Homopolar Generators (N-Machine) by Bruce de Palma

[sm0ky2]

... if we can make the distance between the center until the edge of the disk "longer", probably we can get the voltage higher.
Ariovaldo

I believe what you will find when researching this subject, is that yes: the larger the disk, the higher the voltage.
  and thicker disks produce more current.

[CANGAS]

It all depends on what you mean by " are ".   

You take me back to the thrilling days of yesteryear.

"It depends on what the meaning of the word is is. "

Really, the meaning of the word is is is.

But, whether or not the meaning of the word is is is is not my main worry.

Magnetic field lines have the same kind of reality as elevation contour lines on a topographic map of terrain. They are convenient mathematical fictions that allow us to describe consistently the direction and the strength of how "test particles" would move in the presence of magnetism. Just as a road really goes nowhere, but we travel along a road, field lines don't represent a "flow" of  magnetism, they simply represent strength and direction of how other things would "flow" in the field. The concept of the field is itself a metaphor, a very useful one.
On a topo map, when the contour lines are close together you know that there is a steep slope in the reality and a ball, for example, would roll in a particular direction (at right angles to the lines and in the direction of lower elevation) and speed (fast where they are close). If the contour lines are far apart, the real place is flat or nearly so and the ball will roll slowly if at all ... but still at right angles to the contour lines.
And just as a standard topo map has contour lines that are well defined (as to the elevation change represented by successive lines) so too does a magnetic field line have a specific definition in terms of mathematical relationships between the quantities of the field and the test particle.

Uhhh, but just because somebody imagined field lines without actually seeing them, doesn't prove that they are not "real". Surely you will agree that everything that any human "sees" is a metaphor for the sensory information that is gathered by human senses and transmitted thru nerves to the brain, then processed into "images" capable of being understood by the soul. Like bro. Freud said, "Sometimes a cigar really is a cigar."

 

Tesla's "rotating magnetic field" is of course composed of stationary fields from separate coils, energized in sequence around a circle. A "test particle" like the Egg of Columbus rotates because it is following the sequence of stationary fields made by the separate coils as they are energized in the rotational sequence. The fields themselves do not rotate. Tesla used 4 coils driven by 2-phase AC in his demonstration to produce the "rotating" total field, but the field no more rotates than would LEDs blinking rapidly in a circular sequence.

Bravo!! Before now, I was uncertain if you understood the distinction.

ETA: Tom Valone did a very interesting experiment that he talks about in the Homopolar Handbook. He actually mounted a simple LED voltmeter arrangement directly to the disk of a homopolar dynamo, connected at the center and the edge. He found that when the voltmeter rotated along with the disk, he could detect no voltage generated. But when the voltmeter was stationary in the laboratory reference frame, connected by the usual radial and axial brushes, he did detect voltage from the rotating dynamo.

I have the book. And I read it too. Maybe twice. Or more. In all the excitement I lost count myself.

Do you think that this proves or disproves Special Relativity? Careful how you answer. Many are afraid of giving the "wrong" answer and losing their paycheck.




Cheers
CANGAS 146

[MarkE]

Why would you get the idea that experiment conflicts with SR?  SR can account for a magnetic field as the result of moving charge due to the charge's FOR.  In order to induce voltage, we need a cross product of a time varying magnetic field across a conductor.  When the voltage detector is placed across a fixed radial section of the disk, the expected induction across that radial is very low as confirmed by the experiment.  But relative to the external contact it is another matter, which the experiment also confirms.

[CANGAS]

Why would you get the idea that experiment conflicts with SR?  SR can account for a magnetic field as the result of moving charge due to the charge's FOR.  In order to induce voltage, we need a cross product of a time varying magnetic field across a conductor.  When the voltage detector is placed across a fixed radial section of the disk, the expected induction across that radial is very low as confirmed by the experiment.  But relative to the external contact it is another matter, which the experiment also confirms.

Why would you get the idea that experiment conflicts with SR?

LOL!

Are you illiterate? You seem to fail to comprehend that I ASKED A QUESTION.

I DID NOT STATE A POSITION! Are you delusional?





CANGAS 149

[MarkE]

LOL!

Are you illiterate? You seem to fail to comprehend that I ASKED A QUESTION.

I DID NOT STATE A POSITION! Are you delusional?





CANGAS 149

LOL.  So, you are not prepared to answer your own question?