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Copper hardware on PS4002 endbells


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#1 scaleuser

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Posted 23 May 2013 - 08:45 PM

I set up two of these replacing the stock hardware with the copper. You must open up the inside as the resulting hole is too small for the commutator.

 

I used a koford splined brush radius tool to carve the hole bigger it measures .210 dia. After removing the hoods for deburring, I was quite pleased with the precision and the fact that the brushes are supported all the way to within .005 of the comutator.

 

one of the motors with a smaller com works really well, the other seems to eat brushes and has not been as fast. the com is still at 199. I'm using the PS X12 arms in them.

 

Question: motor experts: what is a good way to open up the hole to clear the commutator? And might these brush holders be too close at 5 thou?

 

They don't seem to be getting burned by the arc blast but I've never seen any motor with them this close.

 

All opinions welcome.

 


Don Latch

 

anything worth doing is worth overdoing





#2 havlicek

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Posted 24 May 2013 - 05:28 AM

 

Question: motor experts: what is a good way to open up the hole to clear the commutator? And might these brush holders be too close at 5 thou?

 

 

I'm not an expert, but until one shows up, I'll try to help.  Anything that works is fine.  I use a diamond burr sometimes ("small flame tip") and sometimes I use a small diameter Dremel grey stone.  Either way, you must de-bur afterwards and be sure the brushes will pass freely through the hardware...if they fall through on their own, that's best as long as they aren't at all sloppy.

 

 

They don't seem to be getting burned by the arc blast but I've never seen any motor with them this close.

 

 

There's no advantage to having them that close.  It could even be that they seem to be clearing when spun by hand, but that they aren't clearing enough when the motor is spinning under it's own power.  You have nothing to lose by opening up the inside of the hardware some more.  Think about it, you will never let a pair of brushes get so small that the hardware needs to be that close to the com to keep the brushes moving straight and true.  The slots for the springs and fairly far away from the ends of the hardware anyway.  A bit more of a gap will certainly not cause you problems, and it "might" solve this.  Also, coming up with a .005" clearance number by doing the math (it can't be measured directly) is most likely a little inaccurate because it doesn't take into account any non-concentricity.

 

-john


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John Havlicek

#3 Marty N

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Posted 24 May 2013 - 07:55 AM

 

I use a radius hone that measures .207" after blueprinting the can and hardware with the bell installed. Like line honing main bearing saddles. Debur with a small set of jeweler files and a knifed clay tool without disturbing the hoods. Can and bell have to be stiff, a very snug fit and well aligned to fit hardware this tight and use of good bearings is a must as is a very straight armature. I also do a clean up cut on the commutator with even new arms. I was surprised when I first started doing this how untrue a new commutator can be so it's practice these days. Burnishing the slots of the commutator with a ball burnish without disturbing the commutator lathe or settings and a last pass in the lathe to clean up the "bump" created from the burnishing process greatly enhances brush life. A sharp edge turns the commutator into a pencil sharpener. Been do this procedure in open motor drag cars for years without issue so what I'm saying is .210" isn't an issue and your brush problem is more than likely a commutator slot preparation thing. In fact on the more flimsy white bell motors it's likely a good idea to be a bit more open in this area. They walk about a bit in the tower.

What can be an issue is removing the hoods after clearancing to debur as you will never get them in the same place twice without a fixture of some sort. Your hole will no longer be concentric. I'm just say'n.


Martin Nissen

#4 scaleuser

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Posted 27 May 2013 - 09:14 PM

Thanks John, Marty. I will open them up a bit. Couldn't hurt.

Don Latch

 

anything worth doing is worth overdoing






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