Phase cable upgrade with magnet wire

[The Mighty Volt]

Ah.

I think I won't do anything until you guys have invented a fail-safe method. :lol:

Cheers.

 

[johnrobholmes]

With a strong enough heat source you won't have to worry about the varnish getting damaged too far down. It is easy to just remove a CM worth of insulation. Trust me on this, I wind motors daily and I have years of practice stripping the insulation for commutator terminations. The removal was my bane until I modified a spot welder for the task! By far, the easiest method is a bit of heat on the wire. The mechanical ruffing needed after the heat is very minimal, just to flake off the remaining charred bits.

If you are just doing one motor, by all means do what is most comfortable. But if you are planning to do this to multiple motors I suggest you give heat a try. Just practice on a little bundle first!

 

[John in CR]

why isn't this done from the factory...

I'm skeptical of the insulation on that wire and how necessary it is to have 7ga phases. 9-10ga is pushing it.

It turned out that with enough outside insulation for me to feel comfortable, I could only fit 10 strands of 18ga magnet wire for each phase, which works out to right at 8ga. Here's why I need 8 ga. On the left is my 10 strands, and on the right is what the motor is wound with. I certainly don't want the motor windings to sink heat away from the phase leads because the phase leads have more resistance.

 

[Chalo]

Remember that the phase leads are only carrying current, and won't be exposed to all kinds of magnetic eddy currents that also contribute heat. And the phase leads can reject that heat better because they're not in a can. They'll stay cooler, even if they are smaller (up to a point).

 

[Alan B]

Dipping magnet wire in a solder pot to remove insulation generally works quite well, I've been told. Lots of heat capacity in a few pounds of melted solder, very controlled, and tins the wire but does not overheat the copper like a torch. Small solder pots are pretty cheap in some places.

I have not tested this yet myself.

 

[CogHog]

why isn't this done from the factory...

I'm skeptical of the insulation on that wire and how necessary it is to have 7ga phases. 9-10ga is pushing it.

It turned out that with enough outside insulation for me to feel comfortable, I could only fit 10 strands of 18ga magnet wire for each phase, which works out to right at 8ga. Here's why I need 8 ga. On the left is my 10 strands, and on the right is what the motor is wound with. I certainly don't want the motor windings to sink heat away from the phase leads because the phase leads have more resistance.

I would hand sand and tin each strand of that 18 gauge before soldering the phase to motor winding. I would also separate the winding bundle to find the center wires are only tinned at the ends.
Also find solder with Silver in it to help with the reduced resistance. Imagine only tin is between those two wads of copper.

 

[John in CR]

why isn't this done from the factory...

I'm skeptical of the insulation on that wire and how necessary it is to have 7ga phases. 9-10ga is pushing it.

It turned out that with enough outside insulation for me to feel comfortable, I could only fit 10 strands of 18ga magnet wire for each phase, which works out to right at 8ga. Here's why I need 8 ga. On the left is my 10 strands, and on the right is what the motor is wound with. I certainly don't want the motor windings to sink heat away from the phase leads because the phase leads have more resistance.

I would hand sand and tin each strand of that 18 gauge before soldering the phase to motor winding. I would also separate the winding bundle to find the center wires are only tinned at the ends.
Also find solder with Silver in it to help with the reduced resistance. Imagine only tin is between those two wads of copper.

CogHog,

Yeah, I went the sanding route. The 18ga is stiff enough to make it pretty easy using sand paper. Then I inspected each end. Good idea on the silver solder, and I'll try that next time for sure. What I did to ensure a good low resistance connection is split each 10 wire phase bundle in half and put it on 2 sides of the soldered stub coming from the windings, overlapping the wires to be connected by about 1/2". Next I took a couple of strands of thin bare copper wire and wrapped the connection tightly together before fluxing and soldering.

I tried a quick experiment with some scraps first tinning each conductor, but I couldn't get the copper to lay as tightly together, so I decided to effectively tie and squeeze the connection together with very thin copper wire first. Then flux helped the solder really wick thoroughly into the joint. I can't believe I've been in this hobby for 3.5 years, but didn't discover the beauty of flux until a few months ago.

 

[CogHog]

John,

The flux should be cleaned out as much as possible. I used to use an ultrasonic cleaner with my connectors in a beaker full of Abcolene sitting in the sonic bay full of water (no need to fill the tank with chemicals). Had to solder a lot of brushed motor assemblies for satellites solar unfolding motors. Got to wind, vacuum varnish, balance these thumb size armatures.

Found R/C car racers using the silver solder and shortest wire lengths back 17 years when the batteries where the limiting factor on winning your race.

Also worked at PPL/BMC for 20 years. Chandu took over about 5 years back when I was designing microscope systems for PPL. My Bud still works there as I do side work from Orange county for PPL. He tells me of the Hub testing going on between Hi-power cycles and Chandu.
Just a heads up my Buddy was taking out green planetaries and replacing them with blue ones. I am not sure but a new Hub motors may be set up this way.

 

[CogHog]

I would try to mash down a wire with an arbor press to make a bigger wire fit the hole. You can re-paint the varnish or apply kapton tape to the back and one side. Looks like you may be able to get a 6 gauge in here. Hope this jpg posts.

httpwww.drillspot.comproducts670999approved_vendor_10638525_solid_building_wires=1

Hummm. Bought some and will try to press it into shape and trim to fit.

Got the wire today as I arrived at home. 10/3

 

[scriewy]

i got a bit confused here, why are we trying to use more bigger ga strands instead of more thiner strands ?

i thought the electrons run only on the radial surface of wires, and more thiner strands packed in the same diameter tube will have more radial surface than bigger ga strands packed into same tube.

 

[amberwolf]

AFAIK, that is only true of very high frequency AC. We're still working with what might as well be DC.

 

[scriewy]

Oh maaaan, where i am going to find info on solid big ga wire vs stranded big ga wire in DC stuff.

so in DC electrons dont move on the surface of wire ? or they do the same but there's another contributer to increase in resistance ?

if we take same purity solid wire Cu, same length, 1st 15ga other 10ga, we know 15ga at some point will start getting hoter and it's resistance will increase, why is that ?

i know from school more amps is more electrons flowing and bumping into conductors atoms, what excites the orbiting electrons in the atoms and creates heat and later light (if i remember ok).

so the colisions do heat, and if the colisions happen on the surface of solid wire the heat will go inward as well and simply to heat more masive ga solid wire requiers more colisions.
multistranded wire will have bigger surface in turn less colisions and less heat.

question is where do the colisions happen in DC.

 

[ian.mich]

save the trouble, buy 12g HK wire, heatshrink individually, e-tape the lips of the exits to protect the isnulation, leave the stock hall wires or replace with 30awg teflon (before doing the phases) then carefully put the phases through, the hall wires help shield the heatshrink from scraping as well as e-taping the exit lips. afterwards, use lots and lots of silicone.

 

[John in CR]

save the trouble, buy 12g HK wire, heatshrink individually, e-tape the lips of the exits to protect the isnulation, leave the stock hall wires or replace with 30awg teflon (before doing the phases) then carefully put the phases through, the hall wires help shield the heatshrink from scraping as well as e-taping the exit lips. afterwards, use lots and lots of silicone.

I wouldn't trust anything, except maybe the easy to get to low power thin wires, to a single layer of shrink. One nick in it and all your work and your high power controller are history. Risking scraping up your hall wires in the suggested manner has failure written all over it too.

Going to big gauges for the foot or so inside the motor is a waste of effort for most hubbies though. It's no use going to much effort to go bigger than what the motor is wound with. Once you're outside of the motor where it's easy then bigger gauge to reduce resistance is cool, but it's only worth forcing it that last foot on motors with low turn counts. Think of how long each phase is just in the windings.

John

 

[ian.mich]

save the trouble, buy 12g HK wire, heatshrink individually, e-tape the lips of the exits to protect the isnulation, leave the stock hall wires or replace with 30awg teflon (before doing the phases) then carefully put the phases through, the hall wires help shield the heatshrink from scraping as well as e-taping the exit lips. afterwards, use lots and lots of silicone.

I wouldn't trust anything, except maybe the easy to get to low power thin wires, to a single layer of shrink. One nick in it and all your work and your high power controller are history. Risking scraping up your hall wires in the suggested manner has failure written all over it too.

Going to big gauges for the foot or so inside the motor is a waste of effort for most hubbies though. It's no use going to much effort to go bigger than what the motor is wound with. Once you're outside of the motor where it's easy then bigger gauge to reduce resistance is cool, but it's only worth forcing it that last foot on motors with low turn counts. Think of how long each phase is just in the windings.

John

so what would you recommend if one was to do non magnet wire then? i dont trust the varnish on that

 

[John in CR]

save the trouble, buy 12g HK wire, heatshrink individually, e-tape the lips of the exits to protect the isnulation, leave the stock hall wires or replace with 30awg teflon (before doing the phases) then carefully put the phases through, the hall wires help shield the heatshrink from scraping as well as e-taping the exit lips. afterwards, use lots and lots of silicone.

I wouldn't trust anything, except maybe the easy to get to low power thin wires, to a single layer of shrink. One nick in it and all your work and your high power controller are history. Risking scraping up your hall wires in the suggested manner has failure written all over it too.

Going to big gauges for the foot or so inside the motor is a waste of effort for most hubbies though. It's no use going to much effort to go bigger than what the motor is wound with. Once you're outside of the motor where it's easy then bigger gauge to reduce resistance is cool, but it's only worth forcing it that last foot on motors with low turn counts. Think of how long each phase is just in the windings.

John

so what would you recommend if one was to do non magnet wire then? i dont trust the varnish on that

Do like LFP and shrink each phase and then everything including the halls goes in a larger shrink that gets it more round anyway.

BTW you are trusting the varnish on every ride with magnet wire wrapped on every tooth. What I like about the magnet wire is that is does have a thin high temp dielectric on each strand, so all 3 phases can go together in the one bundle. Then I wrap with a single layer of electrical tape for a secondary very thin layer of protection and to get it shaped nice and round, and then shrink goes over that. That's 3 layers before you get to copper, and a nice round shape to go thru the hole for less wasted space. The compromise is getting that damn varnish off at the ends to join the strands forming each phase.

 

[ian.mich]

yeah trusting varnish doesnt seem like a great idea, but you are right that it is technically the best way of doing this and once you have it in place without any scratches, you're probably not going to have any issues especially if you epoxy the tube to cement the whole thing in place. what you described is exactly what i was thinking, heatshrink individually then heatshrink it with larger heatshrink. likely going to do just that with 12g HK wire and 30g teflon ebay wire, and of course lots of ebay heatshrink.

 

[ian.mich]

what i've ended up doing is making a harness to go down the tube using individually shrinked 14g HK wire just for the tube, and using 12g for the connections btwn the tube and the windings, and between the tube and the controller. should be decent for 24s 60A.

 

[Farfle]

We ran 6 strands of 16awg mag wire into a 9C axle after slightly drilling/smoothing the innards. Each pair of mag wires went in with a small heatshrink over it, then the whole bundle including the hall wires got shrink tubed. It went in with a little silicone as lube, cured up and worked well.

 

[ian.mich]

We ran 6 strands of 16awg mag wire into a 9C axle after slightly drilling/smoothing the innards. Each pair of mag wires went in with a small heatshrink over it, then the whole bundle including the hall wires got shrink tubed. It went in with a little silicone as lube, cured up and worked well.

what power are you running?

 

[Farfle]

will be running either 66 or 88v around 60A on a 7 turn 20" wheel.

 

[John in CR]

what i've ended up doing is making a harness to go down the tube using individually shrinked 14g HK wire just for the tube, and using 12g for the connections btwn the tube and the windings, and between the tube and the controller. should be decent for 24s 60A.

LFP got 10ga of thin strand for each phase into a 9C axle, so it would have been a lot easier to just run the 12ga the whole way. To me outside the motor 12ga isn't sufficient. You'd be surprised how much phase wires heat up at even modestly high power. That's pure losses that can be easily avoided. Plus hot phase wires outside means even hotter phase wires inside, which is a common failure point. There's no such thing as overkill with primaries cabling, batteries, and torque arms/dropouts.

John

 

[ian.mich]

what i've ended up doing is making a harness to go down the tube using individually shrinked 14g HK wire just for the tube, and using 12g for the connections btwn the tube and the windings, and between the tube and the controller. should be decent for 24s 60A.

LFP got 10ga of thin strand for each phase into a 9C axle, so it would have been a lot easier to just run the 12ga the whole way. To me outside the motor 12ga isn't sufficient. You'd be surprised how much phase wires heat up at even modestly high power. That's pure losses that can be easily avoided. Plus hot phase wires outside means even hotter phase wires inside, which is a common failure point. There's no such thing as overkill with primaries cabling, batteries, and torque arms/dropouts.

John

you were right, re-did it with 12g HK wire and it slid in easy as can be. gonna run that and 10g outside the motor, 18fet 4110 60A controller with 24S3P, air cooled.

 

[scriewy]

nice to continue this.

i ended up testing 1 3mm wide desoldering wire by hooking to PSUs positive to feed icharger1010 to charge my batteries, and upping the current in steps, at 12v 14A through the wire, temp was 50c wich i decided to be the limit, so i put 5 strands of desoldering wire as 1 phase only along the axle groove and shrinked them, was easy to work with and they are flat space smart, that was our goal if i remember, and some 1 even tried to use rectangular solid copper wire but hard to work with.

so i peak 80A on starts 12 fet 4110, and usualy draw 40A till i pity my batts and fall to 20A, with 2 phases of regular 12g, holding ok in terms of not melting the shrink for now.

 

[John in CR]

...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?