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Old Apr 07, 2011, 03:11 AM
The Flying Ottoman
Dt.Serkan's Avatar
Turkey, Trabzon, Maška
Joined Jul 2010
47 Posts
About insulating the stator with the epoxy dipping, does it matter what kind of dark paint we use?
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Old Apr 14, 2011, 03:09 PM
Engineer for Christ
IBCrazy's Avatar
Amherst, VA
Joined Jun 2006
10,296 Posts
Not really. it just needs to be thick enough to coat the end turns properly.

-Alex
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Old Apr 14, 2011, 03:11 PM
Engineer for Christ
IBCrazy's Avatar
Amherst, VA
Joined Jun 2006
10,296 Posts
Quote:
Originally Posted by Dt.Serkan View Post
So you say rewinding a dead motor is rarely efficient because of the weakened magnets? Also I realized something that I was using CA to stabilize the wire and I have just seen that you said the CA is not suitable for the wire holding. Can this be the cause?
I unwound my motor thinking the CA is the cause and will rewind again. I hope I can solve this problem.
Thank you very much Alex for your helps again.
CA glue attacks certain types of wire insulation. If you use kicker and cure it immediately, you should be ok. The real problem is that when the motor burned up, it did so because it got hot, thus overheating the magnets and irreversably damaged them.

-Alex
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Old Apr 18, 2011, 02:05 PM
The Flying Ottoman
Dt.Serkan's Avatar
Turkey, Trabzon, Maška
Joined Jul 2010
47 Posts
I rewound my motor and now it is better. I have another question about the epoxy glued wires on the stator. It is throughly an headache! I can not remove the wire espacially if the wire is thin. I found some information how to remove the glue as we can put the stator in an oven that heated about 250C for 10-15mins. Is there any easier solution of you for this situation? Thanks again.

_Serkan_
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Old Apr 21, 2011, 07:25 AM
Engineer for Christ
IBCrazy's Avatar
Amherst, VA
Joined Jun 2006
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Quote:
Originally Posted by Dt.Serkan View Post
I rewound my motor and now it is better. I have another question about the epoxy glued wires on the stator. It is throughly an headache! I can not remove the wire espacially if the wire is thin. I found some information how to remove the glue as we can put the stator in an oven that heated about 250C for 10-15mins. Is there any easier solution of you for this situation? Thanks again.

_Serkan_
Nope. I do the same thing. You can drop it in a jar of laquer thinner while the motor is warmwhich will dissolve the epoxy some so you don't need to work with a hot motor.

-Alex
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Old Aug 15, 2011, 05:10 PM
It flies or it dies
Russ The Flyer's Avatar
Deville, Louisiana
Joined Sep 2008
833 Posts
Quote:
Originally Posted by Dt.Serkan View Post
I rewound my motor and now it is better. I have another question about the epoxy glued wires on the stator. It is throughly an headache! I can not remove the wire espacially if the wire is thin. I found some information how to remove the glue as we can put the stator in an oven that heated about 250C for 10-15mins. Is there any easier solution of you for this situation? Thanks again.

_Serkan_
Hi Serkan. I too have just entered the rewind field. It's a real hoot to see one of my projects go.

I'd like to address your unwind problem. I use fingernail polish remover. It will dissolve the glue completely. Keep a skinny covered glass jar with a lid. The drop your motor in the remover and let it set for about an hour, swishing the motor around in the stuff in between. Then use something to hold onto the motor with and start your unwind. It should come unwound fairly easy.

Today I rewound a fairly new 3500KV motor that got fried. I used 24 GA wire doubled. I wound it with 5 winds and finished it in a Delta format. It gets very hot quickly. I had a 7X4 prop on it. I changed it to a 4.75X4.75 prop and it improved a bunch. But lost a bunch of thrust in the process. With a 3 cell lipo it screams but gets very hot. With a 2 cell it doesn't get quite as hot but also hasn't the push to fly the wing with.

I think I've learned a good bit by reading this thread. Especially about insulating the windings from the stator. Thanks for your knowledge in this Alex.

BTW one of my grandson's name is Alex.

Russ
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Old Aug 15, 2011, 10:44 PM
It flies or it dies
Russ The Flyer's Avatar
Deville, Louisiana
Joined Sep 2008
833 Posts
Success ... I think

Ok. I rewrapped the motor but this time I used only 3 turns with 20 GA single strand. I tried for 5 but couldn't cram all the wire into the stators. I checked each wind for continuity and found none. I put it together and mounted it on my wing. With a 2 cell it screams. Dunno if it will handle a 3 cell or not. With a 7x4 Screw Master prop it moves a lot of air and motor only gets slightly warm. I guess a flight test is going to tell me whether or not I was successful.

Russ
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Old Aug 17, 2011, 09:15 AM
Engineer for Christ
IBCrazy's Avatar
Amherst, VA
Joined Jun 2006
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Oh wow, 3 turns? I think you should look at 22 AWG or 24 AWG. These are my most common wire sizes. I doubt the stator is going to be able to handle a 3 turn. The eddy currents in the steel and hysteresis is going to nearly melt the steel stator on a 3S.

-Alex
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Old Aug 17, 2011, 09:52 AM
It flies or it dies
Russ The Flyer's Avatar
Deville, Louisiana
Joined Sep 2008
833 Posts
Hi Alex. 20 gauge wire is super hard to handle. But I figured the thickness would take care of the heat. When I test fly the wing I'll find out pretty fast. As it stands now I've got a 7x4 Master Airscrew prop on it. Probably really need a 6x4 but I'm fresh out. I ordered 12 from Tower Hobbies last night. But they won't be here until next Monday, probably. Though I have received stuff from them in 3 days so, who knows?

The stator is almost 1 inch long. The motor is an original 3500KV. Had 4 strands of 38 GA wire wrapped 14 times. I don't know why they use multi strand wire but I assume it's to keep juice flowing when one of the wires burns out and gives you a chance to bring it in.

BTW with a 3S lipo it screams. I star wound the motor to cut down on amperage. It stays pretty cool. I kind of followed your advise about getting more out of a star wind by cutting back on winds. 3 was all I could cram into the stators too. I tried 5 but couldn't get it to fit. Even using your idea of cramming the wire down with a propeller.

Russ
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Old Aug 27, 2011, 05:24 PM
It flies or it dies
Russ The Flyer's Avatar
Deville, Louisiana
Joined Sep 2008
833 Posts
Hi Alex. What is the advantage of using multi thin wires versus single thick wire to wind a motor?

Also how do they get so much RPM out of those motors? I've rewound one that had 7 winds with 6 strands of wire originally. I used 24GA single strand and did the same amount of windings but don't get half the RPM out of it. I've wired it both Delta and Star. The Delta turns over faster but I'm not getting the RPM's I had before. Before the motor got 3800KV. Now I'm lucky if I get much over 1899.

I understand that the fewer winds the faster the KV's.

Russ
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Old Nov 25, 2011, 03:50 PM
<- Balsa flies better ->
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Gustafs, Sweden
Joined Feb 2006
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Great article/guide, Thanks.

Peter
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Old Mar 27, 2012, 02:31 AM
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63 nova's Avatar
Lakewood, Colorado
Joined Apr 2009
152 Posts
I read through your whole thread twice and started rewinding my brushless 24 gram motor. I used 26 gauge wire and and followed all your instructions it took about 3 hours and no shorts and the motor runs great!! This is my first rewind but I think I will do all my motors now when they need it. Thanks for the great thread.
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Old Mar 29, 2012, 06:49 PM
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Mentor, OH
Joined Dec 2004
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we aim to please!
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Old May 03, 2012, 06:22 PM
TheyreComingToTakeMeAway!
derk's Avatar
USA, ID, Coeur D'Alene
Joined Dec 2003
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i tired heating my stator, but i still cant get the old windings off. its a turnigy 1811 10 gram motor.
what else can i do?
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Old May 04, 2012, 01:29 AM
It flies or it dies
Russ The Flyer's Avatar
Deville, Louisiana
Joined Sep 2008
833 Posts
Quote:
Originally Posted by derk View Post
i tired heating my stator, but i still cant get the old windings off. its a turnigy 1811 10 gram motor.
what else can i do?
Sometimes it just fights you. Get some finger polish remover (Naptha) and soak the stator in that overnight. The company that wound your motor used a kind of superglue to hold it all in place.

Sometimes you just have to take a screwdriver and gouge the wiring out.

Hope that helps.

Russ
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