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AC/DC - Circular Permanent Magnet
Posted May 31, 2012, 1:39 p.m. EDT Low-Frequency Electromagnetics, Studies & Solvers 2 Replies
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Hello,
I am building a 3D model using COMSOL 4.2. In this model I want to simulate a rotating disk in a magnetic field. The induced Lorentz's force will slow the disk. For that, my model consists on an iron core with a circular shape (the magnet) and a Copper disk. My problem is how to design the circuar magnet in COMSOL. You can find attached the images of the geometry (the rotating disk is on red, the iron core on blue).
Thanks for answering.
Best Regards .
John J
I am building a 3D model using COMSOL 4.2. In this model I want to simulate a rotating disk in a magnetic field. The induced Lorentz's force will slow the disk. For that, my model consists on an iron core with a circular shape (the magnet) and a Copper disk. My problem is how to design the circuar magnet in COMSOL. You can find attached the images of the geometry (the rotating disk is on red, the iron core on blue).
Thanks for answering.
Best Regards .
John J
2 Replies Last Post May 31, 2012, 7:42 p.m. EDT
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Posted:
1 decade ago
Hi
so the magnet is the external red cylinder ? and the rotating red internal smaller disk is floating between the two iron cores ?
If so, well you have the geometry then yo uneed to define the materials and the magnetisation (with such a cylindrical symmetry its worth to define a cylindrical coordinate.
If you want to use the rotary RMM physics, you still need to "box" or enclose with a cylinder the middle of the air gap between the rotating and the fixed parts, nd use assembly mode to enable the true rotation of one physics w.r.t. the other. if not there is the "physics of rotating the reference frame method.
Have you checked the model library eddy current brake ?
--
Good luck
Ivar
so the magnet is the external red cylinder ? and the rotating red internal smaller disk is floating between the two iron cores ?
If so, well you have the geometry then yo uneed to define the materials and the magnetisation (with such a cylindrical symmetry its worth to define a cylindrical coordinate.
If you want to use the rotary RMM physics, you still need to "box" or enclose with a cylinder the middle of the air gap between the rotating and the fixed parts, nd use assembly mode to enable the true rotation of one physics w.r.t. the other. if not there is the "physics of rotating the reference frame method.
Have you checked the model library eddy current brake ?
--
Good luck
Ivar
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Posted:
1 decade ago
Hi Ivar,
Thank you for your response.
In fact it is a similar model to the one in the model gallery: www.comsol.com/showroom/gallery/2014/
The only difference is that iron cores have a circular shape as show in the attached images. I will give you all the details of the model:
the rotating disk(Copper) has a radius dr = 10[cm] and thichkness dt = 1[cm]
1. Firstly I defined a sphere with radius 3*dr in order to define the air space
2. Then, I defined the rotating disk (the red internal smaller disk)
3. I defined the two cylindrical irons
4. I defined the Magnet(the red external cylinder) and I selected Remanent flux density in Ampère's Law and Current Conservation: Br = (0 0 mB) mB = 1[T].
So my model is almost the same model of the one in the gallery just I have changed the the shape of the part of the disk where I want to apply the permanent magnetic field in order to make the problem axisymmetric: In the model gallery the magnetic filed Br is applied in a square part of the disc and in my model Br is applied in a circular part of the disk and this why I have changed the geometry of iron cores. Unfortunately I get the error: Last time step is not converged.
N.B: I am not using RMM physics because the Br(applied permanant magnet is static).
Thank you again for your help Ivar.
Best regards.
John J
Thank you for your response.
In fact it is a similar model to the one in the model gallery: www.comsol.com/showroom/gallery/2014/
The only difference is that iron cores have a circular shape as show in the attached images. I will give you all the details of the model:
the rotating disk(Copper) has a radius dr = 10[cm] and thichkness dt = 1[cm]
1. Firstly I defined a sphere with radius 3*dr in order to define the air space
2. Then, I defined the rotating disk (the red internal smaller disk)
3. I defined the two cylindrical irons
4. I defined the Magnet(the red external cylinder) and I selected Remanent flux density in Ampère's Law and Current Conservation: Br = (0 0 mB) mB = 1[T].
So my model is almost the same model of the one in the gallery just I have changed the the shape of the part of the disk where I want to apply the permanent magnetic field in order to make the problem axisymmetric: In the model gallery the magnetic filed Br is applied in a square part of the disc and in my model Br is applied in a circular part of the disk and this why I have changed the geometry of iron cores. Unfortunately I get the error: Last time step is not converged.
N.B: I am not using RMM physics because the Br(applied permanant magnet is static).
Thank you again for your help Ivar.
Best regards.
John J