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Author Topic: Software Simulation of Magnetic Viscosity  (Read 9027 times)

gravityblock

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Software Simulation of Magnetic Viscosity
« on: March 08, 2010, 06:00:36 AM »
According to Sean McCarthy in 2007, they use an FEA package called Flux3D from Cedrat ( http://www.cedrat.com ). Sean says, "I should point out that the system does require some code changes in order to demonstrate the effect which is based around Magnetic Viscosity", http://peswiki.com/index.php/Steorn#Software_Modeling

The purpose of this thread is to use Flux3D or other simulation software in order to simulate the effect of magnetic viscosity with the main focus on the needed code changes to demonstrate this effect.  After we know what the needed code changes are, then we can have a discussion on the simulation results.

Flux3D, http://www.cedrat.com/en/software-solutions/flux.html

Flux is suitable for designing, analyzing and optimizing a variety of devices and applications such as :  Rotating machines, Linear actuators, Electromagnetic compatibility, Transformers, Induction heating devices, Sensors - HV devices, Cables, Nondestructive Evaluation

I think this would be an exciting project.

GB

gravityblock

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Re: Software Simulation of Magnetic Viscosity
« Reply #1 on: March 08, 2010, 06:41:33 AM »
Flux 3D is a finite element software (FEA) application and isn't open sourced, so it may not be the best choice in order to have the greatest amount of participation with this project.  There is however, alot of good documents on Cedrat. 

FEMM, http://www.femm.info/wiki/HomePage is also an FEA software, is open-sourced, and is well known to most users here.  FEMM may be a good choice, but I would like to know if it's the best choice for this purpose by reviewing the list of simulation software on wiki.  Here is a list of Finite Element Software packages found on wiki, http://en.wikipedia.org/wiki/List_of_finite_element_software_packages

Thanks,

GB

gmeast

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Re: Software Simulation of Magnetic Viscosity
« Reply #2 on: March 08, 2010, 06:30:57 PM »
Flux 3D is a finite element software (FEA) application and isn't open sourced, so it may not be the best choice in order to have the greatest amount of participation with this project.  There is however, alot of good documents on Cedrat. 

FEMM, http://www.femm.info/wiki/HomePage is also an FEA software, is open-sourced, and is well known to most users here.  FEMM may be a good ---
----------------------------
Thanks,

GB

@ thread,

Magnetic viscosity has been observed and characterized countless times.

Changing simulation software can end up being a monumental task and may only serve to raise suspicion
as to motive ... not from me, but why give anyone the ammunition?

How about a table tabulated from data points acquired from a test rig built to specifically characterize magnetic viscosity in an Orbo motor configuration?  Then you use that data to "correct" the results of the simulation.

I personally don't like doing this since this is what the climate folks recently did that resulted in "ClimateGate".  Their "correction" was actually a 'biasing' of the data to keep their grants rolling in.

Quoting and crediting the following from the link:
http://prola.aps.org/abstract/PR/v54/i4/p288_1
(Look at the date.  I'm sure there are earlier references)

My 2 cents,

Greg
-----------------------------------------------------
C. W. Heaps
The Rice Institute, Houston, Texas

Received 20 June 1938

Magnetic viscosity—the change of induction occurring after the magnetizing field has ceased to vary—has been measured in a bar of commercial iron, with a measuring circuit designed to eliminate spurious effects arising from sparking at switches. Magnetic viscosity is found to depend on previous magnetic states, in agreement with observations of Mitkevitch and contrary to Preisach's results. It appears, therefore, as if reversible domains could retain their lagging propensity while the magnetic force is varying over a considerable range. The viscous effect is found to depend on the magnitude of the previous change of induction if the latter is small, but is independent of this change if it is greater than 60 gauss. In small, subsidiary hysteresis loops, such as are used in determining reversible permeability, it is found that the Barkhausen effect is not present although there is hysteresis and magnetic viscosity. It is therefore concluded that the movement of the boundaries of saturated domains in the material is subject to time-lag.

© 1938 The American Physical Society
-----------------------------------------------------

gravityblock

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Re: Software Simulation of Magnetic Viscosity
« Reply #3 on: March 08, 2010, 08:47:14 PM »
@ thread,

Changing simulation software can end up being a monumental task and may only serve to raise suspicion
as to motive ... not from me, but why give anyone the ammunition?

How about a table tabulated from data points acquired from a test rig built to specifically characterize magnetic viscosity in an Orbo motor configuration?  Then you use that data to "correct" the results of the simulation.

I personally don't like doing this since this is what the climate folks recently did that resulted in "ClimateGate".  Their "correction" was actually a 'biasing' of the data to keep their grants rolling in.

Quoting and crediting the following from the link:
http://prola.aps.org/abstract/PR/v54/i4/p288_1
(Look at the date.  I'm sure there are earlier references)

My 2 cents,

Greg
-----------------------------------------------------
C. W. Heaps
The Rice Institute, Houston, Texas

Thanks for your input and your concerns are valid.  If FEMM could simulate the magnetic viscosity, then it would help us to determine the best core materials and properties.  From the little research I have done so far, I don't think it's much more than a few equations based around the B-H hysteresis loop.  Here's an article on computer software simulation of magnetic viscosity with a few equations, http://www.overunity.com/index.php?action=downloads;sa=downfile&id=376

If FEMM isn't programmed to take this effect into account, then I don't see anything wrong with making a few code changes in order to simulate an effect.  This is probably more common than you think. This is what Steorn has done with Flux3D and probably for a good reason.

I think a table tabulated from data points acquired from a test rig built to specifically characterize magnetic viscosity in an Orbo motor configuration is a good idea also.  I have an article from the late 1800's on magnetic viscosity by E. Rutherford, http://www.overunity.com/index.php?action=downloads;sa=downfile&id=375  This research was undertaken to see if steel or soft iron exhibited any appreciable magnetic viscosity when under the influence of very rapidly changing fields.  It describes a special form of apparatus for measuring short intervals.  It also says soft iron and steel exhibit the effect of magnetic viscosity quite strongly for a frequency of 1,000 (This could be very important).

GB
« Last Edit: March 08, 2010, 09:36:35 PM by gravityblock »

ken_nyus

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Re: Software Simulation of Magnetic Viscosity
« Reply #4 on: March 09, 2010, 01:09:35 AM »

gravityblock

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Re: Software Simulation of Magnetic Viscosity
« Reply #5 on: March 09, 2010, 04:38:39 AM »
Have you guys seen the Steorn patent for a test rig?

http://www.google.com/patents?id=1dOyAAAAEBAJ&zoom=4&pg=PA1#v=onepage&q=&f=true

Yes, I have a thread for that patent, http://www.overunity.com/index.php?topic=8763.0

The thread died very quickly and it won't surprise me if this thread dies a quick death also.

GB

gravityblock

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Re: Software Simulation of Magnetic Viscosity
« Reply #6 on: March 11, 2010, 01:51:21 AM »
I found an abstract for an article which I believe will allow us to simulate the magnetic viscosity effect by optimum simulation of B-H curves in FEM analysis of magnetic fields, http://library.witpress.com/pages/PaperInfo.asp?PaperID=9161

The paper introduces a new algorithm for the numerical simulation of magnetisation curves, suitable for Newton iterative process in FEM analysis of non-linear magnetic fields, both for dc magnetisation curves and for hysteresis loops.

The algorithm, from the complete data sheet of the magnetic material, determines the number and the location of the points which set is minimum and ensures a global error lower that a control quantity.

Introduction in FEM analysis of static electromagnetic fields where non-linear materials are present, it is necessary to determine numerically the magnetic field H from the knowledge of the magnetic flux density B as well as dH(B)/dB.

The same problem holds for dynamic simulations, where the hysteresis of the material has to be taken into a...

Electrical engineers know the magnetic viscosity effect as either "anomalous loss," "excess loss," or "dynamic hysteresis".

If this is the case, then the necessary code changes shouldn't cause any suspicion as to motives from others.  The code changes would allow to simulate a dynamic hysteresis instead of a static hysteresis.  This optimized code may even take demagnetization from heat into account and allow us to have a visual if there is any cooling effects in the materials. The only problem is the cost for the article.  The complete book is even more.

If anyone could find this paper or another similar paper and post it here, I would greatly appreciate it.  I will continue searching.

Thanks,

GB
« Last Edit: March 11, 2010, 04:11:53 AM by gravityblock »

synchro1

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Re: Software Simulation of Magnetic Viscosity
« Reply #7 on: March 12, 2010, 08:23:16 PM »
JLN has offered to release a new S2Gen calorimetric test video soon. Preliminary tests of his 2SGen V6 so far indicate a joule heat loss from the inductor to cooling from the toroid that results in an ambient balance of toroid temperature. His forthcoming testing will help supply parameters to advance a simulation. I bet he'll be interested in cooperating with this software project.

gravityblock

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Re: Software Simulation of Magnetic Viscosity
« Reply #8 on: March 13, 2010, 11:14:07 PM »
JLN has offered to release a new S2Gen calorimetric test video soon. Preliminary tests of his 2SGen V6 so far indicate a joule heat loss from the inductor to cooling from the toroid that results in an ambient balance of toroid temperature. His forthcoming testing will help supply parameters to advance a simulation. I bet he'll be interested in cooperating with this software project.

That would be great, Thanks Synchro.

GB

gravityblock

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Re: Software Simulation of Magnetic Viscosity
« Reply #9 on: April 02, 2010, 03:53:48 AM »
Finite element simulations of the eOrbo implementation provided by Steorn, confirms the lack of back EMF and the increase in kinetic energy of the system's rotor. The simulations are run in Flux3D from Cedrat.  These tests may be simulating the effects of magnetic viscosity and is similar to the real tests performed on The Patented Magnetic Torque Measurement System.  Why aren't we running any simulations, or trying to figure out how to run these simulations, or building a torque measurement system?

http://www.steorn.com/orbo/eorbo/3-finite-element-simulations.aspx

GB