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Feb 25, 2015, 05:15 AM
1 can never have 2 many planes
chambo88's Avatar
Thread OP
Help!

types of enamel coatings on copper wire.


hi guys,

been looking into re-wiring some motors i have.

just wanted to ask if anyone know's the type of enamel coating used on the copper wires. have seen different compounds ie; polyurethane etc..

which is best suited for electric motors??

cheers

88
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Feb 25, 2015, 06:29 AM
homo ludens modellisticus
Ron van Sommeren's Avatar
HobbyShack coated wire is not good, shorts.
Wire from www.gobrushless.com is excellent.

Wire insulation information
What wire to use to rewind a Dualsky Motor?
reinforcing the wires
Good U.S. sources for magnet wire?
Magnet Wire Question

Vriendelijke groeten Ron
Last edited by Ron van Sommeren; Feb 27, 2015 at 06:39 AM.
Feb 25, 2015, 12:19 PM
Registered User
vollrathd's Avatar

www.gobrushless.com


Quote:
Originally Posted by chambo88
hi guys,

been looking into re-wiring some motors i have.

just wanted to ask if anyone know's the type of enamel coating used on the copper wires. have seen different compounds ie; polyurethane etc..

which is best suited for electric motors??

cheers

88
You're half way around the world from here, but www.gobrushless.com has a variety of wire, for $$$$.

http://www.gobrushless.com/shop/inde...agnet+wire+std

Good grief. Amazon sells everything!
http://www.amazon.com/s/ref=nb_sb_no...+%2Cindustrial

Before retiring, the shop had a wide variety of magnet wire, ranging from 34 or so, up to #10. From there they went to flat sheets of copper for magnet wire. The varnish used was known as "Double Formvar", used in transformers and similar products.

They bought this stuff in 50 up to 250 pound spools. They always had the end of the spool wire available for other projects.
Feb 27, 2015, 04:09 AM
Registered User
Fourdan's Avatar
Hi
Informations here on different enameled wires
http://www.wires.co.uk
I am using "polyester 200C, non solderable", so I need to scratch mechanically the enamel (Xacto cutter).
I have no "Eraser stripper tool" (unfortunately)
Louis
Feb 27, 2015, 11:45 AM
1 can never have 2 many planes
chambo88's Avatar
Thread OP
Thanks for the replies. I guess im asking what is the most commonly used enamel coating on wires in brushless eletric motors?
Feb 27, 2015, 01:00 PM
Registered User
vollrathd's Avatar
Quote:
Originally Posted by chambo88
Thanks for the replies. I guess im asking what is the most commonly used enamel coating on wires in brushless eletric motors?
I suspect most varnish is fairly good for the type of motors we use. Check the magnet wires rated maximum temperature though. Some of that insulation is two steps better than chewing gum.

Also, I've used "Double Formvar" insulated wire from work. This stuff has problems when bent around very sharp corners like that found in our smaller motors. The varnish would crack at the sharp bends.

Using multiple strands per winding resolves this, and is likely one reason why the brushless motors use it.
Feb 27, 2015, 04:43 PM
homo ludens modellisticus
Ron van Sommeren's Avatar
Bevel/chamfer edges to prevent shorts on sharp edges.
Or dip stator faces in a thick coating.

More stator short precautions/remedies
Sticky: (Re)winding and building motors
→ opening post
→ items #14, #15, #16 and #17.

Prettig weekend Ron
Mar 01, 2015, 10:15 AM
Jack
jackerbes's Avatar
There is one major producer of magnet wire that is based in North America, that is the Superior-Essex company. You can see their basic product descriptions and download their product brochures here:

http://superioressex.com/MagnetWire/...ataSheets.aspx

If you really want to study the details of the coatings and the processes for soldering the various wires this brochure is a good start:

http://superioressex.com/uploadedFil...Wire/mwcat.pdf

The wires we use in motor rewinding are usually the wires that are rated for use at up to 155C/311F and 180C/356F and those use coatings that area called "Polyurethane/Polyamide (Nylon)".

A good supplier for our needs is this Tech Fixx person that sells in smaller quantities and via eBay. His internet page also describes the characteristics of the wire and coatings:

http://www.techfixx.com/

All things considered, Tech Fixx is arguably our single best source for acquiring good wire of known brands and quality. And Tech Fixx also gives us accurate descriptions of and good specifications for what we are buying.

The only point of confusion on the Tech Fixx wire page are the "solderable" descriptions on that web page. Those can be a little misleading if you don't know the processes and study the details a little. There are two types and they are described as:

Solderable: Yes, can be soldered without removing insulation/coating

Solderable: Insulation/coating must be stripped before soldering

When they say a wire is solderable they are not saying that you and I, working at home with simple tools, can simply apply heat and solder and get a good junction.

They are saying that it either is or is not solderable when that wire is used in a mechanized industrial process that involves the automated soldering of magnet wires. And that involves machines and fluxes and processes that none of us will ever have in our homes.

So the bottom line line is that if you want to get good solder joints when your rewind motors you are going to have to use slower and more laborious processes to strip the coatings. Fourdan has described it well when he says "..so I need to scratch mechanically the enamel (Xacto cutter)...".

There is simply no better way to ensure that the wire is bare of insulation and and ready to solder than to tin and inspect the stripped ends before you try join the wires for soldering. If it will not take a thin even coating of solder without any gaps or holes, it is not ready for soldering.

Post #5 in this thread show the tools and process I use for stripping, prepping, and joining the winding ends:

hexTronik DT750 Motor Rewind for Multicopter - www.rcgroups.com/forums/showthread.php?t=1892195

Using flux to get good solder joints is not a dangerous thing to do and it does not put solder joints at any risk of corrosion if you do it right. The image shows a six strand Wye bundle with the ends tinned and ready for soldering. When I touched a small drop of solder to the bundle of tinned ends it made for an instantaneous bundle of perfect conductivity. I snip about half of the tinned and joined length on the end off and put heat shrink tube over the bundle.

Jack
Mar 01, 2015, 11:37 AM
Registered User
I have used wire that I un wounded from old motors. Some of the best wire is from automotive fuel pumps. These motors are mounted inside the fuel tank and the gasoline is pumped through the motor to cool it. Yes, these motor run fully submersed in gasoline. The insulation has to be fuel proof and very good. Any other automotive motor would also have good wire.

Other places in the world may use cheaper wire in their autos but in the US the wire is very good.
Mar 01, 2015, 06:02 PM
Space Coast USA
hoppy's Avatar
Check your local area for a motor rewinding shop for alternators, pool pumps, etc. I got some good stuff from them for peanuts.

Radio shack magnet wire was terrible. Didn't take much to penetrate the varnish. Knowing the varnish used is not the whole story. How thick was it applied? Is it a flexible or stiff varnish, etc.
Somebody in the RC community (might be gobrushless) sells a beginners wire which has a more damage coating. I know that works good.
Mar 01, 2015, 07:37 PM
homo ludens modellisticus
Ron van Sommeren's Avatar
Go to your local friendly motor/transformer rewinder/refurbisher or repair shop. Excellent quality, all gauges, penny stuff, you'll probably get it for free if you bring your motor along. They love it when they can handle a motor without an overhead crane And maybe let them have a spin with your plane once you finished your motor? You know, in case you need wire again for your next motor

Scorpion motor winding: pictures and videos
Scorpion Factory Tour!
Scorpion Factor Tour II
Scorpion Factory Tour Today! III

Vriendelijke groeten Ron
Mar 01, 2015, 09:49 PM
Greediest Suer
Ron H's Avatar
Quote:
Originally Posted by mjsas
I have used wire that I un wounded from old motors. Some of the best wire is from automotive fuel pumps. These motors are mounted inside the fuel tank and the gasoline is pumped through the motor to cool it. Yes, these motor run fully submersed in gasoline. The insulation has to be fuel proof and very good. Any other automotive motor would also have good wire.

Other places in the world may use cheaper wire in their autos but in the US the wire is very good.
Never heard that before. I just swapped one out this weekend. I guess I'll open it up for the heck of it. I have been using beading wire for years without any problems. I tried it because it was cheap and easy to get here. Now it's the only wire I use.http://shop.hobbylobby.com/products/...g-wire-833061/


I should retract "only". But I use it more often than not.
Last edited by Ron H; Mar 01, 2015 at 09:59 PM. Reason: to edit
Mar 16, 2015, 12:56 AM
Registered User
And the enamel or varnish or whatever it is..stops shorts, and must not overheat and deteriorate so it can continue to stop shorts, right? And that's its sole purpose.

Which is the weaker link, the temperature at which the enamel will burn off and short or the temperature at which your magnets will hit their curie temp and lose magnetism?
Mar 16, 2015, 06:32 AM
Jack
jackerbes's Avatar
Magnets lose their magnetivity long before the wire coatings melt. The N38 and N50 magnets are intended to work well and continuously at up to 80C/176F (not 38C and 50C as I said in this post originally), insulation is good up to 155C to 200C depending on the quality of the wire and coatings.

Lots of good info on magnets here:

http://www.kjmagnetics.com/neomaginfo.asp

and here:

http://www.kjmagnetics.com/specs.asp

"N" magnets can run at up to about 80C or so, the better magnets (NM, NH, NEH, etc.) can go higher like as high as 200C on the best. As the temperature goes up so does the price and availability to us hobbyists.

Jack
Last edited by jackerbes; Jun 03, 2015 at 02:52 PM.
Mar 16, 2015, 07:21 AM
homo ludens modellisticus
Ron van Sommeren's Avatar
Handy magnettable with a.o. max. temperatures
www.supermagnete.com/data_table.php

Vriendelijke groeten Ron


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