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Old Jan 27, 2012, 10:13 PM
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Stator insulation & Epoxy

Hi all, I'm about to rewind a 4035 scorpion motor, maybee some other if things goes well.

I need to find a good way to insulate the stator but after several hours reading and googleing I don't find much info about that.

The easiest thing to buy for me will be kapton, is this good..? Some suggestion will be appreciated.

Next thing I need is good epoxy to put on the wiring once it's done, but cannot seems to find where to buy it, or what exactly to buy.

I emailed scorpion to buy their stuff, but got an automated email saying '' due to chinese new years, we are close...... blablabla.....''
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Old Jan 28, 2012, 06:49 AM
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http://www.powerditto.de/statorisolieren.html
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Old Jan 28, 2012, 10:09 AM
Jack
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Joined May 2008
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The link that scorpion-fan posted can be translated with google:

http://tinyurl.com/76n9hsz

And there has been a lot of discussion here on using a lot of different materials and coatings for re-insulating stators or repairing damaged stator coatings. An Advanced Search of this forum, with a date range of Any Date will get you a lot of ideas.

I don't think one single best product or method has emerged here, I wish I could find a way to put a coating on that is like the standard green coating that most of the stators have on arrival from China. , I just don't know how they do that or what is used to do that.

Jack
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Old Jan 28, 2012, 11:24 AM
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What Jack said about the coating. I've tried JB Weld thinned slightly with a little denatured alcohol, nail polish, and I've read of folks using exhaust manifold spray paint.

IMO you don't want to epoxy your wires once they are on. The wires on a properly wound motor aren't going anywhere.
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Old Jan 28, 2012, 08:57 PM
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United States, MI, Ann Arbor
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Quote:
Originally Posted by martin_ View Post
Hi all, I'm about to rewind a 4035 scorpion motor, maybee some other if things goes well.

I need to find a good way to insulate the stator but after several hours reading and googleing I don't find much info about that.

The easiest thing to buy for me will be kapton, is this good..? Some suggestion will be appreciated.

Next thing I need is good epoxy to put on the wiring once it's done, but cannot seems to find where to buy it, or what exactly to buy.

I emailed scorpion to buy their stuff, but got an automated email saying '' due to chinese new years, we are close...... blablabla.....''
http://www.rcgroups.com/forums/showthread.php?t=1562825

I have used 0.125mm kapton for insulation between wires and stator, after sandering the sharp edges of the stator a bit. It works well. 0.1mm kapton also recommamded by Powercroco's website. I have tried 0.15mm kapton on one of my scorpion 40XX, it also works pretty well in terms of insulation, but it is comparatively harder to bend than the 0.125mm kapton.

Kapton I use is rated 180 degree C. It is a good and eazy way of achieving the insulation during rewinding, in my opinion.
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Old Jan 29, 2012, 09:20 AM
Jack
USA, ME, Ellsworth
Joined May 2008
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I bought some Kapton sheets on eBay a while back but have not tried them out yet, there are thousands of Kapton sellers there, here is the stuff I bought:

http://www.ebay.com/itm/380299762250

That was for three sheets with the thickness (0.002"/0.050mm), I asked the seller to substitute a thinner sheet for one of the three and he did that for me. Nice guy!

Jack
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Old Jan 29, 2012, 09:25 PM
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Ok, thanks guy, I finally bought Kapton from Ebay and high temp Epoxy kit, also 22, 20, 18, 16, 14awg magnet wire.

I took KV reading on my motor today on the press drill, I'm surprised that it exactly match the 500kv rating, the drill method is accurate, then I took appart the motor and removed the existing wire.

There was not much epoxy on the winding, very easy to do and the factory insulation sheet are still on the stator and in very good condition as well as the top and bottom insulation part.

My goal is to lower the KV at 350 to use on a 800 ship for 16s lipo, in YY configuration, I find 9+9 turn give me 346kv.

Now I'm ready to rewind, just have to wait for my ebay stock to get here.

Will let you know how it goes.
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Old Jan 31, 2012, 01:03 PM
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when you tear off the original wires of your scorpion, you may have noticed that there are crossing-over turns, which may have affected its Kv. My experiences is that a true "6 turns delta" winding (no crossing over turns of wires) of a scorpion 4035 (12N8P version), will give 10XX Kv (my rewinded Kv is 1073), while the original "6 turns delta" 4035 12N8P scorpion is rated 800Kv.

I have also done three 4025 rewinding job, my results also shows about 150-250 more on Kv number than the original winding, rewinded with "same" number of turns.

to note that "6 turns delta" means 6 turns of wires in each slot, 3 wires terminated as delta.
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Old Jan 31, 2012, 07:15 PM
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Yes, it have 5.5 turn, I found it strange.

For now I rewind it in parallel and use ''YY'', which is different than the original delta terminating.

http://translate.googleusercontent.c...1M8H-6u4WKZj0A

Out of curiosity, have you measured your KV with a drill press, multimeter and tach?
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Old Feb 01, 2012, 01:42 AM
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Quote:
Originally Posted by martin_ View Post
Yes, it have 5.5 turn, I found it strange.

For now I rewind it in parallel and use ''YY'', which is different than the original delta terminating.

http://translate.googleusercontent.c...1M8H-6u4WKZj0A

Out of curiosity, have you measured your KV with a drill press, multimeter and tach?
I use another way to measure the Kv, which is accurate enough for me. I test my original scorpion's Kv with this acoustic method, and it is a good match with the labelled Kv. You can try it if you are interested. Here is a thread I posted: http://www.rcgroups.com/forums/showthread.php?t=1559695

So your's 4035 is the newer HKIII 12N10P. It will be nice to try the YYwinding, which will make single thick wire winding much easier. Good luck.

When I disassemble my 4035 and replaced with a new shaft, it seems that I may have broke the balance of the bell, as i noticed some vibrations when the reassembled motor (rewinded) is tested to about 25,000 rpm speed. Be careful.
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Old Feb 01, 2012, 09:25 AM
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Ya, I had seen your post about the accoustic test.

In fact my motor is an Hyperion 4035-500 12n10p, same as the HKIII.

I have the SK-720 with vibration logger, I will make a quick test running the motor only to see if vib have increased, I changed the main shaft too for a longer one.
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Old Feb 01, 2012, 01:26 PM
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Originally Posted by martin_ View Post
Ya, I had seen your post about the accoustic test.

In fact my motor is an Hyperion 4035-500 12n10p, same as the HKIII.

I have the SK-720 with vibration logger, I will make a quick test running the motor only to see if vib have increased, I changed the main shaft too for a longer one.
I see, hyperion motor is nearly identical to scorpion ^^. My original scorpion 40xx, both 4035 and 3 4025, all have perfect test run with no vibration felt with bare hand. I rewinded all except one of the 4035, and only the 4035 gives greater vibration during the test run after a rewind and shaft , bearing replacement. So i must have screwed up something, and i am still trying to figure out the problem. Also i am having a hard time to rebalance the 4035

Does the SK-720 help to rebalance the bell (to determine where to add or cut weight on the bell) or it can only be used to test vibration level?
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Old Feb 01, 2012, 06:03 PM
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SK-720 will only tell you where are the vibration on the heli, and how much of it.

Basically, everything vibrate on an heli, but must be in a respectable range.
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Old Feb 06, 2012, 10:38 PM
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The best thing I have found to use is thinned JB Weld with acetone. I rewound four motors a few days that were originally bare metal that I painted with thinned JB Weld. With tight winds, none of the phases had continuity to the motor. I thin it down so it is about as thick as paint, and paint it on. In some cases I have gone back with a second coat that was slightly thicker and added a second coat at the ends where the wire wraps around and is most likely to lose some of its insulation when pulled tight. I just painted another stator tonight with JB Weld.

The photo of two motors shows what I did a few nights ago. The motor on the left was done in a single coat. The one on the right required an extra dab in a couple places where the JB Weld was not quite thick enough at a few corners.

The other photos show the one I am working on tonight.

I have tried paint on insulation, but it rubs off too easily.

Chris
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Old Feb 06, 2012, 11:09 PM
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I use denatured alcohol since that is what most folks use for epoxy. It seems to work OK.
Have you tried that vs acetone?
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