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Old 11th September 2013, 11:41 PM   #1
WrineX is offline WrineX  Netherlands
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Default trying to get around FEMM and a push pull magneplanar

hi im trying to design a planar driver, like magnepan , except i want to use a push pull system.

this is what i got so far with magnet rubber band of 5x3mm and the Original 2x6 of magnepan.


the excact strenth is not correct because i really have no clue what the Original strength is. but t gives an idea of dimension and what it does to the gapp. atl least if i understand femm corectly atm.

i only use 2 rows of magnet to see whats going on.


Picture 1

to the left my design to be used with 3-5mm foil instead of wire, and to the right the magnepan design that worked apparantly a little more efficient with wire, something that you can see in femm later on.



single plot of the magnet strenght ? dont know the name fo it. 2.5 mm above the magnets , is sort of the spacing in a mgnepan, or maybe even 2mm, but for now 2.5 mm will do.

Pic 2
my design , wich looks horible in single ended configuration. the gap is to large and the whole thing colapses.

Pic 3 magnepans design, much better , still rugged, but you can see they have verry limited gaplength where the field is strong, could be reason why foil as the coil,not Always works like wanted.


Pic 4 Both designs in push pull.

Pic5 My design in push pull, the with of usable magnet strength has increased allot, when compared to single ended and the magnepan size of magnets.


PIC 6 push pull version of the magnepan magnets.



But the only major problem is , im no expert at this stuff and i can hardly follow FEmm and im already glad i could get this on the screen, but not sure im looking at the right stuff.
So hopefully people that do know something about this matter can assist me a little.

the thing is i want to use foil, sintead of wire. because it allows me to open up more of the metal frame, and its easy to aplly, easy to repair, and without tons of glue allot lighter.
Attached Images
File Type: jpg FEMM1.jpg (221.2 KB, 233 views)
File Type: jpg FEMM2.jpg (56.1 KB, 209 views)
File Type: jpg FEMM3.jpg (48.1 KB, 206 views)
File Type: jpg FEMM4.jpg (208.0 KB, 211 views)
File Type: jpg FEMM5.jpg (94.5 KB, 202 views)
File Type: jpg FEMM6.jpg (90.3 KB, 35 views)
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Old 13th September 2013, 02:52 PM   #2
tyu is offline tyu  United States
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Just some of my info........


Magnepan had to put the pole peace in the back MG .5.6 1.6 an 1.7.....when thay went with foil.... Becase it has less output than the wire........i have put the foil from Magnepan thats used on the tweeters of the MG1.6qr on a pr of MG1s ....an i have re-wired with the 36ga wire thay use for tweeters...on more than one pr of Maggys
I well say it close to 3db diff......in output.......the wire for tweerers is ezy to work with but the bass wire is a bitch.....the foil as you are saying will Be ezer to work with but with less output.........may be your dubbel mag....push-pull setup will give more output out of the foil??...........good luck

Last edited by tyu; 13th September 2013 at 02:55 PM.
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Old 13th September 2013, 11:08 PM   #3
WrineX is offline WrineX  Netherlands
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hmm funny my magnet direction is wrong time to remodel. usec 0-180 degree instead of 90-270 .... well still learning
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Old 14th September 2013, 06:33 AM   #4
solhaga is offline solhaga  Sweden
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Look at the b.n (normal) and b.t (tangential) fields instead of the /B/.
It could also be useful to use the vector plot (view/vector plot/B).
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Old 14th September 2013, 08:26 AM   #5
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I have made FEMM for push pull.
[IMG]Click the image to open in full size.[/IMG]
[IMG]Click the image to open in full size.[/IMG]
[IMG]Click the image to open in full size.[/IMG]
Field is alternating, be careful to place the wires right.

Bernt

Place wires or alufoil as shown here :
[IMG]Click the image to open in full size.[/IMG]

Last edited by båndsei; 14th September 2013 at 08:35 AM. Reason: adding picture
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Old 14th September 2013, 02:59 PM   #6
WrineX is offline WrineX  Netherlands
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Nice model.

ok i redit it and used the other tangential thingy, to display the field.

bandsei what sizes are ur neos and what is the foil to magnet distance in ur drawing>


i settled now for a push pul with in the drawing ceramic 5 magnets, but this will be the way lower magnetic rubber magnet. the thing is that the single ended magnepans uses this type of magnet. so i drawed the same dimensions of the magnepan version to compare what happens if i make my own version. so strength in the graph is not saying much (in Tesla numbers) only comparing the one magnet structure to the other, for the foil i want a wide gap. this is what i got now .


the flux is not much in my gap copared to that neo design and is gone be even lower, but if you compare it with the Original magnepan design its still almost 2 as strong and over a much wider range, wich helps to use foil instead of a wire.

ooh i so want to start building but first have to tackle the 300 euro investment for 200 meter magnet........ hate 160 euro of shipping costs


oh one thing Bandsei, the foil conducter in ur design is Always blocked or at the front or the back. im not sure if it makes any diference, can you model that version with ceramic 5 ?
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File Type: jpg FEMM7.jpg (221.0 KB, 46 views)

Last edited by WrineX; 14th September 2013 at 03:09 PM.
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Old 14th September 2013, 03:21 PM   #7
WrineX is offline WrineX  Netherlands
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Quote:
Originally Posted by solhaga View Post
Look at the b.n (normal) and b.t (tangential) fields instead of the /B/.
It could also be useful to use the vector plot (view/vector plot/B).

hmm if i do that i get this... why does it looks so rugged, and the not push pull looks nice and clean ?



Here the b.n (normal) pictures, can you tell me what is hapenning

first picture is the push pull, and second is the single ended, wich looks far beter ? any idea
Attached Images
File Type: jpg FEMM8.jpg (70.6 KB, 42 views)
File Type: jpg FEMM9.jpg (52.5 KB, 14 views)
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Old 14th September 2013, 03:27 PM   #8
WrineX is offline WrineX  Netherlands
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if i let all the arrows of the magnet direction point down i do get a nice graph like the single ended. BUT if i remember correct the magnets have to reppel eachother if you stack an exact same pannel as this behind the first one.

am i going mad or what? now the foil should be directly behind the magnet. instead of in between? the firsl is way stronger now. hmm
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File Type: jpg FEMM10.jpg (284.0 KB, 36 views)

Last edited by WrineX; 14th September 2013 at 03:34 PM.
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Old 15th September 2013, 01:14 AM   #9
WrineX is offline WrineX  Netherlands
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ok i tried in real life , putting the foil in between the magnets like the above picute, result sucks. field may be 2 times as high but it aint working.i stick with the first push pull with back magnets repelling from the front. its increases sensitivity and lowers distortion. but i still would like to know what the

(normal) and b.t (tangential) fields instead of the /B/.
the vector plot (view/vector plot/B).

exactly means
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Old 15th September 2013, 07:25 AM   #10
solhaga is offline solhaga  Sweden
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Vector plots (from the manual):

"A good way of getting a feel for the direction and magnitude of the field is with plots of the field
vectors. With this type of plot arrows are plotted such that the direction of the arrow indicates the
direction of the field and the size of the arrow indicates the magnitude of the field. The presence
and appearance of this type of plot can be controlled by pressing the “arrows” icon pictured in Figure 2.19."
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