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MKJD Question

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Fri May 16, 2008 6:36 pm PostPost subject: MKJD Question
korkskrew
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I just want to make sure I'm not taking a little walk in the weeds here.

True or False? The MKJD's will not produce a constant "negative" torque. Instead, the counter-torque is a function of the rate of change in flux and will therefore be sinusoidal with peaks occurring when the pole is pointed at the damper, and minimums occur when the poles are equidistant from the damper.

If that is true, as I think it is, the MKJD's are exhibiting their maximum effect at the same time the rotor is passing the stator.

Another true or false: The MKJD cannot produce a "positive" torque.

I am operating under the assumption that both statements are true. Sound right?
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Fri May 16, 2008 6:59 pm PostPost subject:
alsetalokin
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Sounds right to me. Additionally, the drag of the dampers is related to the stator speed. Slow rotation==little max drag. Fast rotation==correspondingly more max drag.
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Fri May 16, 2008 7:46 pm PostPost subject:
korkskrew
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alsetalokin wrote:
Sounds right to me. Additionally, the drag of the dampers is related to the stator speed. Slow rotation==little max drag. Fast rotation==correspondingly more max drag.

Thanks.

That's presumably why the speed stabilizes.

I'm trying to form an idea of why you are getting stable system behavior. This thing is about as non-linear as it gets, but you seem to get pretty linear behavior out of yours.

I know you're sick of experiment suggestions Al, but it would be awfully interesting to re-do the strobe experiment with the rotor loaded so it was only going about 400 - 500 RMP. It would be pretty revealing to know if the behavior becomes gradually more chaotic as the rotor slows or suddenly chaotic as the system changes state.

You would be able to tell because linear behavior would look like smooth motion (as shown in the strobe video) and chaotic behavior would look jittery or like it was rocking back and forth slightly.
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Fri May 16, 2008 9:24 pm PostPost subject:
alsetalokin
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Maybe it will work. I don't think so, though. Always in the past when I have loaded the rotor more than a little bit (the propeller works nicely) the stator drops out. Probably associated with the chaos you mention.
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Fri May 16, 2008 9:31 pm PostPost subject:
lostcauses
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"You would be able to tell because linear behavior would look like smooth motion"

The "would look jittery or like it was rocking back and forth slightly." shows on the stator in relation to torque and bearing slop in the new high speed video. Not so chaotic!
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Fri May 16, 2008 9:59 pm PostPost subject:
alsetalokin
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Almost 200 downloads of the 83 Mb "lips" video.

Virtue is its own reward, I guess.
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Fri May 16, 2008 10:11 pm PostPost subject:
alsetalokin
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RE chaos: I noticed in the ball-in-a-bowl videos on YT, the ball followed a chaotic, or specifically a strange attractor path, when it was doing its reversing-direction thing. Synchronistically, Grimer was accusing me of being AlSetalokin the Canadian fractal artist, and I myself was experimenting with a program called Chaoscope. I was able to generate some Julia set strange attractors that, when represented graphically, strongly resembled the chaotic path of the ball in those videos.
And now we find the stator magnet going thru similar chaotic gyrations around the time of AGW de-synch.
Presumably the same sort of thing happens on AGW start-up, as the stator synchs with the rotor.
Here's a question I haven't seen asked yet: Using my normal starting method, spinning the rotor up by hand to around 300 rpm, then, as it slows down, flipping the stator AGW: the rotor is slowing, but does the stator "catch" the rotor as the stator is speeding up from the flip, or as it is slowing down thru the synch speed? And does this have anything to do with the phenomenon of interest?
Capturing that exact moment on the MS70K will require quite a bit of finesse. And another day in the lab. Maybe I'll try again Sunday.

Am I being sufficiently turbid? (turgid?) Limpid? (Languid?)
I mean, like, does anybody really know what I mean?
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Fri May 16, 2008 10:21 pm PostPost subject:
MADPROF
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alsetalokin wrote:


RE chaos: I noticed in the ball-in-a-bowl videos on YT, the ball followed a chaotic, or specifically a strange attractor path, when it was doing its reversing-direction thing.


Ball-in-a-bowl Wink Wink
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Fri May 16, 2008 11:32 pm PostPost subject:
korkskrew
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Non-linear dynamical systems, chaos theory, etc. have long been kind of a hobby-o-mine. I immediately recognized the AGW phenomenon as an extremely non-linear situation a long time ago and have been mystified by itís stability. As fragile as it is, itís a lot more stable in real life, for nearly every replicator, than it is in my model. My model makes sense to me. I just donít get why itís so easy in real life.

As to your ponderings, I would be very surprised if the answer wasnít that the synch event occurs as the stator slows to the rate of the rotor. I always see it as throwing a basket ball into a basket. Itís a lot easier to drop it in from above, than to fling it up through the hoop. Possible but not likely.

I think it has something to do with the ďphenomenon of interestĒ only in that, being an extremely non-linear system, very tiny variations can have a significant impact on the ďlocationĒ (in phase space) of the steady state. I have been exploring this just recently in my torque tables but have been thwarted by my inability to figure out where the PE well is.

The AGW phase relationship is pretty well known by now. But I canít figure out why that is the stable (or metastable) phase relationship. Any way I analyze it it looks like that phase relationship is either on a PE peak or a PE slope. Definitely not a PE well. But it HAS to be a well, and Iím just not looking at it right. Once I find out how to see the PE well, I can start looking at how small changes can effect that well. Then Iíll really have something to start posting about.
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Fri May 16, 2008 11:42 pm PostPost subject:
korkskrew
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alsetalokin wrote:
Maybe it will work. I don't think so, though. Always in the past when I have loaded the rotor more than a little bit (the propeller works nicely) the stator drops out. Probably associated with the chaos you mention.

Have you thought of using a coil with a potentiometer across it? It would act almost like a speed govenor. I would put it on the opposite side of the rotor from where the AGW stator is, just so it doesnít mess with the stator.

*edit* It would make surplus energy measurements a snap too.
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Fri May 16, 2008 11:59 pm PostPost subject:
korkskrew
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lostcauses wrote:
"You would be able to tell because linear behavior would look like smooth motion"

The "would look jittery or like it was rocking back and forth slightly." shows on the stator in relation to torque and bearing slop in the new high speed video. Not so chaotic!


I haven't been able to obtain the viewer yet, so analysis will take me some time. Confused
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Sat May 17, 2008 12:04 am PostPost subject:
overconfident
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korkskrew wrote:

Non-linear dynamical systems, chaos theory, etc. have long been kind of a hobby-o-mine. I immediately recognized the AGW phenomenon as an extremely non-linear situation a long time ago and have been mystified by itís stability. As fragile as it is, itís a lot more stable in real life, for nearly every replicator, than it is in my model. My model makes sense to me. I just donít get why itís so easy in real life.


I also don't know why it's so easy. I'm not going by any fancy theories or math, just the amorphous images in my head. Here's what I told Al when he first mentioned AGW to me. I thought he was just fantasizing at the time:
http://www.steorn.com/forum/comments.php?DiscussionID=59687&page=5#Item_43
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Sat May 17, 2008 12:24 am PostPost subject:
alsetalokin
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Korkskrew I'm sorry, I somehow skippped you on the distribution. Check your pm's for the url and pwd.
(After korkskrew downloads the viewer I will be removing it, because I figure everyone who really needs it has gotten it by now. MediaPlayerClassic or mplayer will work well enough for everybody except the most, well, anal-ytical of us.)
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Sat May 17, 2008 12:32 am PostPost subject:
lostcauses
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Windows media player will play them and you can see the vibration of the magnetic torque by looking at the center. There may be other AVI players out their that can do frame by frame.
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Thu May 22, 2008 11:41 am PostPost subject:
billgates
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A nice freeware AVI editor (and player) is VirtualDub (http://virtualdub.sourceforge.net/)

It lets you view any movie frame-by-frame, it includes many filters and many others can be added (also input filters for MOV, VOB, MPG, WMV etc)... Wink
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Thu May 22, 2008 3:03 pm PostPost subject:
overconfident
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billgates wrote:
A nice freeware AVI editor (and player) is VirtualDub (http://virtualdub.sourceforge.net/)

It lets you view any movie frame-by-frame, it includes many filters and many others can be added (also input filters for MOV, VOB, MPG, WMV etc)... :wink:


Does it do .amv videos?
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Thu May 22, 2008 8:03 pm PostPost subject:
billgates
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[quote="overconfident"]
billgates wrote:
Does it do .amv videos?


No, Crying or Very sad you have to convert AMV into AVI before using them with VirtualDub.
You can find a nice converter at http://code.google.com/p/amv-codec-tools/downloads/list

The direct link to download the Windows version is:
http://amv-codec-tools.googlecode.com/files/amv-ffmpeg-win32-20071029.zip

After unzipping it, just put your AMV video (i.e. example.amv) in the "amv-ffmpeg-win32-20071029\local\bin" folder, then open a command shell, move to that folder ("cd c:\.....\local\bin") and type:

ffmpeg -i example.amv example.avi

et voilŗ. You converted your amv to an avi video. Pretty simple!
Surprised
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