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Author Topic: Permanent magnet flux gate - SSG idea  (Read 11724 times)

void109

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Permanent magnet flux gate - SSG idea
« on: May 06, 2010, 08:07:41 PM »
This has probably already been hashed out, but it hasn't been obvious to me that that is the case.  Was working with some flux sims and had a notion I'd like to test, but I'll post it here as well.  It seems obvious enough that I'm almost certainly missing some key point.

All bars are modeled as ferrous material with a permeability of 1000, same with the toroid cores.  The magnet I modeled as having a field strength of 7 tesla.  The coil I'm placing on the toroids is modeled as having 400 turns pulsed with 50mA of current.

Ideas?
« Last Edit: May 06, 2010, 08:31:59 PM by void109 »

teslaalset

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Re: Permanent magnet flux gate - SSG idea
« Reply #1 on: May 06, 2010, 09:13:38 PM »
Void, have a look at the patent mentioned in post #188 of this thread:
http://www.overunity.com/index.php?topic=8597.180
Looks like a similar principle.

B.t.w. are you sure about those magnets of 7 Tesla?
I don't think they exists.

gyulasun

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Re: Permanent magnet flux gate - SSG idea
« Reply #2 on: May 06, 2010, 11:06:42 PM »
Hi void109,

The principle in magnetic setups like you show is to block flux in a closed magnetic circuit by making a certain flux-path in the circuit to be a high reluctance for the flux. This is best achieved by exciting that part of the core by current fed into a coil to bring that part to saturate. And to make the interaction between the flux in the main flux path and the fluy created by the saturating coil  the smallest possible, you want to make the core path (which is to be saturated) also a closed flux path in itself, so that the flux created by the exciting coil should be closed in itself, this is why a toroidal or rectangular core for this task is preferred.

I hope I did not describe it too difficult...

This principle is clearly seen in the patent drawings as teslaalset referred to it,  and here is this principle in the so called Bulgarian MEG too, see this thread here (and its next pages):

http://www.overunity.com/index.php?topic=4300.msg134162#msg134162

The "Magnetic bypass" means the core saturation when it is 'ON' and 'OFF' so it can effectively divert the flux of PM1 and PM2 to close in itself, not going through the output coil's core when saturating coil is ON.

Can your magnetic flux simulator program saturate a core? If yes, you may wish to choose a core which needs a smallest current at a certain number coil turns to go into saturation.
(notice: your 7 Tesla magnet is a too strong choice, choose about 1.5T, this is for Neo type N52, from among the strongest choices nowadays.

rgds, Gyula

void109

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Re: Permanent magnet flux gate - SSG idea
« Reply #3 on: May 06, 2010, 11:38:19 PM »
Thanks for the feedback!

I'll take a thorough look at that thread and patent drawings before delving much further into it.  I don't want to repeat past work if its a known failure.

The program I'm using doesn't allow me to specify anything for the cores other than permeability, so its pretty limited in that respect.  I also wasnt sure about neo magnet strength, I'll run the sims again with a strength of 1.25 (you said 1.5 ~ N52 neo, I have N48's around here).  I'm not sure what to use for the flux path materials, i was thinking of the stuff Bruce_TPU (Flux bars) was molding in another thread.

void109

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Re: Permanent magnet flux gate - SSG idea
« Reply #4 on: May 06, 2010, 11:47:05 PM »
Hrm - perhaps you could recommend another flux modeling software?  Here are the results from changing the neo to 1.25 teslas and the current to 1uA.  Hard to swallow that so little current could block the flux.  So if you can recommend a different software package, that'd be great. :)

gyulasun

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Re: Permanent magnet flux gate - SSG idea
« Reply #5 on: May 07, 2010, 12:40:39 AM »
Unfortunately the better simulators are very expensive, over in the $15-20k, unfortunately.  Look for Infolytica (http://www.infolytica.com/ ) or Maxwell 3D ( http://www.ansoft.com/products/em/maxwell/ ) Of course there are other products too.  Perhaps asking for info at a local university campus EE department would also be of help?

gyulasun

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Re: Permanent magnet flux gate - SSG idea
« Reply #6 on: May 07, 2010, 12:52:03 AM »
Quote from: void109 link=topic=9140.msg240512#msg240512 A=1273181899
Thanks for the feedback!

I'll take a thorough look at that thread and patent drawings before delving much further into it.  I don't want to repeat past work if its a known failure.

The program I'm using doesn't allow me to specify anything for the cores other than permeability, so its pretty limited in that respect.  I also wasnt sure about neo magnet strength, I'll run the sims again with a strength of 1.25 (you said 1.5 ~ N52 neo, I have N48's around here).  I'm not sure what to use for the flux path materials, i was thinking of the stuff Bruce_TPU (Flux bars) was molding in another thread.

The Bulgarian MEG is reported to be a COP>1, about a COP of 2.  Member  Getca in the thread I referred to you above also reported COP>1. 

For the flux path ferrite is a good choice but it is very difficult to machine if it is needed, and often you are limited to off the shelf sizes. Yes the method Bruce showed is also viable. Just think of eddy current minimization that is the most important here in this setup.

teslaalset

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Re: Permanent magnet flux gate - SSG idea
« Reply #7 on: May 07, 2010, 01:26:49 PM »
Hrm - perhaps you could recommend another flux modeling software?  Here are the results from changing the neo to 1.25 teslas and the current to 1uA.  Hard to swallow that so little current could block the flux.  So if you can recommend a different software package, that'd be great. :)

I use FEMM for this, although it is only able to simulate in semi 3D (depth of the 2D is adjustable before calculation).

FEMM can be found here:
http://www.femm.info/wiki/HomePage

It's free of change.

What program did you use for your initial simulation as posted here?
« Last Edit: May 07, 2010, 03:32:52 PM by teslaalset »

NTesla

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Re: Permanent magnet flux gate - SSG idea
« Reply #8 on: May 08, 2010, 10:42:44 AM »
The past few days I have been thinking about a similar concept! Essentially an Ecklin generator that uses toroids as flux switches instead of the mechanical 'flux blocker' i.e a solid state Ecklin generator (which in many ways is like the M.E.G).

You would pulse the torroid to create the equivalent of an air gap between each pole of the magnet and the iron core. The toroid would be wrapped with copper wire AROUND the contact surfaces of the magnet and iron core (like your pictures shown) so that the magnet and iron core would be in contact with the material of the torroid.

I was thinking of testing the concept using a C core (2 toroids only), mounting the torroids horizontally (instead of vertically like your pictures show to reduce undesireable flux paths) and then if I could generate reasonable current in the coil, then making an I core with 4 toroids (one per pole of the 2 x N/S magnets, preferably in a horseshoe configuration (rare for Neodymiums)).


 ;D
« Last Edit: May 08, 2010, 11:21:46 AM by NTesla »