Not OU but...

[thx1138]

I've been looking at manipulating Bloch walls and magnetic reconnection lately in regards to the Hendershot build I'm working on and this idea kind of slapped me in the back of the head. I haven't really thought it through. I'm kind of wondering if I should spend any time on it or not.

It wouldn't, strictly speaking, be over unity but would it produce a net gain. Here it is:

Build a new controller circuit board for a hard disk drive that is geared toward writing large swathes of magnetic fields on the platters rather than trying to get the most areal density as possible, i.e. stripes rather than points. Then write an alternating "010101" or "000111000111000111" pattern on a single track of the drive.

It takes the same amount of power to spin the drive and run the controller regardless of whether we are reading or writing as long as we aren't pushing and pulling the read/write head around. So position the head and write the pattern to the platter. Then read it back 1K, 10K, 100K, or a million times.

Writing the pattern would occur only once, maybe 3 or 5 times to strengthen the field on the platter. Then read it back for hours on end all the while maintaining the read head in the same position. We might have to rewrite the pattern occasionally to keep the field strength up but I'm think something along the lines of every million reads it would be rewritten.

The circuitry on the controller would feed the alternating 0's and 1' s into a coil from which to extract power.

I realize that at first glance this would produce minuscule amounts of power but I'm thinking along the lines of the Faraday disk or the Tesla Unipolar dynamo but with today's off the shelf technology.

Would there be any net gain here? Thoughts?

We've got some amazing technology laying around in our junk drawers that we mostly ignore while pursuing other things. Maybe put some of it to work.

I don't know enough about the specifics of hard drive controllers to do it right now but I'm wondering if it is worth spending the time to learn it.

[Slider2732]

That's really quite fascinating as a concept.


I think you mean as in rotating magnetic field areas of the disk in big chunks ?
Though, HDD's employ some very good shielding with their cases. Unless it was to run in cabriolet mode ? lol, top off, open to the sunshine.


Another way of using such a technique, may be to send the data to a DAC and on to a MOSFET or similar ?
As such, you could have all sorts of data trains feeding in, based on track number.
It would be similar to an old record player in function, or, I guess a CD, or even a function generator...but infinitely programmable.
The point being that if a certain wave was tweaked in the right way, you could alter it to be exactly at resonance with a transmitting coil or other circuit components. At exactly 50ms (or whatever) the waveshape could change to offset a null point. A regular square wave train of 0's and 1's would be just the same as a sig gen, but what if your HDD track snapped out to a sine wave mid way in the cycle.
Most would likely say to use a microcontroller for that, but, yes, reusing old tech is a great route and may set up mechanical resonances that were wholly unexpected..

Hmm, well I hope I have the idea somewhat right. Looking forward to more of your thoughts on it.

[BEP]

Would there be any net gain here? Thoughts?

My thoughts...

You will only see net losses.

The reason is that storing a magnetic field pattern is no different than mounting magnets on a rotor/disk.

Now, when you apply rotational energy to those patterns so they can create induction in the read-head or whatever pickup you devise, the energy picked-up will be whatever you are applying to cause rotation less losses in the motor, driving circuits and pickup.

You can build a generator consisting of magnets mounted on a disk with coils for pickup getting the same effect, net losses.

Using the little magnets you create by writing zeros and ones just means your signal will be a higher frequency and much lower energy for powering a load.

I'm not being pessimistic, just realistic.

[Smudge]

When a PM or magnetized ferro material is within an external magnetic field that is increasing with time, the magnetic energy stored in the sum of that field and the field from the PM can also increase with time.  The increase in magnetic field energy comes from the quantum world of space, from whatever keeps electrons spinning or orbiting.  If we could capture that increase in magnetic energy we would indeed have an OU machine.  We do capture that energy when magnets attract each other and we use the force and movement to do work.  Unfortunately we give all that energy back to the quantum world when we then pull the magnets apart.

So writing tiny "magnetic ones" onto a disc or tape that moves through a magnetic field so that they see an increase as they approach the magnet supplying that field, but then get erased before they see the decreasing field after they have passed by, could well be a route to OU.  In effect the magnet attracts the tiny magnets on the tape thus pulling the tape along, but that attraction doesn't create drag because of the erasure.  So IMO it is worth experimenting.

Smudge 

[thx1138]

My thoughts...

You will only see net losses.

The reason is that storing a magnetic field pattern is no different than mounting magnets on a rotor/disk.

Now, when you apply rotational energy to those patterns so they can create induction in the read-head or whatever pickup you devise, the energy picked-up will be whatever you are applying to cause rotation less losses in the motor, driving circuits and pickup.

You can build a generator consisting of magnets mounted on a disk with coils for pickup getting the same effect, net losses.

Using the little magnets you create by writing zeros and ones just means your signal will be a higher frequency and much lower energy for powering a load.

I'm not being pessimistic, just realistic.

You're right. I did some "back of the envelope" calculations and it would take too many reads to regain what was spent turning the motor even with the head locked in place and using no energy to position it. Speeding up the reads, i.e. more bits/second, creates higher impedance and it's a losing battle.

While it could accumulate charge it would never reach break even. It might reach break even with ~1,000 read heads on a 10,000 RPM drive and that is physically possible because they are so small but then we get into manufacturing cost, etc.

Oh, well.

[T-1000]

If we could capture that increase in magnetic energy we would indeed have an OU machine.  We do capture that energy when magnets attract each other and we use the force and movement to do work.  Unfortunately we give all that energy back to the quantum world when we then pull the magnets apart.

Disrupting magnetic field when you need pull magnets apart would do a trick. Simple capacitor discharge even can be used to temporary reverse one of magnetic poles in soft intermediate material between magnets for creating reflective force impulse.
It is all about how you approach problem...