The bistander thread

[bistander]

That's a nice study bi. You did a good job presenting the parts of it you wanted to present to support you mistaken understanding of how my generator works. Excellent job. But now, how about we take a look at the TRUTH. Because this study completely supports EXACTLY what I have always claimed.

I NEVER SAID cogging was produced at TDC. NEVER. Find where I said that. You can't
Here is what I have said: "There is a moment in time when the rotor magnet is perfectly aligned with the coil where maximum attraction between the coil and the core exists."

Remember bi, you made FUN of my "moment in time" and insisted that the approach of the magnet to the core was equal to the magnet leaving the core. You did that on MORE than one occasion. But you were WRONG about that, and this study confirms it. I notice you have never addressed THAT little slip up on your part. You always gloss over the parts you don't like.

I stated that this attraction of the magnet to the core caused cogging, and said that while the physical action of cogging goes away at speed (or smooths out so much it is imperceptible, the magnets' attraction to the core NEVER goes away, and I refer to it as "magnetic drag."

So let's look at drawing "c" shall we?
drawing c.png

And what do the say about this position where the magnet and the coil are perfectly aligned?

"Figure 2c displays the rotor aligned in a stable detent position. Here, the air gap space and corresponding reluctance are minimized. Any displacement of the rotor from this position results in cogging torque which attempts to re-align the rotor to this position." WHICH position does the magnetic attraction attempt to align the rotor to? The one where I said the greatest magnetic attraction existed. Hmmm, guess I was correct. I NEVER said that was the position where the greatest COGGING OCCURRED which, according to this study, is position 'B". I said it CAUSED cogging. I am not an idiot. I do not believe that a stationary rotor aligned with the coil produces cogging. The rotor must MOVE AWAY or PAST the coil to produce cogging.

When this attraction is ELIMINATED, balanced, offset, compensated for...use WHATEVER term suits your fancy, there IS no NEGATIVE (causing bad results, in case you are going to try to define that differently) magnetic attraction that does not have a NEUTRALIZING repulsion and ALL magnetic attraction of ALL magnets to ALL cores that cause magnetic drag are not ELIMINATED, but simply balanced and NEUTRALIZED. Free spinning rotor.

Thanks for the info. I have been looking for something that supported my position, and this does it quite nicely.

Simply put, look at it this way. If that moment of greatest attraction did NOT exist, would cogging exist? The Defense rests.

There is attraction at TDC, Stable Detent Position, point c on the diagram, but zero torque from the core magnet attraction, just an axial force.

How can you believe an axial force produces torque? Ever used a lazy Susan? Or a swivel bar stool? The weight placed on the platter causes an axial force downward due to gravity. It does not cause a torque on the platter. Look at this video.
https://youtu.be/kNU370c42mw
There are some heavy items on those swivel platforms and obviously zero torque resulting from the axial force downward and very little torque needed to rotate slowly, just enough to overcome a small friction component and required to accelerate the moment of inertia. The worker appears to rotate hundreds of pounds of axial force with the slight torque applied by a near effortless hand motion. Axial force causes no torque by which the motor is loaded from your generator.

And you mentioned the cogging "jerk" before being caused by the axial force. That's wrong. The jerk is a torque, or circumferential disturbance as the rotor passes through the Stable Detent Position going from CW torque to CCW torque. This is clearly visible on the graph in the article and graph which I posted last week.

And you never did explain your disagreement with Newton about equal and opposite forces. How does a physical air gap exist between the magnet and core face in your generator without that equal and opposite force acting on the magnet and core to offset the attractive axial force? It can not. The presence of the gap proves there is an opposing force already there. Your opposition magnet is superfluous in counteracting axial force of attraction between the magnet and core.

You say:
"Simply put, look at it this way. If that moment of greatest attraction did NOT exist, would cogging exist? The Defense rests."

Sure. It already happens. "that moment of greatest attraction" is zero on the cogging graph. It is already exactly, precisely offset by Newton's equal and opposite force, so in essence, it doesn't exist. Only the circumferential forces (torques).
From the article

Cogging torque is produced, in a brushless PM machine, by the magnetic attraction between the rotor
mounted permanent magnets and the stator teeth. It is the circumferential component of attractive force
that attempts to maintain the alignment between the stator teeth and the permanent magnets.

Note the underlined. The axial force isn't mentioned, just the circumferential component.
bi

[BroMikey]

I read your reply Dave and even tho I try not to look like I am stroking your person I just can't help giving honor to your ability to write, reason and keep everyone on track. You amaze me. I guess those masters degrees paid off. I'll bet the underdog is seething complete with brain fog even tho you only meant to correct the wrongs in the so called page of higher learning. But some people take everything personal no matter what you do.

A rich man is to arrogant to receive a free will offering because he would feel like a poor beggar if he did. Can't have that.

[Turion]

That's a nice study bi. You did a good job presenting the parts of it you wanted to present to support you mistaken understanding of how my generator works. Excellent job. But now, how about we take a look at the TRUTH. Because this study completely supports EXACTLY what I have always claimed.

I NEVER SAID cogging was produced at TDC. NEVER. Find where I said that. You can't
Here is what I have said: "There is a moment in time when the rotor magnet is perfectly aligned with the coil where maximum attraction between the coil and the core exists."

Remember bi, you made FUN of my "moment in time" and insisted that the approach of the magnet to the core was equal to the magnet leaving the core. You did that on MORE than one occasion. But you were WRONG about that, and this study confirms it. I notice you have never addressed THAT little slip up on your part. You always gloss over the parts you don't like.

I stated that this attraction of the magnet to the core caused cogging, and said that while the physical action of cogging goes away at speed (or smooths out so much it is imperceptible, the magnets' attraction to the core NEVER goes away, and I refer to it as "magnetic drag."

So let's look at drawing "c" shall we?
drawing c.png

And what do the say about this position where the magnet and the coil are perfectly aligned?

"Figure 2c displays the rotor aligned in a stable detent position. Here, the air gap space and corresponding reluctance are minimized. Any displacement of the rotor from this position results in cogging torque which attempts to re-align the rotor to this position." WHICH position does the magnetic attraction attempt to align the rotor to? The one where I said the greatest magnetic attraction existed. Hmmm, guess I was correct. I NEVER said that was the position where the greatest COGGING OCCURRED which, according to this study, is position 'B". I said it CAUSED cogging. I am not an idiot. I do not believe that a stationary rotor aligned with the coil produces cogging. The rotor magnet must MOVE AWAY or PAST the coil core to produce cogging.

When this attraction is ELIMINATED, balanced, offset, compensated for...use WHATEVER term suits your fancy, there IS no NEGATIVE (causing bad results, in case you are going to try to define that differently) magnetic attraction that does not have a NEUTRALIZING repulsion and ALL magnetic attraction of ALL magnets to ALL cores that cause magnetic drag are not ELIMINATED, but simply balanced and NEUTRALIZED. Free spinning rotor.

Thanks for the info. I have been looking for something that supported my position, and this does it quite nicely.

Simply put, look at it this way. If that moment of greatest attraction did NOT exist, would cogging exist? The Defense rests.

[BroMikey]

COGGING

Hello Turion and all,
a technical understandable definition of cogging in Permanent Magnet Synchronous Machines (PMSM). I have found such.

Dave had surgery on his hand which they re-break and set and had to go to 2 Dr offices today. Probably hurts like hell and needs more rest. Don't just assume he won't be back to shoot holes in your papers

[BroMikey]

COGGING

Hello Turion and all,
They say "no net cogging torque is produced" at TDC.
bi

THEY also say negative work is nothing of any concern in an electric motor. These are university parrots who do not know any better, besides lumping all motors in to one viewpoint has it's inaccuracies.

With what we have shown everyone they should know better than that.

[BroMikey]

You mean this link? "A stable catch position"

https://www2.ece.ohio-state.edu/ems/...20Machines.pdf

[bistander]

COGGING

Hello Turion and all,

I have been on the lookout for a authoritative paper, text or presentation giving a technical understandable definition of cogging in Permanent Magnet Synchronous Machines (PMSM). I have found such. I will supply the link. But first:

Turion has recently again expressed his contention that cogging includes or is caused by the axial force of attraction between magnet and core at TDC (Top Dead Center), a position the paper calls Stable Detent Position. Here is a copy of that section:

Cogging torque is produced, in a brushless PM machine, by the magnetic attraction between the rotor
mounted permanent magnets and the stator teeth. It is the circumferential component of attractive force
that attempts to maintain the alignment between the stator teeth and the permanent magnets.

Figure 1 displays two positions of a permanent magnet in relation to three stator teeth. The permanent
magnet in figure 1 represents a single pole of a multi-pole machine. In figure 1a, the permanent magnet is
aligned with the maximum amount of stator teeth. In this position, the circumferential components of
force produced by the magnetic flux entering the stator teeth cancel. Thus, no net cogging torque is produced.

quote from:

Study of Cogging Torque in Permanent Magnet Machines
C. Studer, Student Member A. Keyhani, SM
Department of Electrical Engineering
The Ohio State University
Columbus, OH 43210
&
T. Sebastian, Member S. K. Murthy, Member
Saginaw Steering Systems
Delphi
Saginaw, MI 48601

https://www2.ece.ohio-state.edu/ems/...20Machines.pdf

The quoted section with diagrams are right at the beginning of the document.

Turion, these authors fully confirm what I've been telling you about cogging and axial force. A few of the terms are different like circumferential where I used tangential, and Stable Detent Position vs TDC, but the meaning is clear. They say "no net cogging torque is produced" at TDC.
bi
Screenshot_20220206-152756-513.png

[BroMikey]

This gentlemen helps the beginner look at eff. See chart near the end. 23% and up for electric motors driving electric generators

[BroMikey]

Sorry, this is unacceptable

Please leave my definition as is ....

....please don't rule out mine
bi

Let me get this straight, Bi is now sniveling, begging prostate? You scared bro?

Bi you need to do this first and report back on COP, then you will see our success
COP here is 30% or maybe 40%

https://www.youtube.com/watch?v=cJ_vDA7xsGs

[Turion]

Sorry, this is unacceptable because it includes the premise that "attraction, of the magnet to the core at TDC, resulting in extra loading of the prime mover (motor)" . You know that I disagree with that. Please leave my definition as is because I don't rule out your contention, please don't rule out mine. Let the truth come out on the bench.
bi

Or if you insist,



Added "theorized to be" and "possibly" in red. Changed "eliminates" to "may eliminate" in red.

That's fine. What I wrote is a statement of what I believe to be facts. You have changed it to a statement of theories to be proven or disproven. Fine with me. I believe I HAVE proven them. You believe I have not and cannot. On that I'm sure we agree.

[BroMikey]

. Does that increase motor input power? I say no. You say yes. Let's find out in a scientific way.
bi

That is why you have a setup of your own of anything, you tell me. So you are saying that your rig goes up? or down? show us and cut the chatter

https://www.youtube.com/watch?v=AZeWPlVoLko

[bistander]

I have no idea why it is "so important" to clarify these points. These are the same claims I have made all along. The same way I have described magnetic neutralization and what it does in the machine. I THINK I know where you are going with all this, but it will be interesting to wait and see what happens. Trying to give me enough rope to hang myself? LOL.

I am trying to fashion a statement of exactly what to verify and then best way to do that. Obviously the best way is to have your actual device up and running totally tuned by you, in equilibrium with instruments showing in real time and simply back out the equalization magnets. Does that increase motor input power? I say no. You say yes. Let's find out in a scientific way.
bi

[bistander]

You want simple. Here is simple:
Magnetic drag is the attraction, or caused by the attraction, of the magnet to the core at TDC, resulting in extra loading of the prime mover (motor) and magnetic neutralization eliminates this or SIGNIFICANTLY reduces it.

From bi:
When we were discussing the 7th grade experiment, your generator design used all N facing magnets on the rotor, 22 of them. No additional "neutralization" magnets were required on the rotor, just on the stator. Target was 2800 RPM (constant) for generation of your target 1800-2000W real power output.

I agree with that. (1800-2,000W is what I hoped for)

Again, I have NO IDEA what the machine with 22 N magnets would do, or if it would even work. It was a prototype I built to test whether I could use HALF the magnets I used on the big clunker machine and build something more compact. I KNEW there was a GOOD chance it would not put out the power the old clunker produced because it contained two FEWER coils; 10 rather than 12. I have no illusion that 10 coils can suddenly put out the same power as 12 just because I WANT them to. My HOPE was that 22 rotor magnets instead of 12 would make up for the missing coils. So yes, the target was 1800-2000 watts, because I know that is possible with the big machine. I always have HOPE. Reality is what I see when it runs on the bench.

You want simple. Here is simple:
Magnetic drag is theorized to be the attraction, or caused by the attraction, of the magnet to the core at TDC, possibly resulting in extra loading of the prime mover (motor) and magnetic neutralization eliminates this or SIGNIFICANTLY reduces it.

Sorry, this is unacceptable because it includes the premise that "attraction, of the magnet to the core at TDC, resulting in extra loading of the prime mover (motor)" . You know that I disagree with that. Please leave my definition as is because I don't rule out your contention, please don't rule out mine. Let the truth come out on the bench.
bi

Or if you insist,

You want simple. Here is simple:
Magnetic drag is theorized to be the attraction, or caused by the attraction, of the magnet to the core at TDC, possibly resulting in extra loading of the prime mover (motor) and magnetic neutralization may eliminate this or SIGNIFICANTLY reduces it.

Added "theorized to be" and "possibly" in red. Changed "eliminates" to "may eliminate" in red.

[Turion]

I have no idea why it is "so important" to clarify these points. These are the same claims I have made all along. The same way I have described magnetic neutralization and what it does in the machine. I THINK I know where you are going with all this, but it will be interesting to wait and see what happens. Trying to give me enough rope to hang myself? LOL.

[bistander]

...
I was the one who first brought up a "7th grade science experiment". The 7th grade science experiment I spoke of was the one I showed in the video I posted where I show that it works. That is an all N magnet rotor, which you MUST have to do the experiment the way I showed it. I showed the experiment that way because a setup VERY MUCH like that one is where I first saw what was possible with magnetic neutralization. I wasn't the only one. At the time I asked Carroll Brotzge (you may remember Carroll) and a few others who had tVERY SIMILAR setups on their benches (we were all working on small motors of that type) to replicate, and they all got the same results. That is when I first added magnetic neutralization to my large generator builds.
...

...
I don't necessarily agree with your definitions above, but want to establish where the state of "development" was at time I designed my version of the "7th grade experiment". Please just confirm or correct the above explanation without argument. Is it correct so far?
...

Added "version ot the".

I hope that satisfies your objection.

I realize it is different from your 7th grade experiment, but I don't know how to interpret holding something and not reading meters which have stabilized. I want something that is repeatable and can generate data which can be analyzed. Another goal of my version was to minimize variables and sources of error and uncertainty.
bi