Three-phase magnetic cube

[Circlotron]

Suppose we have a cube of magnetic material and we wind some wire around it. Apply a sine wave to the winding and the magnetic field points back and forth along the axis of the winding.

Then we add a second winding at right angles to the first and supply this second winding with a sine wave 90 degrees phase shifted from the first winding. The vector sum of the two resulting magnetic fields would now point back and forth between the axes of the two windings.

Now suppose we add a third winding on our cube at right angles to both previous windings, and we now supply our three windings with three sine waves each shifted 120 degrees as per a normal 3-phase AC power supply.

What path would the resultant magnetic field now follow?
Would this device be of any practical use?

[Alex Eisenhut]

Suppose we have a cube of magnetic material and we wind some wire around it. Apply a sine wave to the winding and the magnetic field points back and forth along the axis of the winding.

Then we add a second winding at right angles to the first and supply this second winding with a sine wave 90 degrees phase shifted from the first winding. The vector sum of the two resulting magnetic fields would now point back and forth between the axes of the two windings.

Now suppose we add a third winding on our cube at right angles to both previous windings, and we now supply our three windings with three sine waves each shifted 120 degrees as per a normal 3-phase AC power supply.

What path would the resultant magnetic field now follow?
Would this device be of any practical use?

MRI machine for four dimensional beings?

[Jeroen3]

A circular motion inside a quarter orb?
I don't know, what a philosophical question.

[Cyberdragon]

Make the cube hollow and put some sort of metal gyroscope thing in it. Connect a 3-phase transformer and you have a nice desk toy. That is if the magnetic field will make it spin and rotate on the other axis.

[German_EE]

Make the cube hollow then fill it with a mixture of mineral oil and iron filings. My bet is that there will be a small sphere of filings in the middle after a few minutes.

[Alex Eisenhut]

Make the cube hollow then fill it with a mixture of mineral oil and iron filings. My bet is that there will be a small sphere of filings in the middle after a few minutes.

Sure and when the Goa'uld come flying out, what then?

[Cyberdragon]

Apparently they use these for "magnetic tracking". They also come with magnetic cores, but the picture of that took up the whole page.

[Alex Eisenhut]

Apparently they use these for "magnetic tracking". They also come with magnetic cores, but the picture of that took up the whole page.

Years ago there was a university that had something like that. They built a big cage with three room size coils and the pick up looked like that cube. It was to track movements in 3D.

Don't know what happened to that but I'd guess that's all obsolete with the Kinect and stuff like that.

Or...

http://en.wikipedia.org/wiki/Magnetometer#Fluxgate_magnetometer

[T3sl4co1l]

The field vector at the center should trace out a circle, in the [111] plane I think.

Why not figure it out for yourself?  That's what they created math for...

Tim

[Circlotron]

I thought it would trace out a circle with only the X and Y coils energised with 90 deg phase shift, same as sine and cosine on an oscilloscope. Lateral thinking is 1D, this is 3D. 

[ludzinc]

Apparently they use these for "magnetic tracking". They also come with magnetic cores, but the picture of that took up the whole page.

Cyberdragon,

Who supplies those coils?  I'm interested in these for active RF tags...

Thanks!

[German_EE]

"Sure and when the Goa'uld come flying out, what then?"

They drown in the mineral oil. Of course, if Sam Carter was around to supervise the experiment I would substitute baby oil, but I digress 

[calexanian]

I think the turtles start right underneath the cube, And it goes turtles, all the way down...   

[Circlotron]

The field vector at the center should trace out a circle, in the [111] plane I think.

Thinking about it some more, I suspect you are right. It would appear as a circle when looking from one particular corner of the cube down to the opposite corner.

Does anyone know of some graphing software or preferably Open Office Calc add-on that would allow three axis graphing of a series of single points?

[German_EE]

My money is still on a sphere but I will settle for a cube with rounded edges. Think about it, a single coil will squeeze the magnetic field into a cylinder so a coil on all three axis will compress the fields into a single point at the center.

[Richard Crowley]

Curiously reminiscent of the bubble memory design where orthogonal coils (along with permanent magnets) are used to move the magnetic bubbles around the garnet chip.

http://youtu.be/0rqPmjmQOxw

And coincidentally discussed in Dave's latest Mailbag video 
http://www.eevblog.com/2014/10/28/eevblog-677-mailbag/

[T3sl4co1l]

The field vector at the center should trace out a circle, in the [111] plane I think.

Thinking about it some more, I suspect you are right. It would appear as a circle when looking from one particular corner of the cube down to the opposite corner.

Does anyone know of some graphing software or preferably Open Office Calc add-on that would allow three axis graphing of a series of single points?

http://www.wolframalpha.com/input/?i=x%3Dsin+t%2C+y+%3D+sin%28t%2B2*pi%2F3%29%2C+z%3Dsin%28t%2B4*pi%2F3%29+graph

[Alex Eisenhut]

Curiously reminiscent of the bubble memory design where orthogonal coils (along with permanent magnets) are used to move the magnetic bubbles around the garnet chip.

http://youtu.be/0rqPmjmQOxw

And coincidentally discussed in Dave's latest Mailbag video 
http://www.eevblog.com/2014/10/28/eevblog-677-mailbag/

Noooooooooooo!!!! I still have an Intel Bubble Memory reference design kit somewhere.   

[Richard Head]

Seriously, how can the resulting magnetic field be one dimensional when the exciting source is symetrical in all 3-dimensions?
It will have to be a sphere, no maths involved.

[Circlotron]

Curiously reminiscent of the bubble memory design where orthogonal coils (along with permanent magnets) are used to move the magnetic bubbles around the garnet chip.

http://youtu.be/0rqPmjmQOxw

And coincidentally discussed in Dave's latest Mailbag video 
http://www.eevblog.com/2014/10/28/eevblog-677-mailbag/

I first though of this 3-coil configuration about 10 years ago. Seeing the bubble memory stuff jogged *my* memory so I decided to see what other people thought.

[Circlotron]

Seriously, how can the resulting magnetic field be one dimensional when the exciting source is symetrical in all 3-dimensions?
It will have to be a sphere, no maths involved.

If for example a circle leans forward off the page it will have an X,Y and Z component.
And the excitation sources are not symmetrical. e.g. when X and Y are equal but opposite, Z will be zero.
Perhaps "symmetrical" is not the right word.

[Alex Eisenhut]

Seriously, how can the resulting magnetic field be one dimensional when the exciting source is symetrical in all 3-dimensions?
It will have to be a sphere, no maths involved.

What if it's on the surface of a magnetar? What then? 

[Richard Head]

Dunno, never been on a magnetar.

[SeanB]

If you are on a magnetar then looking will probably not be high on the list of things, as you will be stripped of the iron in your blood at incredible speed, and the assorted particles you are made of will be sorted by paramagnetic value, irrespective of what they originally were atoms of. It literally will be happening faster than the impulses can travel to your brain and be decoded into an image and comprehended by the brain.

Being at the epicentre of a nuclear blast ( as in right next to the outer casing) would happen slower.

[Alex Eisenhut]

If you are on a magnetar then looking will probably not be high on the list of things, as you will be stripped of the iron in your blood at incredible speed, and the assorted particles you are made of will be sorted by paramagnetic value, irrespective of what they originally were atoms of. It literally will be happening faster than the impulses can travel to your brain and be decoded into an image and comprehended by the brain.

Being at the epicentre of a nuclear blast ( as in right next to the outer casing) would happen slower.

What if I'm wearing a really good spacesuit?