Maxwell 3D (ANSOFT)

  • Thread starter Grinch
  • Start date
  • #76
Hello,

is there anybody who know how to change the default value of stator winding conductivity (resistivity) in RMxprt design in case of 3 phase induction motor...?
As I know the default material of winding is copper...but i need to change it...

Thank you very much for you reply,

Petr
 
  • #77
3
0
Dear all
I am Working with Maxwell 3d, to simulate Linear induction motor,my email is aliasgharpourmoosa@gmail.com
When setting up a transient solver problem in Maxwell 3D, the following error occurred when running the simulation:

"Could not find the face. There might be an isolated hole in the band"

Does anyone know what this means? When I use the magnetostatic solver the simulation runs fine.
sorry for my English
Thank you
Ali
 
  • #78
1
0
Hi, I'm trying to learn the basics of this program (V13) and haven't had luck with the user's guide. Can anyone explain how I might model the magnetic field of a wire with a current of 1 A in Maxwell 3D? It would be greatly appreciated!
 
  • #79
1
0
hello
I want to simulate an electric motor. I have one broken down and I know what they look like individual parts. It is important to perform simulation of the Maxwell 3D, not the "Rmxprt" because I have a lot of ideas for different rotor designs, and I sketched them in 3D. For three months I look through the documentation and tutorials with ansoft. In no case is similar to the embodiments of my model.
I need your help.
It shows in the Annex, where is my problem:
http://www.scribd.com/doc/102721866/2012-0810-2340

Generally, I know that I need to simulate: magnetic-transient or transient Electric. I suspect that the two simulations to connect in some way. Maybe someone will tell me if I'm wrong?

In the case of transient simulation Electric-like state on the ends of the coil voltage. The input impedance and resistance is needed. Where can I calculate this data? I can generally count on a paper but I doubt that all engineers as the problem in this way.

Does anyone have any suggestions on how to start the simulation?
Regards.
Sorensen
 
  • #80
Hi,

I am using Maxwell 13 and I am trying to simulating a 3 phase 4 pole permanent magnet machine, so far I have managed to get reasonable results however I am still not sure about certain things.

#1 problem that I have is that I managed to excite the winding with a 3 phase current input however I am getting results that do not make sens when I tried to excite the winding with a 3 phase voltage input.

#2 another question that I have is how to determine weather the machine is extracting or absorbing power? ie what is the software's conventional equivalent circuit of a generator/ motor?

Thanks a lot
Annalise
 
  • #81
100
5
For the voltage excitation, you need input the coil resistance. The simulation will not model the resistance if the conductor coil is specified as stranded.

Hi,

I am using Maxwell 13 and I am trying to simulating a 3 phase 4 pole permanent magnet machine, so far I have managed to get reasonable results however I am still not sure about certain things.

#1 problem that I have is that I managed to excite the winding with a 3 phase current input however I am getting results that do not make sens when I tried to excite the winding with a 3 phase voltage input.

#2 another question that I have is how to determine weather the machine is extracting or absorbing power? ie what is the software's conventional equivalent circuit of a generator/ motor?

Thanks a lot
Annalise
 
  • #82
Hi,

i did fill the coils resistance and inductance, and the voltage as a sin input with each phase shifted by 120 degrees... However the current waveforms include kind of a DC offset and I got two of the phases shifted upward and another one shifted downwards. I tried to invert the excitation of the winding shifted downwards to at least get the same DC shift in all the phases but did not work out as well...

I thought maybe I need to set other parameters that maybe are disabled when the coils are excited with current...
 
  • #83
gerbi
Gold Member
179
13
Hello
annalisemalta, this phenomena You are observing is transient state in electromagnetic circuit.
This is pretty similiar to inrush current in transformer. Voltage and flux waves in core are shifted by 90 deg. Now imagine what happends when You switch on voltage. If voltage waveform isn't at it's peak (flux is then at zero crossing - current too) current will have some disorder component in it. It will decline in time with some time constant, and only main component of waveform will remain.

You can check if it's true - just set up voltage excitation in one phase to be at it's peak in t=0 (other phases shifted +/- 120deg).
 
  • #84
Yes there is kind of a transient but even after almost 0.5s the waveforms are very far away from a normal 3 phase without a dc shift. I attached my current results for the time I simulated
 

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  • #85
gerbi
Gold Member
179
13
Rearrange excitation like I said. See if it helps or not. If not.. maybe try with external circuit from Maxwell Circuit Editor ? There are some more possibilities with it.
 
  • #86
Hi everyone,

Need you guys help with Ansoft Maxwell 13. I am currently working on electromagnetic linear actuator as a vehicle suspension system. My design should look like below:
_____
| s |
| h |_____ ____ ______
| a | N | | C | | S |
| f |_____| |___| |_____|
| t |

It will be in cylindrical shape. Hope you understand.
N = north pole (magnet material, Neodymium)
S = south pole
C = coil winding

I already design the geometry in Ansoft. But I do have some question related to Maxwell:

1. How to assign magnetic pole (N/S) to my design.
2. How to assign coil polarity during current excitation.
3. Can we create external force to excite the shaft downward or upward?
4. What type of solver should be used for this kind of design?

Sorry for my english. Appreciate your help.
Eddy
 
  • #87
gerbi
Gold Member
179
13
1. How to assign magnetic pole (N/S) to my design.
2. How to assign coil polarity during current excitation.
3. Can we create external force to excite the shaft downward or upward?
4. What type of solver should be used for this kind of design?

Ad. 1: Assign material (permeant magnet) to object. In it's properties You can select how magnetic coercivity vector is oriented
Ad. 2: by altering current direction. Coil polarity depends on direction of current
Ad. 3: Yes, there is such a posibility (assigning a band with mechanical transient)
Ad. 4: Transient (Magnetic)

One more thing, I suggest reading some tutorials and searching Maxwell On-Line Help for vital information about preparing simulation. If You do not have tutorials write me a PM with your e-mail adress and I will send them.
 
  • #89
100
5
You don't necessarily input extra inductance. The simulation will use the modeled inductance of the coil. Induced current will have 90 degree phase shift from the input voltage.

Hi,

i did fill the coils resistance and inductance, and the voltage as a sin input with each phase shifted by 120 degrees... However the current waveforms include kind of a DC offset and I got two of the phases shifted upward and another one shifted downwards. I tried to invert the excitation of the winding shifted downwards to at least get the same DC shift in all the phases but did not work out as well...

I thought maybe I need to set other parameters that maybe are disabled when the coils are excited with current...
 
  • #90
Hi gerbi,

Ad. 1: Assign material (permeant magnet) to object. In it's properties You can select how magnetic coercivity vector is oriented

It is we change the magnitude value to negative(-)/positive(+). Not really understand what you are suggesting.

Ad. 3: Yes, there is such a posibility (assigning a band with mechanical transient)

I did try to assign the shaft as a band but error come out. "Invalid object selected for band. No objects within the band". How could I assign the shaft in mechanical transient?

Appreciate if you could share with me some tutorials for Maxwell 3D for my reference. Please send to dey_ad@yahoo.com.
 
  • #91
gerbi
Gold Member
179
13
You can change Magnitude but X-Y-Z components aswell. Field with orientation (1x,0y,0z) will be perfect opposite to (-1x,0y,0z).

About band.. You need to close moving object inside other object to which You'll asign a band.

Please, read the tutorials (especialy about Toyta Prius motor) - all basics are explained there.
 
  • #92
"You don't necessarily input extra inductance. The simulation will use the modeled inductance of the coil. Induced current will have 90 degree phase shift from the input voltage."


I know that... my problem is that the shift is a dc shift between the currents of the phases not between the voltage and the current, as in the attached screenshot
 
  • #93
Hi,

regarding the transient plots in Maxwell... What is the Moving1.Toqrue? and when exciting winding by current what is the voltage that is available for plotting? the induced voltage or the terminal voltage?

Thanks
 
  • #94
6
0
Hy Everyone!

I would like to ask for your help. There is a transformer transient tests on which I am doing.
I want to calculate or measure the amount of heat loss in [W] occurs in the core.

How do I do this?
Thanks
Bálint
 
  • #95
gerbi
Gold Member
179
13
What is the Moving1.Toqrue?
Don't know. There is no info on it in help. Try plotting it and see how it behaves.
when exciting winding by current what is the voltage that is available for plotting?
it's voltage induced by the current, across the considered element

I want to calculate or measure the amount of heat loss in [W] occurs in the core.
In transient solver there is a possibility to define core loss model. Go to material properties, from menu choose "core loss type" -> "electrical steel". Some more coefficients are now avaible in your window. At the bottom from the menu choose "calculate properties for" -> "core loss at one frequency". In new window enter data You have (frequency, thickness etc.), You should have it from core material manufarcturer and transformer design data. If You don't know sheet material conductivity, which is not so easy to obtain, go with ~2 MS/m.

Ok, with material properties setup ready go to Maxwell2D/3D -> Excitations -> Set Core Loss. Pick core element (if material props are fine, there should be check in right column).
Make mesh refinement in core (accuracy of losses calculation depends on calculated flux distribution) and solve model.
For results plot core loss vs time in results -> create transient report-> rectangular plot.
 
  • #96
6
0
Don't know. There is no info on it in help. Try plotting it and see how it behaves.

it's voltage induced by the current, across the considered element


In transient solver there is a possibility to define core loss model. Go to material properties, from menu choose "core loss type" -> "electrical steel". Some more coefficients are now avaible in your window. At the bottom from the menu choose "calculate properties for" -> "core loss at one frequency". In new window enter data You have (frequency, thickness etc.), You should have it from core material manufarcturer and transformer design data. If You don't know sheet material conductivity, which is not so easy to obtain, go with ~2 MS/m.

Ok, with material properties setup ready go to Maxwell2D/3D -> Excitations -> Set Core Loss. Pick core element (if material props are fine, there should be check in right column).
Make mesh refinement in core (accuracy of losses calculation depends on calculated flux distribution) and solve model.
For results plot core loss vs time in results -> create transient report-> rectangular plot.

Thanks for your help!

Yes, I found this options and I adjusted the core losses in 25°C(by the "power ferrit" core loss type).
Actually I'm using N87 ferrit core. I already can measure the core loss. The results is very nice :)
The next step what I would like to do is the "Thermal modifier".
By the core loss type I have Power ferrite. There is 3 value (Cm, X, Y). Every value have "Edit thermal modifier" option. In this window how can I adjust the loss for example 100°C?

Thanks!
Best Regards!
Bálint
 
  • #97
6
0
Other quoestion:

The simulation is very slow. 50us transient (0.5us step) takes about 20 hour. I would like to speed up. My toroids dimension is about 50mmx16mm. What is the recomended mesh size (faster simulation/precise caltulation).

My compure:
Intel core i7
6GB 1333mHz RAM

Thanks!
 
  • #98
gerbi
Gold Member
179
13
[..] how can I adjust the loss for example 100°C?

I'm sorry, but I have no expierence in this field. It appears that You'll need to read some articles about material properties of power ferrite. Maxwell help contain no detailed information on this one.

The simulation is very slow. 50us transient (0.5us step) takes about 20 hour. I would like to speed up. My toroids dimension is about 50mmx16mm. What is the recomended mesh size (faster simulation/precise caltulation).

It depends. For some crude calculations (to get familiar with model, results etc) mesh shouldn't be very fine.
For this first few simulations and 3D model about few thousand elements ? Thats my guess. For more detailed calculations few times more, but do not create monstrous mesh because it won't help accuracy much.

Some more hints on mesh:
1) Observe calculated energy error in solution data. If it is below 0,5% You can assume it is quite accurate (very accurate below 0,1%).
2) Do some simulations in static solvers (like Eddycurrent). Mesh is done adaptively then. You can observe which areas have increased meshing and do similary in transient solver manually.
3) Observe results (mostly flux distribution). Field details like increased density (if present) should be visible and look natural.
3) Meshing is one of most important things in FEM, it's better to learn how good mesh looks like.
 
Last edited:
  • #99
hi gerbi,

i have difficulties on assigning current to my coil as it is wounded on cylinder core. When I want to assign current, this error occur "Excitation 'Current 1':Cannot apply Current Excitation to non planar entity". Any tips and help from you.

Thanks
 
  • #100
6
0
Some more hints on mesh:
1) Observe calculated energy error in solution data. If it is below 0,5% You can assume it is quite accurate (very accurate below 0,1%).
2) Do some simulations in static solvers (like Eddycurrent). Mesh is done adaptively then. You can observe which areas have increased meshing and do similary in transient solver manually.
3) Observe results (mostly flux distribution). Field details like increased density (if present) should be visible and look natural.
3) Meshing is one of most important things in FEM, it's better to learn how good mesh looks like.

Thanks gerbi!

I am going to try it!

Maybe have you any experience the distributed mode computing between computers?
I tried, but there is something error message:
"Error: Unable to contact AnsoftRSMService, Reason: ANS_CANNOT_CONNECTTO_ANSOFTRSMSERVICE
Testing Completed.
Error: Some tests have failed.
 

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