuracy and error variation trend of this numerical algorithm were illustrated, and the reason for the formation of the error were analyzed. With the increase of current the core will be magnetically saturated, when the magnetic saturation problem is not serious, the calculation result of numerical algorithm has high accuracy. With the increase of current, the error increases rapidly after the core is magnetically saturated. In the experiment, different sizes of excitation currents were applied to the cylindrical push-pull electromagnet, and the output thrust results obtained were consistent with theoretical analysis. [ABSTRACT FROM AUTHOR]

The Angular Spectrum Representation (ASR) is applied to describe semi-analytically the optical force densities acting on linear dielectric media when a quasi-monochromatic tightly focused Gaussian beam is applied. This method is seen to be inherently faster than conventional finite-difference schemes. Numerical simulations of the optical force densities were also performed and found to be in agreement with the literature, providing a complementary tool for the study of opto-mechanical effects in matter. [ABSTRACT FROM AUTHOR]

Copyright of Electric Machines & Control / Dianji Yu Kongzhi Xuebao is the property of Electric Machines & Control and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Magnetic Pulse Welding (MPW) process uses only electromagnetic force to create a solid-state metallurgical bond between a working coil and outer workpiece. The electromagnetic force drives the outer tube to collide with the inner rod, resulting in successful bonding. However, due to the dissimilarity of the MPW joint, only a portion of the interface forms a metallurgical bond, which affects the quality of the joint. Therefore, the purpose of this study is to analyze the effects of process parameters on joint quality through experimental work using RSM. Furthermore, an optimization algorithm is utilized to optimize the process parameters used in magnetic pulse welding. A1070 aluminum and S45C carbon steel were used as the materials, while peak current, gap between working coil and outer tube, and frequency were chosen as the process parameters for MPW. The welding conditions are determined through experimental design. After welding, the maximum load and weld length are measured to analyze the effect of the process parameters, and a prediction model is developed. Specifically, to achieve a high-quality joint, the process parameters are optimized using the Imperialist Competitive Algorithm (ICA) and Genetic Algorithm (GA). The results reveal that the peak current is a significant parameter, and the developed prediction model exhibits high accuracy. Furthermore, the ICA algorithm proves very effective in determining the process parameters for achieving a high-quality Al/Steel MPW joint. [ABSTRACT FROM AUTHOR]

The magnetic suspension damper, which is based on magnetic suspension technology, is receiving more and more attention from academics as active–passive hybrid damping technology develops. A new symmetric magnetic suspension structure is constructed in this study, and the accuracy of the simulation findings is confirmed by contrasting the output from finite element simulation with the theoretical formulations. On the basis of this, how the structure, size, and material of the electromagnet and armature affect the magnetic flux density, electromagnetic force, and suspension force is investigated. The structure optimization of the electromagnet and armature was performed in accordance with the simulation results, and a new symmetric magnetic suspension structure was produced. The results of the simulation demonstrate that DT4(electrical pure iron) is the ideal material for armatures and electromagnets. The reinforcing ring construction can be built up by the armature to increase suspension force. The suspension force output by the armature will be greatly increased when the size and placement of the reinforcing ring structure are right. The system stiffness adjustment range will expand at this point, enhancing the magnetic suspension damper's functionality. This study offers novel perspectives for designing structures that reduce vibration and noise in various projects and serves as a guide to constructing magnetic suspension dampers. [ABSTRACT FROM AUTHOR]

Abstract A new inhibition method was proposed for the problem of harmonic of radial electromagnetic force during the operation of the composite magnetic coupler. In order to suppress its radial electromagnetic force, a radial permanent magnet rotor eccentricity method is proposed, and a three‐dimensional finite element model is established. Based on the Maxwell tensor method, the radial electromagnetic force of the composite magnetic coupler is analysed, and the mathematical expression of its radial electromagnetic force is established, Maxwell stress tensor was used to analyse the radial electromagnetic force in a composite magnetic coupler and to establish the mathematical equation for the radial electromagnetic force. In order to suppress the radial electromagnetic force, a method based on rotor eccentricity in a radial permanent magnet was proposed. A prototype of a composite magnetic coupler with a rated power of 5 kW was designed to test its output torque under load. The results showed that the simulated curve was consistent with the tested curve, with a maximum numerical error of 8.9%. The tested values of the output torque before and after eccentricity were compared, and the results showed that the output torque remained basically unchanged after the eccentric structure was adopted and that the torque pulsation was significantly reduced.

Given the frequent adhesion of vertically arranged double-split conductors， the research on adhesion is of practical significance. The fault of 220 kV lines is taken as an example to establish an adhesion model of the double-split model based on the conductor state equation and electromagnetic force calculation to study the impact of wire temperature， wind speed， DC resistance error， tension， and other factors on conductor adhesion. The study shows that the critical current of the conductor adhesion increases as the conductor temperature rises and decreases with the increase of the tension， sub-conductor resistance error， and wind speed. Under the interaction of resistance and wind speed， the critical current reaches its minimum in the case of the maximum resistance error value and the minimum wind speed. The research results can provide a useful reference for line design and modification.

Electromagnetic forces generated by the short circuit current and leakage flux in low- and high-voltage windings of distribution transformers as well as amorphous core transformers will cause the translation, destruction, and explosion of the windings. Thus, the investigation of these forces plays a significant role for researchers and manufacturers. Many authors have recently used the finite element method to analyze electromagnetic forces. In this paper, an analytic model is first developed for magnetic vector potential formulations to compute the electromagnetic forces (i.e., axial and radial forces) acting on the low- and high-voltage windings of an amorphous core transformer. The finite element technique is then presented to validate the results obtained from the analytical model. The developed model is applied to an actual problem.

This article presents a detailed analysis of the electromagnetic force and vibration behavior of a new axial flux permanent magnet (AFPM) machine with a yokeless stator and interior PM rotor. Firstly, the configuration of an AFPM machine with a dual rotor and a sandwiched stator is introduced, including the structural design, fixation of the yokeless stator and segmented skew rotor structure. Then, the influence of anisotropic material and a fixed structure on stator modes is analyzed, including elastic modulus, shear model, the skew angle of slot and the thickness of stator yoke. Furthermore, a new non-equally segmented skew rotor structure is proposed and calculated for the reduction in vibration based on the multiphysics model. Three different segmented skew rotor schemes are compared to illustrate the influence of reducing vibration and noise. The predicted results show that the effect of the non-equally segmented skew rotor on reducing vibration is better than the other two schemes. Finally, a 120 kW AFPM motor is experimented with and the result matches well with the predicted data. The vibration performance of the AFPM motor with a dual rotor and sandwiched yokeless stator is revealed comprehensively.

This paper reports a method for calculating the electromagnetic force acting on an aluminum honeycomb sandwich panel moving in a magnetic field. This research is motivated by the non-contact electromagnetic detumbling technology for space non-cooperative targets. Past modeling of the electromagnetic forces and torques generally assumes that the target is homogeneous. However, aluminum honeycomb sandwich panels are extensively used in spacecraft structures to reduce weight without sacrificing structural strength and stiffness, which are so inhomogeneous and complicated that it is difficult to obtain the induced electromagnetic force even by numerical methods. An equivalent conductivity tensor of an aluminum honeycomb sandwich panel is proposed, which allows the aluminum honeycomb sandwich panel to be treated as a homogeneous structure when calculating the induced electromagnetic forces. The advantage of the equivalent conductivity tensor in the calculation of induced electromagnetic forces is verified by finite element simulations. The proposed method makes it possible to evaluate the electromagnetic force of a large aluminum honeycomb sandwich structure moving in a magnetic field. [ABSTRACT FROM AUTHOR]

In this paper, the influence of stator teeth deformation on electromagnetic force and acoustic noise of claw pole alternators was investigated. The characteristics of stator teeth deformation caused by welding and assembly were first illustrated, and the influence of stator teeth deformation on the frequency and spatial order of electromagnetic force harmonics was deduced analytically. Then the electromagnetic forces of three alternators with different stator teeth deformation types were simulated by the finite element method, and compared with the electromagnetic force of nominal alternator. In addition, a multi-physics simulation model was established and the electromagnetic noise of the above three different stator teeth deformation alternators was calculated. Finally, the changes in phase current and output current of claw pole alternator with and without stator teeth deformation were analyzed. The analysis results were verified by back-EMF bench test and noise bench test. Results showed that although stator teeth deformation would not change the frequency components of the electromagnetic force, but would generate additional electromagnetic force harmonics. When the number of deformed teeth was not an integer multiple of the rotor pole-pair number, the electromagnetic force harmonics with extra spatial order would appear. [ABSTRACT FROM AUTHOR]

Accurate calculation of the electromagnetic force distribution of transformer windings under different loads and fault conditions is of great significance for transformer maintenance, condition evaluation and life prediction. Due to the influence of offshore wind power systems, offshore wind power transformers have high harmonic content and large changes in load rates, which can easily cause the coil destabilization, winding deformation or even damage because of the uneven distribution of the electromagnetic force. To improve the accuracy of electromagnetic force calculation, this paper proposes a fractional order numerical method. First, a three-dimensional axisymmetric transformer model and a symmetrical lumped parameter equivalent circuit model are established, respectively, based on field-circuit coupling. Second, the fractional order approximation of circuit components is realized by using the improved Oustaloup filter. In the fractional order model, the transformer is replaced by the lumped parameter equivalent circuit model. Third, as in the calculation process for integer order electromagnetic force, the integer order current has a large error, and the current waveform does not match the actual power frequency. The fractional order current and electromagnetic force at the 0.9 order are closer to the rated value. Finally, the effects of different load rates, three-phase short circuits and harmonic conditions are studied with the fractional order model. Compared with the traditional integer order finite element electromagnetic model, the fractional order equivalent circuit model established in this paper is more accurate and suitable for electromagnetic force calculation. The proposed method is significant for the structural design and state detection of transformers and also could be applied in the analysis of other dry-type transformers. [ABSTRACT FROM AUTHOR]

Saving energy from domestic appliances is a focus in the effort to combat energy challenges. Linear compressors are a more efficient alternative to the traditional compressors used in refrigerators, which account for 20–40% of all residential electricity use. This article investigates the new topology of the moving magnet (MM), dual-stator single-mover linear oscillating actuator (DSSM-LOA) for linear compressor application. Both the stators were C-shaped, with coils looped across their end sides. Two permanent magnets (PMs) that were axially magnetized were housed on the mover. The PM structural shape significantly affected its fabrication cost and magnitude of magnetic flux density ( B ). The DSSM-LOA makes use of axially magnetized rectangular-shaped PMs because they are inexpensive and generate high electromagnetic (EM) force density. End ferromagnetic core materials were used to improve the magnetic flux, linking from the stator to the mover. All the design parameters were optimized through parametric analysis using the finite parametric sweep method. Parameters present within the three primary parameters (length, height, and depth) that were assumed constants were optimized, and the optimal dimensions were selected based on the EM force. The investigated DSSM-LOA was contrasted with traditional LOA designs, and they showed significant improvement in EM force per ampere, generally named motor constant (MC), MC per PM mass, MC density, cogging force, and stroke. Additionally, the proposed DSSM-LOA had a simple structure and low cost, and it operated in a feasible range of strokes for linear compressor application. [ABSTRACT FROM AUTHOR]

Asymmetry of the air gap in electrical machines impairs the output characteristics of both motors and generators. This asymmetry affects the magnetic induction at the poles and hence the pulsations of the electromotive force, current, and torque. The unidirectional attractive force of the rotor due to the asymmetry results in premature bearing failure and loss of the machine's reliability. The causes and consequences of the rotor's unidirectional attractive force are investigated, and analytical formulas are given for the asymmetry of the field and the magnetic attractive force. [ABSTRACT FROM AUTHOR]

The magnetic valve plays a key role in the air-flow weft insertion and injection system of the loom. In order to improve the weaving efficiency of the loom and solve the problem of solenoid valve response lag, an optimization method based on BP neural network prediction of electromagnetic force combined with multi-objective optimization genetic algorithm was proposed. Firstly, in view of the complex change of the magnetic resistance in the magnetic field caused by the change of the armature structure and position of the solenoid valve, which made it difficult to calculate the accurate electromagnetic force through the theoretical model, the BP neural network was used to predict the electromagnetic force of the solenoid valve. Secondly, NSGA-II was used to optimize the preserved BP neural network prediction model and the obtained mathematical model of the armature mass, and the Pareto frontier solution of the electromagnetic force and the armature mass of the solenoid valve was obtained; Finally, the optimal parameter combination was selected according to the standard closest to the original armature quality, and compared with the electromagnetic force of the original structure. The results show that the optimized electromagnetic force increases by 11.5%, but the armature mass decreases by 1%. The simulation experiment also verifies the effectiveness of the optimization method.

This article examines a new linear oscillating actuator (LOA) design that uses rectangular-shaped core materials and permanent magnets (PMs). The primary objective of the paper is to examine a novel LOA topology with a rectangular-shaped core and PMs as an alternative to the tubular LOA. A static core material is housed between the mover’s components and two stator cores with two coils, each of which is placed on either side of the mover. The dimensions of all the parameters are swept for optimization and the optimal parameter dimension is chosen based on the optimal value of the electromagnetic (EM) force. An analysis is done for output results like EM force and stroke. Parameters like input current, EM force and stroke-to-current ratio are investigated for different frequencies of the input electrical loading to demonstrate the significance of resonance operation. EM force per PM mass of the investigated design of LOA is 67 percent higher than that of a conventional rectangular-shaped LOA. Additionally, the EM force density of the proposed design is 23.8 percent higher than that of the conventional design of LOA. Furthermore, the stroke of the proposed LOA is also feasible and more than most of the designs of the LOA. Additionally, the proposed design of the LOA is simple in structure, low-cost, and feasible for fabrication.

Power transformer, as a crucial equipment for power transmission, frequently suffers winding deformation defects, owing to the impact of huge external short-circuit current in actual operation. To resist the rapid deterioration of the defects, online monitoring for winding states is imperative, depending on a thorough understanding of the deformation defects. Unfortunately, there are not much related research on the deformation form and location, as two key objects online diagnosed. In this paper, we concentrate on the analysis of winding deformation and investigation of its high-probability location to deeply understand the winding deformation. For the form of the deformation, a three-dimensional finite element model of the transformer is established to obtain the form and extent of the short-circuit impact force, and a buckling model of the low-voltage winding is designed to analyze the mechanism and form of winding deformation under the impact of huge force induced by short-circuit current. For the location of the deformation, the three-dimensional simulation models are established to analyze the force characteristics of different winding structures in three locations (the conductor transposition area, the area with imbalanced amp-turns and the area with uneven circumferential distribution of force). Then we clarify the possibility of winding deformation in these areas, defined as high-probability locations. Finally, the analyzed results are found to be highly consistent with the actual winding deformation, demonstrating the correctness of the research methods and conclusions. Next stage, the results will provide effective theoretical support for online diagnosis of winding deformation and optimal design of winding structure.

Electromagnetic resonance in electric motors arises when the electromagnetic force frequency coincides with any of the motor's natural frequencies, causing excessive vibration and noise. To address this issue, it is crucial to design motors such that their natural frequencies do not closely align with the electromagnetic force frequency. However, vacuum cleaner motors operate across a broad range of speeds, generating a multitude of electromagnetic force frequencies, which makes it challenging to establish natural frequencies that can avoid all possible electromagnetic resonances. This article presents a novel approach for shifting natural frequencies by adjusting the stiffness of stator cores. By integrating an auxiliary component with various design factors into the motor, a range of natural frequencies can be achieved. An optimal natural frequency that mitigates electromagnetic resonance was identified among these modified frequencies, and the subsequent enhancement in acoustic characteristics was demonstrated.

Audible noise radiated by electrical machines is gaining more and more importance in the design process of electrical machines. The radial electromagnetic forces in induction motors play an important role in the production of audible noise and vibrations. The magnetic flux pulsations at the iron surfaces produce these radial forces which act on the stator and rotor structures. A squirrel-cage induction motor produces electromagnetic vibration and noise caused by interaction between many harmonic fluxes in the air gap. In this paper, a new structure of the squirrel cage rotor to improve the distribution of the air gap magnetic flux and reduce the electromagnetic forces and, consequently, the electromagnetic noise in a single-phase induction motor will be introduced. For this purpose, in the proposed design the rotor bars are located on the rotor according to a sinusoidal form. The results show that this structure of the rotor improves the dynamic behavior and many parameters such as electromagnetic forces, harmonic distortion of magnetic flux, and torque ripple.

A new inhibition method was proposed for the problem of harmonic of radial electromagnetic force during the operation of the composite magnetic coupler. In order to suppress its radial electromagnetic force, a radial permanent magnet rotor eccentricity method is proposed, and a three‐dimensional finite element model is established. Based on the Maxwell tensor method, the radial electromagnetic force of the composite magnetic coupler is analysed, and the mathematical expression of its radial electromagnetic force is established, Maxwell stress tensor was used to analyse the radial electromagnetic force in a composite magnetic coupler and to establish the mathematical equation for the radial electromagnetic force. In order to suppress the radial electromagnetic force, a method based on rotor eccentricity in a radial permanent magnet was proposed. A prototype of a composite magnetic coupler with a rated power of 5 kW was designed to test its output torque under load. The results showed that the simulated curve was consistent with the tested curve, with a maximum numerical error of 8.9%. The tested values of the output torque before and after eccentricity were compared, and the results showed that the output torque remained basically unchanged after the eccentric structure was adopted and that the torque pulsation was significantly reduced. [ABSTRACT FROM AUTHOR]

Copyright of Zhejiang Electric Power is the property of Zhejiang Electric Power Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The conductor on round core (CORC) cables are fabricated with multilayer high-temperature superconductor tapes, which are helically wound around a circular central former. The large Lorentz force will be generated by the transport current in CORC cables under high magnetic field, which will affect the stress and strain distributions of tapes in the cables and the performance of superconducting tape. This paper establishes a two-dimensional axisymmetric model to analyze the mechanical response of CORC cables subjected to the Lorentz force and analyzes the influence of air gaps on stress and strain distributions inside the cables. The T-A method is used to calculate the distributions of current density, magnetic field and the Lorentz force in CORC cables. The mechanical response of CORC cables is analyzed by applying the Lorentz force as an external load in the mechanical model. The direction of electromagnetic force is analyzed in CORC cables with and without shielding current, and the results show that the shielding current can lead to the concentration of electromagnetic force. The maximum stress and strain occur on both sides of the superconducting tapes in the cables with shielding current. Reducing the size of air gaps can reduce the stress and strain in the superconducting layers. The analysis of mechanical response of CORC cables can play an important role in optimizing the design of CORC cables and improving transmission performance. [ABSTRACT FROM AUTHOR]

Electric arc melting of oxide materials under the influence of an external electromagnetic field is a high-current and high-temperature technological process, accompanied by powerful electric and magnetic fields and complex structural motion of the melt. In the general case, the movement of the melt in the bath of an electric arc installation is determined by a combination of thermocapillary, thermal concentration, thermal and electromagnetic convections. In this work, based on the analysis of convective flows and the calculation of the integral vortex field of Archimedes forces and electromagnetic forces in the bath, using the OKB-2126A ore-thermal furnace for melting oxide refractory materials as an example, an assessment of thermal and electromagnetic convections was carried out. For the first time it has been established that the value of the integral vorticity of the field of electromagnetic forces in the depth of the bath exceeds the integral vorticity of the field of Archimedes forces by 3-4 times. In real objects, this difference is even greater, since, compared to those accepted in the calculations, the actual current density in the bath is higher, and the temperature difference is lower. Thus, electromagnetic convection in ore-thermal furnaces for melting oxide materials significantly exceeds thermal convection and makes a decisive contribution to the formation of the structure and intensity of melt movement. [ABSTRACT FROM AUTHOR]

Copyright of Bearing is the property of Bearing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract A three-dimensional numerical model based on the volume-of-fluid (VOF) method is typically preferred for studying high-current gas metal arc welding (GMAW) metal transfer mechanism and then controlling it. It is informed that the rotating spray transfer is extremely complicated, and some researchers have focused on simplified models without considering the energy conservation to make analysis manageable for the unstable metal transfer process. Using our created numerical model, the metal transfer of high-current GMAW with shielding gas of different conductivities has been studied by analyzing acting forces and fluid flows in the metal liquid column, especially for the contributions of the self-induced electromagnetic force, equivalent volume force of the capillary pressure of the surface tension (Named surface tension force in this work), static arc pressure. It is found that the unbalanced electromagnetic force greatly promotes the metal rotating motion in 500 A metal inert gas (MIG) welding with pure argon shielding gas and it pushes the metal liquid column to rotate. Considering the arc constricting effect in active shielding gas by simply changing the arc conductivity, it is found that the metal liquid column no longer rotates, it turns to swing since the unbalanced electromagnetic force is large enough to break the rotating motion. The calculated results of the metal liquid column deflected angle and rotating/swing frequency agree well with the experiment of high-speed camera observations.

Abstract We propose a method to investigate the generation mechanism of the transient vibration of a pump motor induced by electromagnetic (electromagnetic (EM)) forces. Compared with the steady vibration of a pump motor, the transient vibration characterised by a wider excitation frequency spectrum and larger instantaneous amplitude makes the vulnerable structure more easily exposed to potential damage. However, transient vibration of pump motor has not been analysed and verified before. Based on the fact that EM vibration dominates the vibration of pump motors, in this study, an approach which integrates the field‐circuit coupling method and multi‐physics finite‐element (finite‐element (FE)) simulation is proposed to estimate the structural response of pump motors under transient operating conditions. To determine the factors that determine the EM forces, an analytical model describing the transient interaction between the EM and the fluid torque is first created. It was revealed that the input voltage and slip rate are two key factors that affect the transient EM forces. Then, to quantitatively describe the transient EM forces governed by a specific control scheme during the start‐up process, a field–circuit coupling model embedding in the control scheme, electrical circuit model, motor FE model, and rotor dynamic model is established. This model allows the circuit equations, rotor dynamics equations, and magnetic field equations to be solved simultaneously. The transient EM forces obtained by the field–circuit coupling model provide excitation for the structural response calculation. Subsequently, a multi‐physics FE simulation, which takes a weak coupling strategy between the EM and structural dynamics fields, is utilised to link the different physical domains. Thus, the EM forces are transferred to a structural domain to compute the structural response by adopting a direct integration method. The integration approach developed in this study was verified on the pump motors in the main cooling units of ultra‐high voltage (UHV) converter stations. The trends of dominant components of simulated signals agree with the measured signals from the pump motors. This indicates that the proposed method can be widely applied for the transient vibration analysis and mitigation for pump motors.

At geothermal power plants, there is a problem that hot spring water pipes are blocked by the "hot spring scale". The hot spring water used for geothermal power generation contains calcium, sulfur, and other substances, and the solid material called the "hot spring scale" adheres to the inside of steel pipes, significantly reducing the efficiency of steam transmission. In addition, there are maintenance costs to remove the "hot spring scale" inside the steel pipes. And it is important to evaluate the thickness of the hot spring scale inside the steel pipe. In this paper, a non-destructive sensor that is evaluated the thickness of the hot spring scale inside the steel tube from the outside of the steel pipe is proposed. The proposed sensor is consisted of a permanent magnet, an alternating excitation coil and an acceleration sensor. The static magnetic field from the permanent, and eddy current inside the steel pipe are generated the vibration in the steel pipe. And the thickness of the hot spring scale is evaluated from this vibration intensity. It is shown that the thickness of hot spring scale from 0 mm to 15 mm can be inspected by this proposed method. In addition, the proposed inspection principle of this inspection method will be clarified by 3-D electromagnetic force analysis and displacement analysis. [ABSTRACT FROM AUTHOR]

The magnetic valve plays a key role in the air-flow weft insertion and injection system of the loom. In order to improve the weaving efficiency of the loom and solve the problem of solenoid valve response lag, an optimization method based on BP neural network prediction of electromagnetic force combined with multi-objective optimization genetic algorithm was proposed. Firstly, in view of the complex change of the magnetic resistance in the magnetic field caused by the change of the armature structure and position of the solenoid valve, which made it difficult to calculate the accurate electromagnetic force through the theoretical model, the BP neural network was used to predict the electromagnetic force of the solenoid valve. Secondly, NSGA-II was used to optimize the preserved BP neural network prediction model and the obtained mathematical model of the armature mass, and the Pareto frontier solution of the electromagnetic force and the armature mass of the solenoid valve was obtained; Finally, the optimal parameter combination was selected according to the standard closest to the original armature quality, and compared with the electromagnetic force of the original structure. The results show that the optimized electromagnetic force increases by 11.5%, but the armature mass decreases by 1%. The simulation experiment also verifies the effectiveness of the optimization method. [ABSTRACT FROM AUTHOR]

The numerically simulated method of using electromagnetic field from an alternating current is a patented method to create in liquid metal, under the conditions of resonance, acoustic waves of sufficient strength to cause cavitation and implosion of gas bubbles, leading to beneficial degassing and grain refinement. The modelling stages of electromagnetics are described below along with acoustics in liquids, bubble dynamics, and their interactions. Sample results are presented for a cylindrical container with liquid aluminium surrounded by an induction coil. The possibility of establishing acoustic resonance and sustaining the bubble oscillation at a useful level is demonstrated. Limitations of the time-dependent approach to this multi-physics modelling problem are also discussed. [ABSTRACT FROM AUTHOR]

This study examines the distributions of the cogging and current forces in a hybrid linear motor and their impact on its performance. Subsequently, using the Maxwell stress tensor to analyze the force acting on the motor, a method has been proposed for calculating the cogging force effect on the mechanical system stiffness. Based on the force profile, it was found that the cogging force was a noncurrent force that could reduce the spring stiffness of a hybrid linear motor when it is in operation. An electromagnetic–mechanical coupling analysis was conducted to calculate the displacement and acceleration of the hybrid linear motor on a dummy jig. The experimental and analytical results were in good agreement, indicating that the proposed method is accurate and reliable. [ABSTRACT FROM AUTHOR]

There are different weft insertion methods used in the weaving machines. Electromagnetic launcher can be used as accelerator to yarn which is attached to the ferromagnetic projectile. For optimization of the projectile velocity in this new weft insertion, the projectile velocity should be obtained by numerous states of inputs (different states of launcher parameters). Experimental tests are very time consuming and costly. Therefore, a validated model (Adaptive Neuro Fuzzy Interface System: ANFIS) which can predict the system behavior accurately and faster than experiments was implemented to predict the projectile velocity. The optimization result of the genetic algorithm shows that achieving the modern weaving machines speed for this weft insertion system is possible by the optimal values of launcher parameters. Also, using the ANFIS model for obtaining the system output is very useful approach. So, the system can be optimized for other desired targets by this procedure. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of National University of Defense Technology / Guofang Keji Daxue Xuebao is the property of NUDT Press and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To improve the dynamic response speed of high-speed solenoid valves in electric fuel injection systems of marine diesel engines, a numerical simulation model of the solenoid valve is described in this paper. The accuracy of the simulation model was verified on the test bed of the solenoid valve. The effect of the punch position and the size of the dynamic response of the solenoid valve were investigated by using the distribution law of the electromagnetic force in the armature. The results of the test showed that armature drilling in the inter-yoke zone can optimize the solenoid closing response time, but it has little impact on the solenoid opening response time. From this rule, two groove schemes were further designed. Through comparison and calculation, it can be concluded that the fan groove scheme is better than the trapezoidal groove scheme, and that the opening and closing response times of the solenoid valve should be targeted in order to multi-target optimize the fan groove geometric parameters and the armature thickness. The results show that after optimization, the weight of the motion part is reduced by 21.6%, the opening response time of the solenoid valve is reduced by 11.1%, and the closing response time is reduced by 30.0%. While reducing the oil film damping of the armature motion, the overall dynamic response characteristics of the solenoid valve are improved. [ABSTRACT FROM AUTHOR]

Copyright of Electric Machines & Control / Dianji Yu Kongzhi Xuebao is the property of Electric Machines & Control and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

• The steady-state EMF is the body force and has self-regulating characteristic. • The maximum welding thickness of the plate is up to 30 mm in the steady-state EMF assisted laser welding in a single pass. • The intensity of the magnetic field and the density of the DC have the equivalent effect to control the magnitude of the steady-state EMF. Root collapse is the major problem in laser welding of the thick plate, limiting the maximum welding thickness in a single pass. The steady-state electromagnetic force (EMF), produced by direct current (DC) and rectangular magnets, greatly improve the welding stability at the root. Aiming to understand the influence of the EMF on the root collapse suppression, the transient simulation model of the EMF assisted laser welding is developed and deeply discusses the inner flow behaviors. The simulation results show the weld morphology has a great influence on the magnitude and orientation of magnetic field. The EMF is the body force and has self-regulating characteristic. The direction of the EMF is confirmed based on the Fleming's rule and mainly directed vertical. The experimental tests are implemented in full penetration laser welding of thick stainless steel. The EMF is the real working force on improving the welding stability, not the DC or magnetic field alone. The maximum thickness of the plate is up to 30 mm in a single pass. The intensity of the magnetic field and the density of the DC have the equivalent effect to control the magnitude of the EMF. The vector control of the EMF is more flexible. [ABSTRACT FROM AUTHOR]

The Magnetic Pulse Welding (MPW) process uses only electromagnetic force to create a solid-state metallurgical bond between a working coil and outer workpiece. The electromagnetic force drives the outer tube to collide with the inner rod, resulting in successful bonding. However, due to the dissimilarity of the MPW joint, only a portion of the interface forms a metallurgical bond, which affects the quality of the joint. Therefore, the purpose of this study is to analyze the effects of process parameters on joint quality through experimental work using RSM. Furthermore, an optimization algorithm is utilized to optimize the process parameters used in magnetic pulse welding. A1070 aluminum and S45C carbon steel were used as the materials, while peak current, gap between working coil and outer tube, and frequency were chosen as the process parameters for MPW. The welding conditions are determined through experimental design. After welding, the maximum load and weld length are measured to analyze the effect of the process parameters, and a prediction model is developed. Specifically, to achieve a high-quality joint, the process parameters are optimized using the Imperialist Competitive Algorithm (ICA) and Genetic Algorithm (GA). The results reveal that the peak current is a significant parameter, and the developed prediction model exhibits high accuracy. Furthermore, the ICA algorithm proves very effective in determining the process parameters for achieving a high-quality Al/Steel MPW joint.

Abstract The noise and vibration level in modular‐type permanent magnet synchronous machines with fractional slot concentrated windings (FSCW) is considered to be an important design consideration, particularly for applications requiring fault tolerance. In this work, an interior permanent magnet synchronous machine (IPMSM) with FSCW is designed in a modular manner by dividing its stator windings into different arrangements having independent three‐phase sub‐modules with separate neutral points. First, the modular concentrated winding arrangement is studied to investigate the radial forces, vibration, and the associated noise level in the prototype machine having three‐phase sub‐modules under open‐circuit fault conditions. Then, another type of distributed three‐phase sub‐module winding arrangement is analysed to further investigate the vibration and noise level in the same prototype machine under the same operating conditions. A detailed two‐dimensional (2D) fast Fourier transform analysis is performed to investigate and compare the machine radial forces, induced harmonics, and sub‐harmonics for the two analysed winding arrangements. Considering the advantages and disadvantages of both the winding arrangements, the third type of mixed concentrated and distributed three‐phase sub‐modules winding arrangement is introduced in this work, combining the first two winding design approaches. A comprehensive harmonic (3D) structure, along with the vibration and noise analysis, is performed using a multi‐physics model analysis for all the winding arrangements under different three‐phase sub‐modules open‐circuit fault conditions. Lastly, the vibration levels of all the machine prototype models under different winding arrangements are experimentally validated. Moreover, the different modular types of winding arrangements are deeply investigated in this work to suggest the best winding arrangement approach that enables the machine to work in a wide range of applications requiring lower power levels or under critical, faulty, and hostile conditions. The proposed winding arrangement has reduced stator deformation with a reduced vibration and noise level under three‐phase sub‐modules open‐circuit fault‐tolerant conditions that can be used according to process requirements.

In this article, we propose a new regression equation to predict the noise of a power transformer based on the winding vibration under a loading condition. A regression between load noises and tank vibrations for multiple transformers with different rated powers was confirmed through measurements and regression analysis. A regression equation for load noise and winding vibration was derived considering the fact that the winding vibration level is proportional to the tank vibration level. The electromagnetic force, which is the excitation force of the winding, was obtained using the equivalent magnetic circuit network method to obtain the winding vibration required for the regression equation. Subsequently, the obtained force was applied to a finite element model for the winding to achieve the vibration response. The winding vibration obtained through these methods is closely correlated with the load noise, and the amount of winding vibration transferred to the tank could be changed according to the distance between the tank and the winding. Accordingly, an equation for predicting the load noise was established considering the winding vibration and the correlation factors according to the distance of the transmission path. The proposed prediction equation is considerably more accurate than the previous prediction equation. [ABSTRACT FROM AUTHOR]

The NVH (noise, vibration, harshness) performance of a motor is one of the main problems affecting the comfort, safety, and reliability of electric vehicles. Electromagnetic force is the main cause of motor noise. Most of the existing research focuses on the overall noise level, and does not consider the impact of specific orders of electromagnetic force on noise, which results in a lack of applicability of noise reduction techniques. In this paper, a rotor with an auxiliary slot was used to weaken the electromagnetic force. A multi-objective optimization algorithm combining finite-element simulation with a response surface method was proposed. To determine the relationship between specific orders of electromagnetic force and the auxiliary slot parameters, simulation experiments were carried out with a large range and a large step size in finite-element analysis software. Then, the parameter range with a low value of electromagnetic force was selected. In this new range, the response surface method was used to establish the parameter and electromagnetic force expressions. Then, the linear weighting method in the multi-objective optimization algorithm was selected to determine the objective function of the multi-order electromagnetic force optimization. The weight of each order of electromagnetic force was set according to its contribution to the noise. Finally, the effectiveness of the proposed method was verified by simulations. Simulation results show that this method can quickly and effectively determine the optimal size of the auxiliary slot. In addition, the maximum value of the noise was reduced from 107.6 to 103.2 dB. [ABSTRACT FROM AUTHOR]