Phase cable upgrade with magnet wire

[Farfle]

...holding ok in terms of not melting the shrink for now.

I thought good shrink can handle much higher temperatures than typical insulation on wire.

Also, by desoldering wire, do you mean braided solder wick?

most shrink I have used is 150c, but it probably fails at a higher temp, which probably beats 90% of standard pvc insulation. a quick google search shows ptfe shrink that's good to 180C

 

[scriewy]

...holding ok in terms of not melting the shrink for now.

I thought good shrink can handle much higher temperatures than typical insulation on wire.

Also, by desoldering wire, do you mean braided solder wick?

yep braided solder wick, the reason was coz of the crazy amount of wires, more than any special extra stranded wire i'v come across, but that was then, befor last month i stumbled upon couple years old thread where some 1 linked to a litz/s wire associated with skin effect i was searching for.

the moment the strands are not isolated per strand, it acts as 1 body and will not help with skin effect at frequencies above 60khz where it starts to become an issue to any wire at high currents, frequencies which lucky for us our controllers dont use.
Õnly gain in solder wick is it's flexibility and shape.

i could stuff more layers per phase, but i was testing how 5 wires would hold.

the 50c limit i set was at room temp 24c, in reality when together they'l help eachother to warm and the shrink will keep them warm so they might reach 60c, now take it outside where ambient temps in israel sun 55-60c and put it in axle groove which will help heat even more from what ever is left off a 120c hub.
my simple shrink morphs at 125 and farfle says fails at 150 and i aint running 70a continues so maybe it's pretty conservative.

oh yea i also put kapton tape as last resort if shit hits the fan (damn it cant put smilies from my phone)

skin effect - as frequency rises the electrons travel less and less in the iner part of the wire and more closer to the outer walls of the wire, so 10A at 500hz in 10G wire will travel through the hole cross section of the wire, at 500khz electrons will travel in less than 0.02mm depth of wire in outer part (0.02mm penetration from the walls). It's an example, i dont remember the chart.

same current travels through less wire material so we get more resistance and heat.

 

[John in CR]

Anything smaller than the individual strands used to wind the motor is a waster, because the windings are longer. We don't have to worry about skin effect. Finer stuff doens't pack as well, and braided packs even less well. Is solder wick even 100% copper?

If your motor is getting to 120°C, then you need to ventilate it, because it's too hot.

Your goal should be as little resistance as possible, though that 30cm or less from the solder connection at the windings to outside of the axle doesn't need to be any larger than the effective gauge of wire in the bundle used to wind the motor, so don't strain yourself trying to go too big unless you have a really high Kv hubbie. You can always go larger outside of the axle.

 

[ian.mich]

what i've been doing the past few days is converting 6 hubs (pro 901s and a couple "350w" mini motors) to larger wiring. took about 1hr each from strt to finish. I put tape over the lips of the wire axle, left the stock hall wires, took out the phases, heatshrinked 3 pieces of 12g turnigy wire using 4mm shrink, slid them down the axle like butter, soldered to the windings, then epoxied in place at the two entrances. Then run 10g turnigy wire from the motor to the controller. seems to handles 6kw no problemo, and its easy as can be.

 

[e-beach]

OK, back to the OP... I am about to upgrade phase cables in a yescomusa motor that I bought. Now, I have a bunch of magnet wire from other motor experiments and I trust the insulation on the mag wire to keep my motor phase cables insulated. If it doesn't short in your motor why would it short in your wiring harness? (See the YT link below.) Besides I am only running a 30 Ah controller and probably won't upgrade on this motor further then 35 or 40 Ah one.

In a previous post of mine, Dnmun stated that some people, when upgrading phase wires use 12 AWG THHN housing wire. That is single strand wire. The 10 AWG magnet wire I have is actually thinner then insulated 12 AWG THHN so I could use my 10 AWG magnet wire instead of the THHN Dnmun suggested.

Now, I have magnet wire in these diameters:
10 AWG, 19 AWG, 22 AWG, 24 AWG, 26 AWG, 30 AWG, 32 AWG.

I also have plenty of 22 AWG hook-up wire in many colors like: Black, Red, Blue, Green, Yellow and Orange.

What I don't have yet is the shrink tubing because I am not sure of the final diameter of the cable I am going to build. Once I get my mag wire cable made I will get the appropriate shrink tubing for a nice tight fit.

The issue of insulation removal on the mag wire can be time consuming, but I have removed it in the past with a cigarette lighter and some fine grain sand paper. To stop the heat from running down the wire I just wrap the wire in a wet paper towel. Adding a bit of color coded shrink tubing inside the motor, once the cable is in there to protect against any weakened mag wire insulation would be easy.

So my question is this:

Should I go the easy way with the 10 AWG mag wire and some hook up wire with 90c insulation, or should I go with a combination of magnet wires to get a multi-strand efficiency?

Any and all thought would be appreciated!

PS. Check out this video about magnet wire insulation durability. It is from TEMCo. That is the place that I bought my 10 AWG magnet wire.

http://www.youtube.com/watch?v=tFgpmLOpYbs&feature=relmfu

 

[ian.mich]

Do either 10g mag wire properly shrinked individually (and ~200C wires for halls if you do that replacement), or do 12awg milspec teflon. i use this stuff in my products.
http://www.ebay.ca/itm/180993936341?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

 

[John in CR]

You have a bend to get by, so no way on a single strand of 10ga. That means the 19ga, but for modest power, I wouldn't go to the all the trouble unless your magnet wire is going to waste otherwise and you want to save a few bucks.

Don't do it the way Ian does though. There's no way of being certain you don't damage or weaken the insulation on a hall wire doing it that way. The halls are the easiest to re-terminate anyway, so put them inside whatever outer protection you use for the harness.

John

 

[ian.mich]

You have a bend to get by, so no way on a single strand of 10ga. That means the 19ga, but for modest power, I wouldn't go to the all the trouble unless your magnet wire is going to waster otherwise and you want to save a few bucks.

Don't do it the way Ian does though. There's no way of being certain you don't damage or weaken the insulation on a hall wire doing it that way. The halls are the easiest to re-terminate anyway, so put them inside whatever outer protection you use for the harness.

John

oh ive come a long way john, i leave the stock halls in and put 3mm turnigy shrink down to the piece of fiberglass inside, then from the inside to the outside i slip the tough 12awg teflon. stewrobb uses 10g mag wire and out of some impossible feat he manages to get it around the bend. ive gone over the logisitics of it and tried it a bunch of diff ways, i dont get it.

 

[e-beach]

stewrobb uses 10g mag wire and out of some impossible feat he manages to get it around the bend. ive gone over the logisitics of it and tried it a bunch of diff ways, i dont get it.

When you say "get it around the bend" do you mean the "bend" on inside opening of the axle?

 

[ian.mich]

stewrobb uses 10g mag wire and out of some impossible feat he manages to get it around the bend. ive gone over the logisitics of it and tried it a bunch of diff ways, i dont get it.

When you say "get it around the bend" do you mean the "bend" on inside opening of the axle?

exactly, thats the toughest part of the wire upgrade usually

 

[e-beach]

exactly, thats the toughest part of the wire upgrade usually

Thanks! I will be thinking about how to get around that bend and post if I figure something out.

 

[John in CR]

After thinking about it the three 10ga solid wires plus the halls first wrapped with a single layer of electrical tape to get them nicely organized and parallel with no twisting and crossing each other before a layer of shrink, might work nicely. I've found the tape saves more room by good organization of the wires than it use, but only a single layer with no overlap. Stagger the ends of the 10ga by 1cm or more to get the ends past the bend and out first. Also curve the very end of each to help initially get the end inside the motor thru. I've stuffed some quite stiff bundles and gotten them thru the bend at the inside by pushing the outside end while at the same time pulling the inside end. Just pulling or just pushing one end won't work, but doing both at the same time works wonders. Your advantage with the single solid strand is that it is much smaller. While 3 don't form a very good circle, the hall wires will fill in the gaps well. Include a pair of your 24ga magnet wire inside the bundle in case you want to install a temp sensor later or you damage a hall wire at some point.

I think I'll try some big solid core next time I reharness a motor. If someone did it, then it's possible. Maybe some grades of wire are more pliable. Try a dry run first and if you can get a few cm thru, then you know it's possible and use silicone as sealant and lube at the same time. Have needle-nose pliers ready, and if you use silicone be sure to let it cure for at least 24 hours before closing up the motor, so you don't get an acetic acid residue settling on interior parts and getting crazy corrosion for nothing.

John

 

[ian.mich]

After thinking about it the three 10ga solid wires plus the halls first wrapped with a single layer of electrical tape to get them nicely organized and parallel with no twisting and crossing each other before a layer of shrink, might work nicely. I've found the tape saves more room by good organization of the wires than it use, but only a single layer with no overlap. Stagger the ends of the 10ga by 1cm or more to get the ends past the bend and out first. Also curve the very end of each to help initially get the end inside the motor thru. I've stuffed some quite stiff bundles and gotten them thru the bend at the inside by pushing the outside end while at the same time pulling the inside end. Just pulling or just pushing one end won't work, but doing both at the same time works wonders. Your advantage with the single solid strand is that it is much smaller. While 3 don't form a very good circle, the hall wires will fill in the gaps well. Include a pair of your 24ga magnet wire inside the bundle in case you want to install a temp sensor later or you damage a hall wire at some point.

I think I'll try some big solid core next time I reharness a motor. If someone did it, then it's possible. Maybe some grades of wire are more pliable. Try a dry run first and if you can get a few cm thru, then you know it's possible and use silicone as sealant and lube at the same time. Have needle-nose pliers ready, and if you use silicone be sure to let it cure for at least 24 hours before closing up the motor, so you don't get an acetic acid residue settling on interior parts and getting crazy corrosion for nothing.

John

you gotta put shrink over each of the 10ga or they will rub together and short with just one piece over all 3.

 

[e-beach]

After thinking about it the three 10ga solid wires plus the halls first wrapped with a single layer of electrical tape to get them nicely organized and parallel with no twisting and crossing each other before a layer of shrink, might work nicely.

After a quick check of three pieces of 10awg that was my conclusion also.

Stagger the ends of the 10ga by 1cm or more to get the ends past the bend and out first. Also curve the very end of each to help initially get the end inside the motor thru. I've stuffed some quite stiff bundles and gotten them thru the bend at the inside by pushing the outside end while at the same time pulling the inside end. Just pulling or just pushing one end won't work, but doing both at the same time works wonders.

Sounds like what I once did when I helped an electrician friend of mine pull electrical wires through conduit when building a video editing bay in Hollywood. It is how I was thinking about doing it as well.

 

[e-beach]

you gotta put shrink over each of the 10ga or they will rub together and short with just one piece over all 3.

Is this true? Magnet wire enamel is tuff-stuff.

 

[amberwolf]

The idea of the outer single heatshrink would be to securely tighten all of them together so they couldn't rub against each other in the first place, and ot prevent any of them from rubbing against the axle itself.

If whatever wires you use are securely against each other, they can't move, and can't rub. If there is any wiggle room at all, then yes, they could rub, and would eventually wear thru any insulation you put on them.

 

[John in CR]

you gotta put shrink over each of the 10ga or they will rub together and short with just one piece over all 3.

Is this true? Magnet wire enamel is tuff-stuff.

Motor wires don't have anything and they have room to move, also countering AW's point. The purpose of the silicone is to prevent water entry, but it will also help secure the harness and prevent chafing. The whole reason to use magnet wire is to avoid needing thicker insulation between the phase wires. Otherwise just use regular wire and skip the termination hassles, so no, no need for shrink on each.

BTW, I wouldn't go the burning it off route. With just 3 conductors scrape and sand them nice and clean, nice and easy.

John

 

[ian.mich]

you gotta put shrink over each of the 10ga or they will rub together and short with just one piece over all 3.

Is this true? Magnet wire enamel is tuff-stuff.

Motor wires don't have anything and they have room to move, also countering AW's point. The purpose of the silicone is to prevent water entry, but it will also help secure the harness and prevent chafing. The whole reason to use magnet wire is to avoid needing thicker insulation between the phase wires. Otherwise just use regular wire and skip the termination hassles, so no, no need for shrink on each.

BTW, I wouldn't go the burning it off route. With just 3 conductors scrape and sand them nice and clean, nice and easy.

John

Each to their own, but personally i would never want just the enamel between wires. It seems like shrink is overkill but in the end its really whats warranted for this situation. luckily, id like to think 12g teflon is on par. the shrinked mag wire will still be thinner than shrinked stranded and have 2 layers of really strong insulation, seem like a much better solution than 3 in 1 shrink

 

[Alan B]

Teflon cold flows, avoid pressure on teflon insulation, or tight bends.

THHN is available in both solid and stranded form.

 

[Chalo]

Teflon cold flows, avoid pressure on teflon insulation, or tight bends.

Agreed. Teflon jackets go hand-in-hand with fine stranded wire for that reason. Kapton tubing is harder. Frankly, I wouldn't use either one with solid wire. Solid wire in a too-tight metal conduit is just a dull nipper for whatever insulation you have.

 

[ian.mich]

isnt THHN like 90 celsius? i want 200C minimum inside a motor

 

[e-beach]

isnt THHN like 90 celsius? i want 200C minimum inside a motor

The 10 AWG magnet wire (motor wire) I am going to use is 200C.

 

[ian.mich]

isnt THHN like 90 celsius? i want 200C minimum inside a motor

The 10 AWG magnet wire (motor wire) I am going to use is 200C.

exactly why would one use THHN

 

[e-beach]

exactly why would one use THHN

Hard to know...maybe the extra work of magnet wire... :wink:

To show what I am going through, first I played around with different configurations...

Found that John in CR was spot on with his instruction of tightly wrapped wires with electrical tape then heat shrink. Below is my mach-up of what my wires exiting my shaft will look like.

My axle has a 7mm bore so the idea is to keep the magnet wire, tape and shrink wrap under 7mm the length that is going through the axle.

 

[ian.mich]

yeah but thats a 10 gauge harness thats under 7mm wide, 10 gauge thhn is gonna be waay wider