[Atomic-S (OP)]

Consider the following apparatus:

As I was saying....I am having difficulty getting the image to post.

[syhprum]

I presume that toroidial body is magnatized and rotating I would expect that the magnetic field would remain confined to this core and very little would leak out to generate current in the coil.
This appears to be half of a torordial transformer one of the virtues of which is little stray field.

[Geezer]

I presume that toroidial body is magnatized and rotating I would expect that the magnetic field would remain confined to this core and very little would leak out to generate current in the coil.
This appears to be half of a torordial transformer one of the virtues of which if little stray field.

I agree. A change in the magnetic flux in the coil is required to generate a current. In this configuration the magnetic flux in the coil never changes.

[RD]

If a spherical magnet was rolling around inside the hollow toroid I believe a current would be generated, (need more coils though) ... http://www.faqs.org/patents/app/20090256443  [ parasitic generator ? ]

[Geezer]

If a spherical magnet was rolling around inside the hollow toroid I believe a current would be generated, (need more coils though) ... http://www.faqs.org/patents/app/20090256443  [ parasitic generator ? ]

One coil would be sufficient to generate a current, but it would not be a very effective generator.

[Atomic-S (OP)]

Excuse me for not explaining myself; i had problems with getting the picture uploaded and never got to explaining it. What we have here is a hollow permanently magnetized nonconducting toroid (think powdered iron bonded by a resin), sort of the shape of the tube inside certain types of tires, the internal field circulating about the axis, as indicated by the turquoise-colored arrows (for a bigger picture, click on the picture). The field is internal to the material of the toroid, and thus exists strongly within the wall of the toroid but is zero inside the hollow cavity of the toroid, and also outside the toroid.  The toroid has one other feature: a lot has been sawed through from outside toward the toroid axis, in a plane containing the axis, and another short slot cut into one side nearby. This small slot must be thought of as being lined with a grommet of anti-magnetic material such as a superconductor so that the magnetic flux is fully eliminated from it, being diverted around it. A straight electrical conductor passes through the small side slot from L to S1.  Another straight electrical conductor runs from S1 to S2, and is slip-jointed at both points so that it can swivel at S1 and can slide on the conducting ring at S2. The conducting ring itself remains stationary. A wire runs from the conducting ring to the bulb, and then a wire from the bulb to L completes the circuit. All portions of the apparatus are stationary except the conductor from S1 to S2, which rotates as indicated by the orange arrow. This causes it to cut the field that jumps the gap in the toroid, thereby inducing a voltage. Note that the field in the gap is everywhere the same direction and is also stationary, so that this apparatus generates a direct current. Note too that the field in the gap exists between the ends of the tubular toroid structure, but does not significantly exist within the hollow core of the toroid.  All the action takes place in that small region where the conductor S1==S2 is directly between the ends of the toroid wall. Note that the conducting circuit does not encounter a significant magnetic field anywhere else.

So I think we can agree that what we have here is a DC generator of straightforward operational principles.

Now we are going to do an experiment. Let us mount the entire apparatus upon a board and put it within another apparatus (not shown) that spins the whole thing about the conductor L--S1, at a speed that exactly opposes the speed of the generating conductor S1--S2.  The result will be that now that the conductor S1--S2 is stationary, but everything else is spinning.

The question is, does the bulb continue to light or not?

Arguments saying it should not light are as follows: Because conductor S1--S2 is now stationary, its presence within the field jumping the gap should generate nothing. Many other conductors are of course now moving, but they are not in any field, so likewise should generate nothing.  Conclusion: The bulb does not light. And if that conclusion is correct, then this apparatus would have application as an electromagnetic gyroscope.

[Geezer]

Maybe you should try to describe the principle on which it operates. I got sort of lost while reading your word picture.

[syhprum]

Does the magnetized object have to be in the form of a toroid ? for your thought experiment would not a rod of quasi infinite lenght be better ?
In what manner would it be magnetized would it have poles at its ends or are the poles at either side of the slot ?.
 

[Atomic-S (OP)]

Does the magnetized object have to be in the form of a toroid ? for your thought experiment would not a rod of quasi infinite lenght be better ?

It is of questionable validity to use a [hollow -- remember the toroid is hollow] rod of quasi-infinite length. Such a rod is probably an acceptable simplification for the case when the apparatus except for Conductor S1--S2 is stationary, but it may not be a valid simplification in the case when S1--S2 is stationary and everything else is spinning about L--S1.  And the reason can be seen by reaching the quasi-infinite hollow rod via taking it as the limit of the case in which the toroidal diameter increases without limit. The problem is that in the case when the apparatus spins and the conductor S1--S2 is stationary, as you take that limit, the linear speed of the part of the toroid farthest from the conductors also increases without limit. Remember that it is magnetized internally. I am unsure if we may validly allow the speed of parts of this magnetized object to increase without limit, without introducing some kind of error into the analysis. For this reason, I work on the assumption that the toroid remains at a fixed diameter. However, we may validly assume that that diameter is substantially larger than the dimensions of the conducting circuit.

In what manner would it be magnetized would it have poles at its ends or are the poles at either side of the slot ?.

It would be magnitized like if you started with just the toroid, made of a high-hysteresis material (as permanent magnets are made of), wrapped a coil around it in the usual manner (that is, each turn of the coil lies nearly in a plane that contains the toroid's principle axis, and circles around the outside and also through the doughnut hole), then applied a strong current to magnetize it, then remove the coil. The resulting B field therefore lies within the material (but not inside in the hollow interior) and points everywhere at right angles to the principle toroid axis, except of course near the small outside slit, where it diverts around it as shown by blue lines in the picture.

[Atomic-S (OP)]

Concerning the pole ends: Pole ends exist on either side of the gap that is sawed through where the conductor S1--S2 goes. Pole ends do not exist anywhere else.

[Atomic-S (OP)]

Apparently what I have said thus far is largely incomprensible.  I start over: I start o ver with a somewhat redesigned apparatus that may be easier to understand.

Consider a bar of ferromagnetic powder mixed with a plasticly deformable resin. (This will be magnetically susecptible without being electrically conductive). Now apply the blacksmith's hammer to one end, making a flat taper like when forging a chisel. Now let the smith further form the end by bending the now straight and thin end into a crescent, and let him roll the crescent around so that its two corners meet at the tips, but the edges of the wedge remain elsewhere somewhat separate. This constitutes a hollow cone at the end of the bar except that one side of the cone, where the seam would have been, is left partly open as an access port.  Now imagine forging the other end of the bar the same way.  Now imagine bending the bar around in a loop so that the two cones face, and are brought face-to-face except for a narrow gap between the two faces (see Figure 2, attached picture).

[Atomic-S (OP)]

Now, imagine that this object is magnetized toroidally, so that the field follows the lay of the material, traveling along the length of the bar (which is of course now in a loop), into a conical end, then jumps the narrow gap between the conical ends, then through the other conical end, and back around. (Bluegreen arrows in attached picture). The field is so arranged that it remains within the material of the bar (but not within the hollow spaces inside the cones) everywhere except in the narrow gap between the conical faces. In partricular, the field travels around (within the material), not through (within the air) the unclosed seams that form the access apertures into the cones. As to objections that this would not be possible because if the field can jump the gap between the circular conical faces then it could also jump the unclosed seams: First, the gap between the faces can be thought of as being much narrower than the width of either seam opening. Second, the alignments of the individual grains in the magnetic material could be so arranged that they purposefully distort the field so as to bypass the seam apertures but then focus the field across the gap between faces, and third, even if all this is not convincing, the structure can be thought of as being insulated by a coating of superconductor everywhere except upon the faces of the cones, guaranteeing that the field cannot exit anywhere else. 

Now, within the gap between the faces, a straight conductor is placed that will pivot at the point S1, and contact the contact ring at point S2. This conductor will sweep circularly around, pivoting at S1, sliding at S2, cutting the magnetic field between the conical faces and thereby generating a current that will pass through the bulb and back via a wire through a seam aperture, in which no field exists to the pivot point. This is a DC generator.

Note that the blue dashed line is the axis for this rotation, and that at this juncture in the experiment, the sweep arm is the only electrically active moving part. (Mechanism for supporting and moving the arm is not shown for simplicity).

[Atomic-S (OP)]

Here is another view of the same apparatus. In this view, the sweep arm and contact ring are seen edgewise and not easily distinguished, but it shows how they are aligned with respect to the gap between the cone faces.

[Atomic-S (OP)]

Another view of the apparatus, as seen by the bug that you will observe in Figure 3.

[Atomic-S (OP)]

I hope all that is clear, and show how a conductor sweeping through a magnetic field that forms a cylinder about its rotational axis, generates a constant EMF as it cuts the magnetic lines of force, which is then collected at the contactor ring and sent though a circuit.  And that no field encounteres the circuit anywhere else in the system.

[Atomic-S (OP)]

But now comes the important part of the experiment: We repeat it, after first having mounted the apparatus into another (not shown) that will rotate the entire apparatus about the same axis (blue dashed line) that the sweep arm rotates about, but in the opposite direction and at the same speed. The result is to make the sweep arm stationary, and everything else moving.

An electromagnetic analysis of this situation seems to indicate that no current should now flow, based upon the following considerations:  The field is present in the gap as before, but the conductor that cuts it is now stationary, therefore no EMF.  As for the rest of the circuit, it is now moving, butit is not moving through any field, therefore its EMF also is zero. Result? No current.

So the question is, is this correct or not?  And if it is not, what is the correct explanation of the electrodynamics involved?

[Geezer]

Let's see if I have this right:

You have a bar magnet formed into a circle with a gap. There is a strong field in the gap.

You put a conductor in the field and a current flows through the conductor and around an external circuit.

What I don't understand is why current would be induced in the conductor. That will only happen if a force is applied to the conductor to make it travel through the field. What is making the conductor move?

[Atomic-S (OP)]

The conductor, meaning the rod between S1 and S2, moves under an external influence that is not depicted, pivoting at the point S1 and sliding along the contactor ring at S2, thereby sweeping through the magnetic field that exists between the circular faces of the conical pole pieces. In the first version of the experiment, the conductor from S1 to S2 is the only moving electrical part. In the second version of the experiment. it is the only stationary part, everything else moving instead.