Hilden-Brand Magnet Motor

[MeggerMan]

Hi Paul,
I read your peswiki page top to bottom last night and I must say it did get me thinking.

Re. MCE (Magnetocaloric effect) you say that if you change the flux field in certain materials then the temperature will rise or fall.
The bit that is puzzling me is you mention the field going from 1T to 0T and 0T to -1T.
I understood that the field strength has no + or - but it has direction, so it may go from 0T to 1T but not -ve.
A gauss meter will tell you +/- T or mT but can you this is telling you the field direction, if you turn the probe around it will read the opposite polarity.

That small point aside, it would be interesting if indeed the temperature was going up and down in the material so many thousands of times a second.

Regards

Rob

[PaulLowrance]

Hi Rob,

I'll try to clarify. As you know it's the net field within the core that counts. So if the permeability is 100,000 and your apply 0.1 oersted (equates to 0.1 gauss) then the net field within the core would be 100000 * 0.1 = 10000 gauss (1 T).  That's our reference. If you reverse the field then it would be -1 T.

So in all magnetic materials indeed there are always temperature fluxations caused by MCE. Normally these temperature changes are 10's of thousands of a Celsius.  ... I'll create some images and describe this process at my peswiki project and post the link in an hour of so.  This will show exactly why smaller domains equate to higher PE.

Please refer to MEMM thread for a continuation of my reply. Since this is JackH's thread I don't want to disrespect his great work in anyway by distracting or posting other material here   ->

http://www.overunity.com/index.php/topic,1565.msg14481.html#msg14481

Regards,
Paul Lowrance

[JackH]

Hello All,

[gyulasun]

Hi Jack,

I have not built a bifilar coil the size you have referred to but I did it in one layer and in smaller size some years ago.
And I did inductance measurements to find that I got at least 3 - 3.5  times as much self inductance
from the bifilar arrangement than from a non bifilar one. Let me show you a link because it confirms
pretty nicely what I found in my tinkering:
http://www.tesla-coil-builder.com/bifilar_electromagnet.htm

So the same length of wire is used on both nails. The two coils are connected in series, so that the end of (any) one coil is tied to the start of the other coil and the start of the first coil gives one connection and the end of the other coil gives the other connection, as you see in the nails' photo.

Now if you wish to do this in six layers then I think you could wind it first in two layers and figure out which endings or begginings of the second layer are to be connected to that of the first layers'.  If you could use an inductance meter to check the increase in self inductance, then you could decide how to connect the wires of the second layer to that of the first layer, and so on, always to get the increase in the self inductance (I mean by checking the connections right after the second layer is done you cannot fail later which direction you continue winding the parallel wires).

Recently I found an old patent where two coils are placed next to each other in a mirror image symmetrical relation on the same core and they are connected in parallel. Unfortunately I have had no time to check if this arrangement is any better in terms of inductance (hence flux) than a similar bifilar arrangement.  See US patent 4806834 and maybe the simplest to use this link to read it:
http://www.freepatentsonline.com/4806834.pdf

The patent includes a kind of explanation on decreasing the time constant of this arrangement and
increasing the flux if compared to a single coil or a pair of coils in series within the same coil volume.
Nevertheless, if this arrangement is able to insure as much flux as your would-be bifilar six layer coil,
then it would be easier to construct.  It is sure that the time constant of the bifilar set up I refer to above
is higher than the set up in this patent due to the series connections of all the layers (DC copper
resistances add up).

Regards
Gyula

[JackH]

Hello Gyula,