Yet another DIY AMT

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Another simulated view

So I got the idea to invert the motor and simulate it from the side.
I hope that you get the picture, it is barely half a motor wide.
I believe that the field in the gap is really can be simulated this way.

In the simulated middle view you see the contour at the lower, middle and higher part of the gap. The plot shows the field along that contour. It is only in the middle of the gap the field is even.
 

Attachments

  • inverted.jpg
    inverted.jpg
    63.8 KB · Views: 1,641
  • inverted ans.jpg
    inverted ans.jpg
    83 KB · Views: 1,608
  • inverted plot.jpg
    inverted plot.jpg
    60.6 KB · Views: 1,582
Is this "motor " the same as you started with?
If so,I think your drawing is wrong.
The iron must bee on the same magnet.Your draving shows 2 magnets.
I might be wrong,but i dont think you shuld worry about the magnetic field,to me it looks fine from the first simulations.

Bernt
 
Rounded edges

So what if the edges of the iron rods in the gap were rounded?
First two is with square corners, the last two with rounded corners.

The field is stronger, but also has higher fluctuations.
 

Attachments

  • inverted and shifted ans.jpg
    inverted and shifted ans.jpg
    89.3 KB · Views: 214
  • inverted and shifted plot.jpg
    inverted and shifted plot.jpg
    61.9 KB · Views: 182
  • inverted and shifted rounded ans.jpg
    inverted and shifted rounded ans.jpg
    84.1 KB · Views: 178
  • inverted and shifted rounded plot.jpg
    inverted and shifted rounded plot.jpg
    65.9 KB · Views: 172
Assembling the motor, pt 2.

First I made dummies for the gap, to keep the space open and stopping the magnets from intruding it.
Then mounted the dummies and loaded the first set of magnets.

I will probably load one complete side as the next step. I only got two clamps long enough, so it will have to be it two sessions.
 

Attachments

  • 2013_03_29-496.jpg
    2013_03_29-496.jpg
    546.3 KB · Views: 695
  • 2013_03_29-495.jpg
    2013_03_29-495.jpg
    669.3 KB · Views: 1,156
  • 2013_03_29-494.jpg
    2013_03_29-494.jpg
    665.3 KB · Views: 1,208
  • 2013_03_29-492.jpg
    2013_03_29-492.jpg
    568.4 KB · Views: 1,278
  • 2013_03_29-491.jpg
    2013_03_29-491.jpg
    729 KB · Views: 1,346
  • 2013_03_29-490.jpg
    2013_03_29-490.jpg
    786.6 KB · Views: 1,414
Simulated rods vs solid

In the inverted motor I was able to study what happened with the field with respect to offset or rounded edges of the rods.

What if the iron was solid instead of 3 mm rods with 3 mm space inbetween?

The first three below is the rod simulation and the second three is with solid iron. Note that the layout is just for simulating the field, it is not the real motor.

So the field is actually higher with rods, even if it is not so linear.
 

Attachments

  • rods vs solid 6.jpg
    rods vs solid 6.jpg
    55.6 KB · Views: 158
  • rods vs solid 5.jpg
    rods vs solid 5.jpg
    82.4 KB · Views: 155
  • rods vs solid 4.jpg
    rods vs solid 4.jpg
    52.5 KB · Views: 156
  • rods vs solid 3.jpg
    rods vs solid 3.jpg
    58.3 KB · Views: 201
  • rods vs solid 2.jpg
    rods vs solid 2.jpg
    93.8 KB · Views: 191
  • rods vs solid 1.jpg
    rods vs solid 1.jpg
    43.4 KB · Views: 564
Assembling the motor, pt 3.

So I mounted some more magnets, painted the motors black in order to hide some of the imperfections. Then I made some baffles.

Now I´m waiting for the 3M tape to arrive.
 

Attachments

  • 2013_04_01-555.jpg
    2013_04_01-555.jpg
    847.6 KB · Views: 748
  • 2013_04_01-553.jpg
    2013_04_01-553.jpg
    400.2 KB · Views: 613
  • 2013_04_01-552.jpg
    2013_04_01-552.jpg
    519.2 KB · Views: 573
  • 2013_04_01-548.jpg
    2013_04_01-548.jpg
    486.5 KB · Views: 561
  • 2013_04_01-547.jpg
    2013_04_01-547.jpg
    655.6 KB · Views: 638
  • 2013_04_01-544.jpg
    2013_04_01-544.jpg
    374.8 KB · Views: 638
  • 2013_03_30-517.jpg
    2013_03_30-517.jpg
    527.1 KB · Views: 517
  • 2013_04_01-561.jpg
    2013_04_01-561.jpg
    636.8 KB · Views: 799
First membrane

I thought of having a simple layout at first.
The gap is 120 mm wide so why not have a 7,5 + 2,5 mm layout with 5 mm Alu strips.
The pleats are 7,5 mm deep and 2,5 mm apart.
That´ll be 120/2,5 = 48 pleats.
Unfolded the membrane is 48 x (7,5 + 2,5) = 480 mm.

So I cut a nail strip into 200 mm long strips to build a pleating tool:

2013_04_04-562.jpg
 
Last edited:
I have been calculating a bit.
I use 30 pleats in my latest model,and with 5,5mm stripes i get 3,8 ohm.
I recomend you to use 7,5mm stripes for low impedance and to cover more surface with alufoil.
I have another tool in my mind to get paralel pleats.
Your nailstrip is only 1mm.It might be better with 2,5mm.
Keep up the good work.

Bernt
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.