The bistander thread

[Turion]

Axial force (here the attraction of the magnet to the coil core) doesn’t PRODUCE torque. It REQUIRES torque to overcome. Stick a magnet to a metal plate and try to push it sideways an inch.. Now take a metal bar with 12 of those magnets mounted to it and attach the magnets to a metal table top and try to push them sideways an inch.

You keep trying to put your words in my mouth. I never said cogging was caused by axial force. I said the attraction of the magnets to the cores causes cogging.

You hear what you want to hear and read what you want to read.

Any displacement of the rotor from this position (alignment of magnet to coil core) results in cogging torque which attempts to re-align the rotor to this position."
This is what the study said and I absolutely agree. Don't you? It was YOUR study. You found it. You don't want to have a discussion. You want to trick me into trying to defend a position I have never taken.

Besides, axial force is defined (I believe and could be wrong) basically force parallel to the axis. We are dealing with MORE than just an axial force here. Take your lazy susan in your video, glue a big magnet on the plastic, and then see how well it rotates past that metal frame. The weight of the magnet would be your axial force would it not? BUT WHAT IS THE ATTRACTION TO THE MAGNET? IF YOU WANT TO CALL THAT AXIAL FORCE, FINE, BECAUSE IT PROBABLY IS, BUT NOW YOU HAVE A PROBLEM DON'T YOU? It will require some "torque" to overcome.

[bistander]

Axial force (here the attraction of the magnet to the coil core) doesn’t PRODUCE torque. It REQUIRES torque to overcome. Stick a magnet to a metal plate and try to push it sideways an inch.. Now take a metal bar with 12 of those magnets mounted to it and attach the magnets to a metal table top and try to push them sideways an inch.

You keep trying to put your words in my mouth. I never said cogging was caused by axial force. I said the attraction of the coils to the cores causes cogging.

You hear what you want to hear and read what you want to read.

Any displacement of the rotor from this position (alignment of magnet to coil core) results in cogging torque which attempts to re-align the rotor to this position."
This is what the study said and I absolutely agree. Don't you? It was YOUR study. You found it.

"Any displacement of the rotor from this position (alignment of magnet to coil core) results in cogging torque which attempts to re-align the rotor to this position."
This is what the study said and I absolutely agree. Don't you? It was YOUR study. You found it."

Yes, I agree. But that has nothing to with axial force. Why do you think it does?

Put 10 pounds on a lazy Susan which has a frictionless bearing. How much torque does it take to rotate it at 5 RPM? Increase it to 100 pounds. How much torque does it take to rotate it at 5 RPM? Where is this "It REQUIRES torque to overcome."? Answer is nowhere. Torque is not related to axial force.

Why do you think the rotor "attempts to re-align the rotor to this position"? Because that position is the point of zero torque or Stable Detent, nothing to do with axial force.. in fact, the axial force is already neutralized by Newton's equal and opposite force.

Instead of magnets on a steel plate, use gravity (weights) on flat slick ice sheet. Now there is a downward force of say 100 pounds. How much force does it take to push it sideways? Increase it to 1000 pounds, how much sideways force? In both cases, the sideways force is independent of the vertical force. When you attempt to push the magnet sideways there are non perpendicular forces which resist the applied force, similar to the circumferential components mentioned in the article.*
bi
*edit

The magnet on steel plate may not be similar to the article circumferential components. The article below claims the resistance to lateral movement of a magnet on a steel plate is due to friction.

https://www.kjmagnetics.com/blog.asp?p=magnetic-forces

[Turion]

"Any displacement of the rotor from this position (alignment of magnet to coil core) results in cogging torque which attempts to re-align the rotor to this position."
This is what the study said and I absolutely agree. Don't you? It was YOUR study. You found it."

Yes, I agree. But that has nothing to with axial force. Why do you think it does?

I never said it DOES. This is you, one more time, trying to put words in my mouth. It has to do with cogging.

Put 10 pounds on a lazy Susan which has a frictionless bearing. How much torque does it take to rotate it at 5 RPM? Increase it to 100 pounds. How much torque does it take to rotate it at 5 RPM? Where is this "It REQUIRES torque to overcome."? Answer is nowhere. Torque is not related to axial force.

Gosh, you conveniently FORGOT the magnet on the Lazy Susan and the METAL TABLE under it. LOL. Another example of you twisting or manipulating what I said to try to appear correct.

Why do you think the rotor "attempts to re-align the rotor to this position"? Because that position is the point of zero torque or Stable Detent, nothing to do with axial force.. in fact, the axial force is already neutralized by Newton's equal and opposite force.

Why does it try to realign? Because of MAGNETIC ATTRACTION. Neither torque nor axial force have anything to do with it. That's just you blowing smoke to obfuscate the truth.

Instead of magnets on a steel plate, use gravity (weights) on flat slick ice sheet. Now there is a downward force of say 100 pounds. How much force does it take to push it sideways? Increase it to 1000 pounds, how much sideways force? In both cases, the sideways force is independent of the vertical force. When you attempt to push the magnet sideways there are non perpendicular forces which resist the applied force, similar to the circumferential components mentioned in the article.*

Unfortunately we don't just have a weight on ice. The ice isn't ATTRACTED to the steel plate you set on it, now is it? That's the difference. There is magnetic attraction to overcome, not a weight sitting on ice. Sorry.

[bistander]

I never said it DOES. This is you, one more time, trying to put words in my mouth. It has to do with cogging.



Gosh, you conveniently FORGOT the magnet on the Lazy Susan and the METAL TABLE under it. LOL. Another example of you twisting or manipulating what I said to try to appear correct.



Why does it try to realign? Because of MAGNETIC ATTRACTION. Neither torque nor axial force have anything to do with it. That's just you blowing smoke to obfuscate the truth.



Unfortunately we don't just have a weight on ice. The ice isn't ATTRACTED to the steel plate you set on it, now is it? That's the difference. There is magnetic attraction to overcome, not a weight sitting on ice. Sorry.

ATTRACTION definition
noun

the force by which one object attracts another

https://www.vocabulary.com/dictionary/attraction

In physics, attraction may refer to gravity or to electromagnetic force.

https://simple.m.wikipedia.org/wiki/Attraction

Turion,
Your magnetic attraction at TDC is an axial force. Period. Regardless of the orientation, horizontal or vertical. So in the vertical orientation, that axial force is no different than gravity. On the lazy Susan, the gravitational force is axial to the plane of the disc just like the magnetic attraction force is axial to the plane of your rotor. This is a valid analogy.

You said:
"I never said it DOES. This is you, one more time, trying to put words in my mouth. It has to do with cogging"
at the beginning of you reply above. I don't understand. Are you then denying that the magnetic attractive force at TDC is axial in direction? Why did you quote that paragraph and tell me that you agree and ask me if I agree?

You say "Why does it try to realign? Because of MAGNETIC ATTRACTION. Neither torque nor axial force have anything to do with it. That's just you blowing smoke to obfuscate the truth."
I can only conclude that you do not believe that magnetic attraction is a force. Is this the case?

or/and

Forces do not have directions. Is this what you think?

or/and

Something other than torque can cause rotation. Is this what you think?

Please clarify.

Then you say:
"Unfortunately we don't just have a weight on ice. The ice isn't ATTRACTED to the steel plate you set on it, now is it? That's the difference. There is magnetic attraction to overcome, not a weight sitting on ice. Sorry."

From reading that article from K&J Magnetics, I believe that if you were to coat your steel plate with a thin coating of very slippery ice, your magnets would still exhibit the normal force, meaning perpendicular to the plane of the plate, but have almost no resistance to lateral movement. That would shoot down your argument, wouldn't it, or if not, why?
bi

[Turion]

I have answered all your questions and you keep twisting my words to support your erroneous conclusions. This is not a discussion. This is you perverting the truth to win at all costs. When you are proven wrong, you just ignore it and go on. There is nothing to be gained by arguing with someone who is being paid to cloud the truth.

Your own study supports my contentions yet you do everything you can to twist my words.

Any displacement of the rotor from this position(alignment of magnet to coil core) results in cogging torque which attempts to re-align the rotor to this position.”

END of discussion

[bistander]

I have answered all your questions and you keep twisting my words to support your erroneous conclusions. This is not a discussion. This is you perverting the truth to win at all costs. When you are proven wrong, you just ignore it and go on. There is nothing to be gained by arguing with someone who is being paid to cloud the truth.

Your own study supports my contentions yet you do everything you can to twist my words.

Any displacement of the rotor from this position(alignment of magnet to coil core) results in cogging torque which attempts to re-align the rotor to this position." PERIOD

END of DISCUSSIONAny displacement of the rotor from this position(alignment of magnet to coil core) results in cogging torque which attempts to re-align the rotor to this position."

So you admit defeat. You can't justify your erroneous statements and theories with reason and logic or experimental proof which can withstand scrunchy, so you run away. Still not proving what you claim.

Any displacement of the rotor from this position(alignment of magnet to coil results in cogging torque which attempts to re-align the rotor to this position." PERIOD

END of DISCUSSIONAny displacement of the rotor from this position(alignment of magnet to coil core) results in cogging torque which attempts to re-align the rotor to this position."

Why have you said this twice? It's consistent with all I've been saying. And it is clearly depicted on the graphs that I've referenced, as is zero torque at TDC.
bi.

END of DISCUSSION

OK. Wind some more coils and see if that helps.
Good luck.

[Turion]

I said the attraction of the rotor magnet to the coil at TDC causes cogging. The expert YOU produced agrees.

“Any displacement of the rotor from this position(alignment of magnet to coil core) results in cogging torque which attempts to re-align the rotor to this position.”

I have said that the visible effect of cogging goes away at speed but that magnetism or the magnetic attraction NEVER goes away. You have admitted both are true.

I am SO defeated! LOL.

[bistander]

I said the attraction of the rotor magnet to the coil at TDC causes cogging. The expert YOU produced agrees.

“Any displacement of the rotor from this position(alignment of magnet to coil core) results in cogging torque which attempts to re-align the rotor to this position.”

I have said that the visible effect of cogging goes away at speed but that magnetism or the magnetic attraction NEVER goes away. You have admitted both are true.

I am SO defeated! LOL.

Turion,

Can not you read? It says 'Any displacement of the rotor from this position(alignment of magnet to coil core)".

*Displacement from* means it is not at TDC. So your statement of "I said the attraction of the rotor magnet to the coil at TDC causes cogging." The expert YOU produced agrees." is untrue. The expert did not say and does not agree with "attraction of the rotor magnet to the coil at TDC causes cogging." His graph shows zero cogging torque at TDC. Zero cogging torque means no cogging. When at TDC there is only axial force between the magnet and core. There is no torque imparted to the rotor and therefore no load placed on the motor at TDC from the attractive force between the magnet and core. The expert"s article supports that.
bi

[Turion]

So if there was no attraction of the magnet to the core at TDC cogging would still exist? Is that what you are saying? No, because the magnetic attraction causes cogging. Without it cogging would not exist. Period.

“Any displacement of the rotor from this position(alignment of magnet to coil core) results in cogging torque which attempts to re-align the rotor to this position.”

I NEVER SAID cogging takes place at TDC. NEVER. I said the magnetic attraction of the magnet to the core causes cogging. It does. Without that attraction, cogging would NOT exist. I’m right. You’re wrong. Get over it.

And how about my “moment in time when they align and magnetic attraction is the greatest” which you made fun of me for. The expert said THAT is true also and you continue to ignore it even though this is the third time in the last couple days I have reminded you.

”The truth? You can’t handle the truth!”

[bistander]

So if there was no attraction of the magnet to the core at TDC cogging would still exist? Is that what you are saying? No, because the magnetic attraction causes cogging. Without it cogging would not exist. Period.

“Any displacement of the rotor from this position(alignment of magnet to coil core) results in cogging torque which attempts to re-align the rotor to this position.”

I NEVER SAID cogging takes place at TDC. NEVER. I said the magnetic attraction of the magnet to the core causes cogging. It does. Without that attraction, cogging would NOT exist. I’m right. You’re wrong. Get over it.

And how about my “moment in time when they align and magnetic attraction is the greatest” which you made fun of me for. The expert said THAT is true also and you continue to ignore it even though this is the third time in the last couple days I have reminded you.

”The truth? You can’t handle the truth!”

If somehow magnetic attraction at TDC could be eliminated without disturbing magnetic attraction at all other rotor positions, cogging would remain unchanged. Cogging torque at TDC is zero.

You claim there is a load on the motor resulting from magnetic attraction at TDC. A load on the motor must come from torque on the rotor. Torque on the rotor from magnetic attraction is cogging. Follow the logic.
You say "moment in time when they align and magnetic attraction is the greatest".
So what? At that moment the cogging torque is zero and the greatest magnetic attraction is strictly an axial force which has been offset by Newton's equal and opposite force. Also, although academic, axial force does not load the motor, torque does.

You won't believe me, believe Newton.

I often think that some folks I encounter on forums who do not have a scientific background are unable to read and comprehend a graph. I mean no disrespect, but can you,? Do you understand those cogging torque vs position graphs?
bi

[Turion]

If somehow magnetic attraction at TDC could be eliminated without disturbing magnetic attraction at all other rotor positions, cogging would remain unchanged.

But that magnetic attraction ISN'T eliminated, is it? And the attraction at TDC is what causes the cogging at all other rotor positions. In other words. The attraction of the rotor magnet to the core at TDC causes cogging. Just as I have said.

You must look like a freaking pretzel as much as you twist things around so as not to appear like you are wrong. And how about my “moment in time when coil and core align and magnetic attraction is the greatest” which you made fun of me for. The expert said THAT is true also and you continue to ignore it even though this is the FOURTH time in the last couple days I have reminded you. You were wrong about that. Just like you were wrong about the linear increase. Are these LIES? Just like you LIED about building the 7th grade science experiment?

Cogging torque at TDC is zero.

So what? I never said it wasn't. This is like the tenth time you have made this statement. Do you expect my response to change? But because the attraction exists at THAT SPECIFIC position, what happens when you try to move the rotor even the slightest bit? You MUST exert torque to overcome cogging. YES or NO? Yea, we ALL know the answer is yes. Hurt's doesn't it?

You claim there is a load on the motor resulting from magnetic attraction at TDC. A load on the motor must come from torque on the rotor.

I never said otherwise. Torque on the rotor, caused by the motor to moving the rotor magnet from the position of greatest magnetic attraction. So all of this is CAUSED by the attraction of the magnet to the core, just as I have said.

Torque on the rotor from magnetic attraction is cogging. Follow the logic.

Excuse me. There IS NO "torque on the rotor" from magnetic attraction. Magnetic attraction is Axial. How many times do I have to tell you that! The torque on the rotor comes from the prime mover attempting to MOVE the rotor to a position where the magnet no longer aligns with the core. That magnetic attraction REQUIRES torque to mitigate. It does not CREATE torque. Haven't I taught you anything? The MOTOR creates the torque, not the magnets.

You say "moment in time when they align and magnetic attraction is the greatest".
So what?

So what? YOU said that "moment in time" does not exist. WRONG! Even your experts say it does.

At that moment the cogging torque is zero and the greatest magnetic attraction is strictly an axial force which has been offset by Newton's equal and opposite force. Also, although academic, axial force does not load the motor, torque does.

Moving the rotor from the TDC position requires torque and loads the motor. GLAD WE AGREE. That's what I have been saying all along.

You won't believe me, believe Newton.

I have no issues with Newton. Obviously YOU do from what you said above about torque on the rotor being caused by magnetic attraction.

There's a magnetic attraction of the magnet to the core that is strongest at TDC. TRUE
In order to move the rotor from this position, torque must be applied. TRUE
This torque is applied by the prime mover. TRUE
Applying this torque results in a cost in watts of power. TRUE
That is what I have said all along.

I often think that some folks I encounter on forums who do not have a scientific background are unable to read and comprehend a graph. I mean no disrespect, but can you,? Do you understand those cogging torque vs position graphs?

Sure do. I have no problem with the graphs. They contradict what I have said in NO WAY.

[BroMikey]

But that magnetic attraction ISN'T be eliminated,

Sure do. I have no problem with the graphs. They contradict what I have said in NO WAY.

Wow, just got in Dave and you really know how to pick a process apart piece by piece and lay them all out for the students who haven't quite thought it all thru

U-get an AAA+

[BroMikey]

Here ya go Bi even you can learn about graphing



Originally posted by bistander View Post

I often think that some folks I encounter on forums who do not have a scientific background are unable to read and comprehend a graph. I mean no disrespect, but can you,? Do you understand those cogging torque vs position graphs?

[bistander]

But that magnetic attraction ISN'T be eliminated, is it? And the attraction at TDC is what causes the cogging at all other rotor positions. In other words. The attraction of the rotor magnet to the core at TDC causes cogging. Just as I have said.

Magnetic attraction causes cogging. I used to say magnetic attraction is cogging. (It's the same difference in this, IMO). However the cogging (cogging torque) at TDC is zero. So magnetic attraction at TDC is responsible for an axial force, but not cogging. It is the magnetic attraction at all positions other than TDC which causes cogging. The graphs clearly show this. Also it is easily demonstrated. A no-load generator will come to rest a the Stable Detent Position (SDP), or TDC. That's because all other positions have a non-zero cogging torque towards the SDP (except the Unstable Detent Position where it is typically impossible for the rotor to remain in equilibrium).

You must look like a freaking pretzel as much as you twist things around so as not to appear like you are wrong. And how about my “moment in time when coil and core align and magnetic attraction is the greatest” which you made fun of me for. The expert said THAT is true also and you continue to ignore it even though this is the FOURTH time in the last couple days I have reminded you. You were wrong about that. Just like you were wrong about the linear increase. Are these LIES? Just like you LIED about building the 7th grade science experiment?

Yep, I made a slight mistake on that linear statement and corrected it within hours when I discovered it. Other lies; there are none, from me. I do not understand what this "greatest attraction at TDC" relevance is. That's why I ask "so what". You still have not explained that. Please clarify what your talking about.

So what? I never said it wasn't. This is like the tenth time you have made this statement. Do you expect my response to change?

You keep asking the same question so I continue to give you the truthful answer. You do not answer my return question of "So what? do you. What difference does it make if magnetic attraction is the greatest at TDC?

I never said otherwise. Torque on the rotor, caused by the motor to moving the rotor magnet from the position of greatest magnetic attraction. So all of this is CAUSED by the attraction of the magnet to the core, just as I have said.

...
You claim there is a load on the motor resulting from magnetic attraction at TDC. A load on the motor must come from torque on the rotor. Torque on the rotor from magnetic attraction is cogging. Follow the logic.
...

Excuse me. There IS NO "torque on the rotor" from magnetic attraction. Magnetic attraction is Axial. How many times do I have to tell you that! The torque on the rotor comes from the prime mover attempting to MOVE the rotor to a position where the magnet no longer aligns with the core. That magnetic attraction REQUIRES torque to mitigate. It does not CREATE torque. Haven't I taught you anything? The MOTOR creates the torque, not the magnets.

So you do not believe that cogging is torque, or caused by torque on the rotor, all by itself. Doesn't your generator cog without the motor even connected to it? The cogging torque comes from the magnetic attraction of the magnets to the core.

So what? YOU said that "moment in time" does not exist. WRONG! Even your experts say it does.

All moments in time exist. The moment at TDC is irrelevant. At that position at that time (moment) there is zero cogging torque and magnetic attraction results in purely axial force which doesn't affect performance. So essentially nothing happens at the moment of TDC with regards to magnetic attraction or cogging.

Moving the rotor from the TDC position requires torque and loads the motor. GLAD WE AGREE. That's what I have been saying all along.

I glad we agree. You know I've never said otherwise, except maybe the torque doesn't necessarily have to come from the prime mover.

I have no issues with Newton. Obviously YOU do from what you said above about torque on the rotor being caused by magnetic attraction.

Do you really believe cogging is not torque on the rotor? Or that the magnetic attraction between magnets and core(s) causes cogging?

There's a magnetic attraction of the magnet to the core that is strongest at TDC. TRUE

True, but the force at TDC is purely axially directed and is countered by an equal and opposite force developed by the structure of the machine and bearings which enable an air gap to exist between the magnet and core face. The result is that this "strongest " magnetic attraction has no effect on the rotor at TDC. This is plainly seen on the graphs.

In order to move the rotor from this position, torque must be applied. TRUE

Yes. Only torque moves (rotates) the rotor.

This torque is applied by the prime mover. TRUE

Maybe, although not necessarily. Our discussions and that of the cogging reference paper have been about cogging torque which is unrelated to the motor. You certainly can feel cogging turning the rotor by hand, can't you? That is torque. Your hand is applying torque to rotate the rotor from the Stable Detent Position (TDC) and cogging torque is developed from magnetic attraction causing resistance to the motion (rotation).

Applying this torque results in a cost in watts of power. TRUE
That is what I have said all along.

Maybe. It could on a partial rotation. But for complete rotations, or at constant speed (like rated RPM), the CW cogging torque is offset by the CCW cogging torque and the transients (torque) are supplied from the rotor moment of inertia. So, except for a partial rotation, no, the cogging torque does not load (come from) the motor. That is why it is irrelevant at speed. There is no cost in watts due cogging at constant speed.

Sure do. I have no problem with the graphs. They contradict what I have said in NO WAY.

OK. Good. You'll note on the cogging torque vs rotor position graph that torque is not specified as to origin. If fact it can be viewed as a static condition of the motor (in this case) alone by itself with a torque wrench and protractor. The authors likely had more sophisticated instruments, but basically that's what's needed to generate the data for the graph.
bi

[Turion]

When all of this started way back when, I said that the attraction of the rotor magnet to the coil core as it approached was equal to the attraction of the coil core to the rotor magnet as the magnet moved away but that there was a moment in time when the two were perfectly aligned. A moment of MAXIMUM attraction. It requires motor TORQUE to move the magnet from this position. That is cogging. So The magnetic attraction at that point in time is responsible for or CAUSES cogging exactly as I have said.

You said that position did not exist. That was incorrect. False, Untrue. A lie.

Point 1. There is no such thing as “cogging torque.” Cogging doesn’t cause torque. Cogging is caused because of the attraction of the magnet to the core of the coil. That attraction exists whether you like it or not. Spin the rotor by hand and you will see it. Without a motor in place (or your hand. And I have to say quibbling that your hand can do the same thing as a motor is rather juvenile of you) the ONLY force present is the attraction of every single coil core to every single rotor magnet. It is an axial attraction and exists when there is no movement of the rotor AT ALL. Cogging ONLY occurs when you use TORQUE to move the magnet from that position of alignment.

Point 2. In order to spin the rotor you must PROVIDE torque to overcome, among other things, that magnetic attraction. Either spin it by hand or use a motor. Providing the torque to get the motor up to speed costs you amps and voltage to the motor measured in watts of power. Torque is less at operating speed, but you must still provide it.

Point 3. And I believe HERE is where our major disagreement lies. My contention is that a rotor spinning AT SPEED with no coils in place draws far fewer watts of power and requires less torque than does a motor spinning a rotor with 12 coils in place. And I contend that magnetic neutralization reduces the needed power and needed torque significantly. I have seen it on my big machine and I posted a video of the machine running at speed and adding a couple coils. It drew more amps and slowed the motor. I provided the 7th grade science experiment and a more recent video to show that it is true. So YOU could see for yourself. You lied about doing the 7th grade science experiment and said YOUR experiment was better.

You can quote all the textbooks and charts and graphs you want. I will go with what I see on the bench and my volt and amp meters show me. I have gotten my machine up to speed, added coils and watched it slow down and amp draw go up. Then I have implemented magnetic neutralization and watched it speed back up and the voltage and amp draw go DOWN.

What have you shown us? Charts and graphs and words. Do the experiment and prove I am wrong on the bench or please just shut up.

Edit: And by the way, I am NOT the one who developed this idea of offsetting magnets for generator coils! A patent was issued for this a LONG time ago and I have shown that patent in the past. It works. Period.