scholarly journals Numerical 3D Simulation of a Full System Air Core Compulsator-Electromagnetic Rail Launcher

2020 ◽  
Vol 10 (17) ◽  
pp. 5903 ◽  
Author(s):  
Valentina Consolo ◽  
Antonino Musolino ◽  
Rocco Rizzo ◽  
Luca Sani
Keyword(s):  
Eddy Currents ◽  
Mechanical Response ◽  
Response Times ◽  
Electric Circuit ◽  
Coupled Analysis ◽  
3D Analysis ◽  
Electromagnetic Modeling ◽  
Electrical Equivalent Circuit ◽  
Electromagnetic Launchers ◽  
Air Core

Multiphysics problems represent an open issue in numerical modeling. Electromagnetic launchers represent typical examples that require a strongly coupled magnetoquasistatic and mechanical approach. This is mainly due to the high velocities which make comparable the electrical and the mechanical response times. The analysis of interacting devices (e.g., a rail launcher and its feeding generator) adds further complexity, since in this context the substitution of one device with an electric circuit does not guarantee the accuracy of the analysis. A simultaneous full 3D electromechanical analysis of the interacting devices is often required. In this paper a numerical 3D analysis of a full launch system, composed by an air-core compulsator which feeds an electromagnetic rail launcher, is presented. The analysis has been performed by using a dedicated, in-house developed research code, named “EN4EM” (Equivalent Network for Electromagnetic Modeling). This code is able to take into account all the relevant electromechanical quantities and phenomena (i.e., eddy currents, velocity skin effect, sliding contacts) in both the devices. A weakly coupled analysis, based on the use of a zero-dimensional model of the launcher (i.e., a single loop electrical equivalent circuit), has been also performed. Its results, compared with those by the simultaneous 3D analysis of interacting devices, show an over-estimate of about 10–15% of the muzzle speed of the armature.

scholarly journals Thermal Analysis of Air-Core Power Reactors

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Zhao Yuan ◽  
Jun-jia He ◽  
Yuan Pan ◽  
Xiao-gen Yin ◽  
Can Ding ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Heat Transfer Process ◽  
Coupled Analysis ◽  
Test Results ◽  
Thermal Test ◽  
Air Core ◽  
Structural Details ◽  
Simulation Results ◽  
Heat Conduction Process

A fluid-thermal coupled analysis based on FEM is conducted. The inner structure of the coils is built with consideration of both the structural details and the simplicity; thus, the detailed heat conduction process is coupled with the computational fluid dynamics in the thermal computation of air-core reactors. According to the simulation results, 2D temperature distribution results are given and proved by the thermal test results of a prototype. Then the temperature results are used to calculate the heat flux to predict the detailed heat transfer process in the packages of the reactors. The study in this paper may be useful in the design optimization in air-core reactors.

Assessment of d.c. traction stray currents effects on nearby pipelines

2016 ◽  
Vol 35 (4) ◽  
pp. 1468-1477 ◽  
Author(s):  
Wojciech Machczynski ◽  
Krzysztof Budnik ◽  
Jan Szymenderski
Keyword(s):  
Simulation Model ◽  
Electric Circuit ◽  
Voltage Source ◽  
Electrode Kinetics ◽  
Polarization Phenomenon ◽  
Electrical Equivalent Circuit ◽  
Content Type ◽  
Method Of Calculation ◽  
Non Linear ◽  
Lumped Parameters

Purpose – dc electrified traction systems are a potential source of stray currents. The purpose of this paper is to evaluate the harmful effects (electrolytic corrosion) that an electrified railway has on nearby earth return circuits (e.g. pipelines). Design/methodology/approach – The electric circuit approach, based on the earth return circuit theory, to model stray currents interference on extended structures is presented. An exact method of calculation is applicable to any dc railway system in which tracks can be represented by a single earth-return circuit (equivalent rail) with current energization. In the approximate method, the equivalent rail with current energization is modeled as a large multinode electrical equivalent circuit with lumped parameters. The circuit is a chain of basic circuits, which are equivalents of homogenous sections of the rail. The electrode kinetics (polarization phenomenon) is taken into account in the model developed. Findings – Formulas in partially closed forms are derived applicable to the analysis of currents and potentials along a pipeline laid in the proximity with railway tracks. The attempt is undertaken, to incorporate the electrode kinetics into the simulation model in which the polarization phenomenon (Tafel equation) is modeled by a non-linear voltage source with source voltage being iteratively calculated. The polarization potential along the affected pipeline can be determined. Originality/value – The pipeline electrochemical response (polarization behavior – non-linear phenomenon on the interface metal-soil electrolyte) to the dc stray currents interference is innovative incorporated into the simulation model with lumped parameters using the iterative process.

scholarly journals Reluctance network lumped mechanical & thermal models for the modeling and predesign of concentrated flux synchronous machine

Open Physics ◽  
2018 ◽  
Vol 16 (1) ◽  
pp. 692-705 ◽  
Author(s):  
Mohammed Ali Benhamida ◽  
Hamza Ennassiri ◽  
Yacine Amara
Keyword(s):  
Soft Magnetic Materials ◽  
Coupled Analysis ◽  
Electrical Machine ◽  
Permanent Magnet Machines ◽  
Electromagnetic Modeling ◽  
Mechanical Modeling ◽  
Soft Magnetic ◽  
Thermal Models ◽  
Electrical Vehicles ◽  
Reluctance Network

Abstract The aim of this paper is the multi-physical modeling of synchronous permanent magnet machines, dedicated to hybrid electrical vehicles application, using reluctance network lumped mechanical and thermal models. The modeling approaches are presented and validated by comparing the obtained results to those of finite element method with a close look to the airgap modeling and the consideration of soft magnetic materials non-linearity in the electromagnetic modeling. As well as a close look also on the conduction and convection heat coefficients for the machine different regions in the thermal modeling. Finally a focus on the mass, damping and stiffness matrix computation in lumped mechanical modeling taking into account the temperature influence on the materials mechanical properties. In addition a simplified rotating electrical machine is described and multiple coupled analysis were done in order to derive the structure magneto-vibroacoustic performances.

The Impact of Peak-and-Hold and Reverse Current Driving Strategies on the Dynamic Performance of Commercial Cartridge Valves

2014 ◽  
Author(s):  
Farid Breidi ◽  
Tyler Helmus ◽  
Michael Holland ◽  
John Lumkes
Keyword(s):  
Power Systems ◽  
Input Signal ◽  
High Speed ◽  
Energy Savings ◽  
Eddy Currents ◽  
Response Times ◽  
Dynamic Performance ◽  
Reverse Current ◽  
Hydraulic Systems ◽  
The Impact

High speed valves have an important role in many existing fluid power systems and are an enabler for many proposed digital hydraulic systems. One method commonly used to improve the dynamic performance of on-off valves involves modifying the electrical input signal to the solenoids to reduce the inductive lag and eddy current decay. This research examined two commercially available direct actuated and pilot-stage actuated cartridge poppet valves and the role of peak-and-hold voltage and reverse current input profiles on opening and closing switching times. A test stand was built to characterize the performance of these valves. The valves were placed between two high frequency pressure transducers and the pressure differential across the valves was recorded, allowing the calculation of transition and delay time. The peak and reverse voltage duration was tested over a range of zero to ten milliseconds and an optimum response was found at a peak duration of six to eight milliseconds. Peak voltages ranged from 50 to 55 volts, followed by a holding voltage of 12 volts. Reverse current profiles were used to turn off the valves with a maximum peak current of three amps. The reverse current was used to increase the decay rate of eddy currents thus improving the turning off performance of the valves. Commercial valves that had a range of 33 to 55 millisecond turn-on response without input signal modification; these same valves had response times reduced to a range of seven to nine milliseconds after applying the peak and hold method. The turn-off time was reduced from 130 milliseconds to a range of 16 to 50 milliseconds after adding reverse current inputs. This improvement in valve performance can lead to siginificant energy savings due to reduction of transition losses and can widen the useful application of the valves.

Neural and Mechanical Response Time for Speech Production

1974 ◽  
Vol 17 (4) ◽  
pp. 608-618 ◽  
Author(s):  
Ronald Netsell ◽  
Billie Daniel
Keyword(s):  
Reaction Time ◽  
Response Time ◽  
Speech Production ◽  
Mechanical Response ◽  
Response Times ◽  
Production Task ◽  
Dysarthric Speech ◽  
Intraoral Air Pressure ◽  
Neurologically Normal ◽  
Response Group

The reaction time of 10 neurologically normal young adults was determined for a speech production task. The response was production of a CVC word following the offset of an auditory stimulus tone. Electromyography (EMG) was used to mark the onset of orbicularis oris activity in the response, and the interval between stimulus and EMG onset was designated as neural time. Mechanical response time was measured as the interval between EMG onset and the rise in intraoral air pressure marking the completion of the movement in the response. Group neural times and mechanical response times were approximately 140 and 60 msec, respectively, yielding a 200-msec reaction time. The usefulness of the reaction time paradigm is discussed in relation to studies of sensorimotor control in normal and dysarthric speech.

scholarly journals ELECTRODYNAMIC BRAKING IN HIGH‐SPEED RAIL TRANSPORT

Transport ◽  
2007 ◽  
Vol 22 (3) ◽  
pp. 178-186 ◽  
Author(s):  
Lionginas Liudvinavičius ◽  
Leonas Povilas Lingaitis
Keyword(s):  
High Speed ◽  
Eddy Currents ◽  
Electric Circuit ◽  
Railway Transport ◽  
High Speed Rail ◽  
Linear Motors ◽  
High Speed Trains ◽  
Braking Force ◽  
Electric Braking ◽  
Contact Free

The paper considers electrodynamic braking of trains, which is of particular importance for high‐speed railway transport from theoretical and technical perspectives. Braking methods used for high‐speed trains should ensure compatibility and redundancy of braking systems. They include a mechanical method (based on adding frictional disks to wheelsets), as well as magnetic braking, which is being currently implemented and based on eddy currents, etc. High‐speed trains have AC/DC engines, for which the principles of electric braking can be applied. Electrodynamic braking is of particular importance for high‐speed transport using linear motors and developing the speed of 400–500 km/h. These traction rolling stocks will not have commonly used trucks. The tests in this area are being conducted in Japan and Germany now. The paper suggests some theoretical and practical solutions to these problems. Schematic diagrams of the locomotive braking and ways of controlling the braking force by varying electric circuit parameters are presented. The authors suggested contact‐free regulation of braking rheostat resistor for controlling braking force in rheostatic braking. A schematic diagram of harmonizing electrified railways and power system's upgrading aimed at ensuring power regeneration is also presented.

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