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What Coordinate System For the WhiPMag?

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Should 0 be on the Y+? And should it increment CW?

Yes / CW
28%
 28%  [ 2 ]
No
42%
 42%  [ 3 ]
Yes / CCW
28%
 28%  [ 2 ]
Total Votes : 7


Sun May 25, 2008 11:27 pm PostPost subject: What Coordinate System For the WhiPMag?
Harvey
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It has already been agreed to lay the base in the XY plane. Using a top view and left hand rule this would give UP=Y+, RIGHT = X+, and Z+ points at the viewer. But there is Some discussion as to where 0 should be located for purposes of rotation reference of the Rotor and Stator. Also, which direction will the degrees increment?

For phase angles, 0 lies on an imaginary line running from the axle of the rotor, through the midpoint of both rotor and stator magnets to the stator axle. This is a localized reference creating a ratio between any given stator and any given rotor magnet and is independant of all other coordinates. Thus it excludes any reference from one stator to another.

Adopting an absolute coordinate will give the group a standard way of referencing what they observe.
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Sun May 25, 2008 11:58 pm PostPost subject: Re: What Coordinate System For the WhiPMag?
overconfident
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I agree with the planes and 0 degree mark, but think the numbering should progress CCW. Since Al normally spins the rotor CW, the numbers will increment as they pass by the stator.

However, if we don't write any numbers, just put hash marks, then which direction the numbers progress is a moot point.
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Mon May 26, 2008 3:19 am PostPost subject:
Gent
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Hi all, its normal in all the cad cam stuff that I am familiar with for 0 degrees to be
X+ or to the right and numbered counter clockwise from there, 90 degrees would be Y+ 180 X- 270 Y- I think this is prety standard?
BWDIK lol

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it seems a shame, the walrus said, to play them such a trick
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Mon May 26, 2008 8:06 am PostPost subject:
Axle
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I vote for this. This is how my CAD is set-up. It agrees with what Gent posted.



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Mon May 26, 2008 9:00 am PostPost subject:
Harvey
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Thanx Gent & Axle, this is congruent with Autocad as I posted in another thread. It also agrees with half of overconfidents wish in that the numbers increment CCW.

So far the No's have it. Later today I'll put up a poll for the Autocad WCS and see if any of the yes votes here are willing to adopt that as the standard. If so, then we may have what we need. Wink

EDIT to remove Tomorrow and replace with Later today.
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Mon May 26, 2008 4:54 pm PostPost subject:
Mr.Entropy
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I also suggest you set time t=0 to the moment when rotor magnet 0 is aligned along Y and adjacent to the active stator (even if the rotor magnet is shifted in its slot, so that it isn't perfectly bisected by the rotor-stator line)
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Mon May 26, 2008 10:04 pm PostPost subject:
alsetalokin
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I don't mind indexing time at zero, but please, let's index physical objects with 1==there is no "zeroeth" rotor magnet, only a first one.
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Mon May 26, 2008 10:26 pm PostPost subject:
Harvey
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@Mr. Entropy,
These are the compound angles (Euler Angles) I referred to earlier. Without going into an entirely spatial coordinate system, we could still easily indentify the possibilities using twist. This could simply be identified by the rotor magnet orientation at 0. The orientation my have twist on the vertical Z-axis and/or (as in the case of Yadaraf and ClaNZeRs recent tests) a twist on the horizontal (Y or X depending on which we adopt) axis. The twist identification would follow the same convention (CW or CCW) as the coordinate system we adopt. In this way we leave t=? flexible to be used variably especially when RPM's are changing.

If an experimenter were to slide the rotor magnet in the slot and then turn the rotor to align the magnet he would find that it is twisted on the Z-axis one way or the other depending on which way he slides it.

Thanx helping us address this.
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Tue May 27, 2008 8:54 am PostPost subject:
Harvey
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We have 153 views, 6 votes, and with this 8 posts. This may represent 10 persons viewing each post 2 or more times, or as many as 21 persons viewing each post once as they arrived. It could represent a larger number as well for persons who have viewed all 7 posts at the same time in one visit. At any rate it may show that some viewers have not participated in the poll. Perhaps this is a quantum event and Heisenbergs principle applies.

In order to see the poll results you must vote.

I have voted yes in both polls. This is because I believe some standard should be adopted and I can easily use either. Thus even where uncertainty exists, it is possible encourage one or the other by a lack of no votes.
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Fri May 30, 2008 12:41 am PostPost subject:
Harvey
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I found this point interesting at 29 minutes:

http://mfile.akamai.com/7870/rm/mitstorage.download.akamai.com/7870/8/8.01/f99/videolectures/wl99lec3-80k.rm

Cool
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Fri May 30, 2008 2:39 am PostPost subject:
lostcauses
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You mean using vector math that the graph should not end up with a negative z?

I take it that is your point is the right handed system.
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