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modeling a rotating electrical machine

Posted Feb 10, 2011, 4:36 p.m. EST Low-Frequency Electromagnetics Version 4.3b 12 Replies

Arda Tüysüz
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Dear Comsol Users,

I am trying to model a simple rotating machine in Comsol 4.0a. I am attaching the model file.

Unfortunately, I couldn’t find any documentation or examples how to start up a model using the “Rotating Machinery, Magnetic (rmm)” physics interface, where a time dependent solution is done. Do you have any similar models available as an example for me?

It is hard to formulate my questions, as I basically cannot get the model to work properly. For example, the field lines I get in the airgap don’t seem to be continuous.

I tried opening the 2D generator example for v3.5 in v4.0 and tried to trace the steps back but it didn’t help as in v4 it didn’t make use of the physics interface I wanted.

I would be very happy if you could take a look in my (very simple) model and tell me

- how to define that rotating permanent magnet properly,
- how to model the rotation, moving mesh, airgap (continuity) boundary conditions
- how to post process in order to see the field lines for different time steps

I am sorry for formulating this in such a poor way, but I tried many different things and got confused over the settings, and I thought instead of going through what I did step by step, I should just ask for the better way of doing it on this really simple model. I hope someone could help me.

Best regards,
Arda




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12 Replies Last Post Jan 16, 2014, 5:02 a.m. EST
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Feb 11, 2011, 1:34 a.m. EST
Hi

not all the features used for rotary machines were ironed out in 4.0, you should upgrade to the latest version, it would run far smoother and better !

--
Good luck
Ivar
Hi not all the features used for rotary machines were ironed out in 4.0, you should upgrade to the latest version, it would run far smoother and better ! -- Good luck Ivar
Arda Tüysüz
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Posted: 1 decade ago Feb 11, 2011, 6:10 a.m. EST
Hi,

Thanks for the answer. I took the advise and tried it in v4.1.

I opened the model example of rotating generator (2D) for v3.5 in v4.1 and changed the physics a bit.

If you open the attached file, in the post processing window it is clear that there is something wrong, as the non-moving part is not updated as I try to look at the solutions of different time steps. I tried with the different x,y,z, or X,Y,Z frames but couldn't find the right-looking combination. Furthermore, the axial torque and the z-torque are not the same, which I wasn't expecting. Therefore I am not sure if I am having a post processing problem or if the model itself is wrong.

I would be very happy if you could take a look into the model. Thanks in advance!

Arda

Hi, Thanks for the answer. I took the advise and tried it in v4.1. I opened the model example of rotating generator (2D) for v3.5 in v4.1 and changed the physics a bit. If you open the attached file, in the post processing window it is clear that there is something wrong, as the non-moving part is not updated as I try to look at the solutions of different time steps. I tried with the different x,y,z, or X,Y,Z frames but couldn't find the right-looking combination. Furthermore, the axial torque and the z-torque are not the same, which I wasn't expecting. Therefore I am not sure if I am having a post processing problem or if the model itself is wrong. I would be very happy if you could take a look into the model. Thanks in advance! Arda

Attachments:

Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Feb 11, 2011, 9:29 a.m. EST
Hi

there is also a rotary generator in v4.1, check the "Options - model library update" to get the latest models downloaded

--
Good luck
Ivar
Hi there is also a rotary generator in v4.1, check the "Options - model library update" to get the latest models downloaded -- Good luck Ivar
Arda Tüysüz
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Posted: 1 decade ago Feb 11, 2011, 10:06 a.m. EST
Hi Ivar,

Thanks for the quick reply. I just checked but could not see the rotary transformer model for v4.1. Are you sure it's not the static 3D generator example you mentioned?

Best,
Arda
Hi Ivar, Thanks for the quick reply. I just checked but could not see the rotary transformer model for v4.1. Are you sure it's not the static 3D generator example you mentioned? Best, Arda
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Feb 11, 2011, 3:22 p.m. EST
Hi

you are right that the model library example is a 3D withou any rotation part.

But for me your model seems OK (apart that there is no current in the coils=air so OK you are probably in generator mode, but more important: you are in geoemtry "union" mode so the rotating part is "fixed"

you must group (composed geometry but that is already done) all but the central ring and then use "assembly" mode + add a continuity/identity pair for boundaries

{32, 33, 63, 64} with {121, 122, 138, 139]

+ add the "continuity pair" in the physics

you should also use L=0.4[m forthe physics length (Z direction) I believe or you have foreseen to calculate per 1[m] and normalise with L ?

and your internal variables should use "rmm.Ez" and not the 3.5a name emqa.Ez

finally use a finer time step to better resolve the oscillations with 1 turn/sec and 8 poles you have 4 sinus per turn

With that I see a 4V amplitude sinus out

--
Good luck
Ivar
Hi you are right that the model library example is a 3D withou any rotation part. But for me your model seems OK (apart that there is no current in the coils=air so OK you are probably in generator mode, but more important: you are in geoemtry "union" mode so the rotating part is "fixed" you must group (composed geometry but that is already done) all but the central ring and then use "assembly" mode + add a continuity/identity pair for boundaries {32, 33, 63, 64} with {121, 122, 138, 139] + add the "continuity pair" in the physics you should also use L=0.4[m forthe physics length (Z direction) I believe or you have foreseen to calculate per 1[m] and normalise with L ? and your internal variables should use "rmm.Ez" and not the 3.5a name emqa.Ez finally use a finer time step to better resolve the oscillations with 1 turn/sec and 8 poles you have 4 sinus per turn With that I see a 4V amplitude sinus out -- Good luck Ivar
Phan Van Tung
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Posted: 1 decade ago Mar 10, 2011, 8:31 a.m. EST
Hi Ivar,
I am also working with Comsol to develop a cooling system for a given electric machine. This moment is the starting time with Comsol. Can you let me ask you that is there any geometry database for electric machine provided in Comsol capabilities? Do you have any ideas about this?
Thank you
Hi Ivar, I am also working with Comsol to develop a cooling system for a given electric machine. This moment is the starting time with Comsol. Can you let me ask you that is there any geometry database for electric machine provided in Comsol capabilities? Do you have any ideas about this? Thank you
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Mar 10, 2011, 9:56 a.m. EST
Hi

the DB is only for materials, but there are a few examples of rotary machines in the Model builder and other on the CD's and the main web site as articles

--
Good luck
Ivar
Hi the DB is only for materials, but there are a few examples of rotary machines in the Model builder and other on the CD's and the main web site as articles -- Good luck Ivar
Phan Van Tung
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Posted: 1 decade ago Mar 15, 2011, 3:54 a.m. EDT
Thank you for your reply. But I can't find out any examples of rotating electric model in the Model builder as you said. It would be nice if you could advice me more clearly.
Regarding a cooling system in electric machine that I have done, I feel so confused with many things to start modelling an electric machine with such requirements. As I understand, firstly I should model an electric machine, then add heating physic in Heat transfer module. Being an expert in using Comsol, can you outline generally what should be done in this work?
By the way, those who have ever experienced this problem, please share with me your modelling or experiences.
Thank you.
Thank you for your reply. But I can't find out any examples of rotating electric model in the Model builder as you said. It would be nice if you could advice me more clearly. Regarding a cooling system in electric machine that I have done, I feel so confused with many things to start modelling an electric machine with such requirements. As I understand, firstly I should model an electric machine, then add heating physic in Heat transfer module. Being an expert in using Comsol, can you outline generally what should be done in this work? By the way, those who have ever experienced this problem, please share with me your modelling or experiences. Thank you.
Akmal
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Posted: 1 decade ago Mar 18, 2011, 4:57 a.m. EDT
I try to aswer your question,

1. Add study (Heat transfer)
2. If necessary add cooling fin, it depens and it can be more complex.

3. If not, add boundary condition, convektive cooling and define heat-transfer coefficient etc.

4 Define heat source

and so on..

-akmal
I try to aswer your question, 1. Add study (Heat transfer) 2. If necessary add cooling fin, it depens and it can be more complex. 3. If not, add boundary condition, convektive cooling and define heat-transfer coefficient etc. 4 Define heat source and so on.. -akmal
Phan Van Tung
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Posted: 1 decade ago Mar 20, 2011, 12:00 a.m. EDT
Thank you so much.
Have a nice day!
Thank you so much. Have a nice day!
AH
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Posted: 1 decade ago Jan 15, 2014, 10:14 a.m. EST
Hello Ivar


Im trying to simulate a smiple rotating machine but I have problems with the restulted magnetic fields they are not moving in the right way please see the attchment

You can download my modell through the following link

www.dropbox.com/s/d8pns2qtnrjnaxk/drehstrom_2.mph

Thanks in Advance
Hello Ivar Im trying to simulate a smiple rotating machine but I have problems with the restulted magnetic fields they are not moving in the right way please see the attchment You can download my modell through the following link https://www.dropbox.com/s/d8pns2qtnrjnaxk/drehstrom_2.mph Thanks in Advance

Attachments:

AH
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Posted: 1 decade ago Jan 16, 2014, 5:02 a.m. EST
Hello Aeda

I have the same problems you have or had

Did you solve it ?

I would be thankfull if you could reply

Thanks in advance
Hello Aeda I have the same problems you have or had Did you solve it ? I would be thankfull if you could reply Thanks in advance

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