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CPC magnets: How do they work?

 
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cmjohnson



Joined: 03 Apr 2006
Posts: 5180
Location: Buried under G90s

Posted: Sat Jun 05, 2010 1:01 am    Post subject: CPC magnets: How do they work?

I've obtained a magnetic field viewer sheet for the purpose of investigating the magnetization patterns of CPC magnet
packs, as I am at least theoretically able to take a couple of CPC sets that don't have 2, 4, and 6 pole rings and combine the two sets into sets that DO have all three ring sets.

To do this, it is necessary to take a "blank" set of rings or a surplus set and demagnetize them and then remagnetize
them in the appropriate pattern.


But what is that pattern?


Well, the magnetic viewer film reveals the answer.





The top set of patterns is from the 4 pole Astig ring set.

The middle patterns: The 6 pole Triangularity rings.

The lower patterns are the 2 pole Flare set.



These are from a very clean set of CPC rings that have clear, strong magnetic patterns that will do their intended job
efficiently.

I've found that some ring sets are not as clear or as strong in their magnetization patterns as they should be. Perhaps
they've been knocked around or been too near a strong magnet that weakened them.

(You use a very strong magnet to magnetize the rings, incidentally. Small rare earth magnets arranged in the right
patter can be used to magnetize the rings as desired.)



One question that should come up is "how can I tell if my CPC rings are any good?" and I have a simple answer for you.


I have taken apart several sets, both effective ones that always worked right and also others that didn't seem to do
as good a job, and what I have observed is that a GOOD set will ALWAYS have rings in them that are strong enough
to pick up their matching ring.

To find out, carefully disassemble the whole CPC set. Isolate the ring pairs (they have gear teeth around their
perimeter, so there is no doubt what's a ring and what's just a plastic spacer) and any given ring will be able to
magnetically pick its partner up off the table if you bring the two into contact. If the ring does not have enough
strength to pick up its partner ring, then it IS bad and likely does not work very well.


In the NEAR future I will be able to provide a CPC ring optimizing service. I can read the patterns of your rings
and test them for field strength, and if they are not clear and strong, I will be able to MAKE them clear and strong,
and if you provide enough rings (with the adjuster knobs) then I can convert sets to full sets with 2, 4, and 6 pole
sets. This is probably most easily done by combine a 2 and 4 pole CPC set with a flare only set.



Of course I'll let you know when I'm ready to start up on this.


I've also acquired what I need to start rewinding Frankenyoke coils to optimal values. But I can't yet readjust
the magnetics to optimal strength values. That's coming soon.


CJ
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Nashou66



Joined: 12 Jan 2007
Posts: 16171
Location: West Seneca NY

Posted: Sat Jun 05, 2010 1:23 am    Post subject:

Cool!!

Nashou

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cmjohnson



Joined: 03 Apr 2006
Posts: 5180
Location: Buried under G90s

Posted: Sat Jun 05, 2010 3:42 am    Post subject:

One thing I've already learned is that the material the CPC rings are made out of will accept a highly "detailed" magnetic print,
fine enough that the individual gear teeth pressed into the material will print on this magnetic viewer sheet.

I've also learned that it's likely that the only practical way for me to generate correct magnetic patterns on the CPC rings is to
(A) obtain a bulk tape eraser to totally demagnetize the rings (I used one before but borrowed it, and now I know I should have
bought it when I had the chance) and (B), get into my little machine shop and fabricate a clamshell fixture that will hold six pairs
of solenoid coils and the CPC ring pairs, and use capacitive discharge through the coils to magnetize the rings properly. I'll have
to make two fixtures, though, if not three. Fortunately, I can do that. I'll get to us my rotary table on my milling machine to
do this. I'll enjoy that, except for the actual moving of it to the mill table as it's an 18" cast iron rotary table that is an easy 200 pounds,
probably closer to 300.



My problem isn't a lack of ideas. It's a lack of enough TIME to do everything I want to do at once!


CJ
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