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Old Jan 05, 2013, 09:59 AM
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Originally Posted by Odysis View Post
Wow - that looks like a hint of a distributed wind... I wonder why they've done that? How it affects the bEMF?
I personally think that hiding is not a good winding way. Anyway, I found in that way, a 8T should be views as a 10T. or nT should be viewed as n+2T
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Old Jan 06, 2013, 12:27 AM
Aka: Tom Jenkins
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So if I use the same wire I have been 1.5 mm it will work out if I keep it to 5 wraps per arm, the wire lays just right and with no crossover between it should lay even better. I'm guessing if I use string to get a wire length first them start winding each arm as I go and keep track of the tails, this way it could be done neatly.
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Old Jan 06, 2013, 12:38 AM
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Originally Posted by ApexAero View Post
So if I use the same wire I have been 1.5 mm it will work out if I keep it to 5 wraps per arm, the wire lays just right and with no crossover between it should lay even better. I'm guessing if I use string to get a wire length first them start winding each arm as I go and keep track of the tails, this way it could be done neatly. Wind three then loop the first over to the fourth and so on,,,
For ABCXn windings, Using just 3 wire (one complete wire for each phase/4 tooth) you can follow the winding sequence as: tooth_1, 3, 2, 5, 4, 7, 6, 9, 8, 11, 10, 12. Instead of 1, 2, 3, 4....12.
in this way, you may achieve better "shape" and better copper coverage. You will see how it works when you just follow the sequence once.
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Old Jan 06, 2013, 12:43 AM
Aka: Tom Jenkins
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I understand, your description gives me a good visual. Thanks Modisc!
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Old Jan 07, 2013, 07:02 AM
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I understand, your description gives me a good visual. Thanks Modisc!
I am afraid what you have done for your 12N10P 4035 should be a "10T" instead of 11T. since there are 10 thread of wire in each slot. Using the 6-wire technique, though from the upper surface, it was 5T on one tooth and 6T on the adjacent tooth, the 2 adjacent teeth actually share one T. So it was 5+6-1 = 10T
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Old Jan 07, 2013, 08:47 AM
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I saw that on the other site! I'm tomrex there....
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Old Jan 07, 2013, 07:03 PM
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I saw that on the other site! I'm tomrex there....
It seems it was still a 11T. I am very confused for a moment...
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Old Jan 07, 2013, 07:11 PM
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Modisc, I've been following this thread closely since it started, and I have to ask, if you don't mind, is English your first language?

I ask because I'm utterly impressed with your langauge skills if it is not!
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Old Jan 07, 2013, 08:33 PM
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Modisc, I've been following this thread closely since it started, and I have to ask, if you don't mind, is English your first language?

I ask because I'm utterly impressed with your langauge skills if it is not!
You can tell from my Asian face. No, i am Chinese.
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Old Jan 09, 2013, 07:33 AM
Aka: Tom Jenkins
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You're a handsome young man Modisc!
New question,
Is there a reason there are no cooling holes in/on an out runner can?
Seems a centrifugal force would flow more air. But, I'm guessing the steel can keeps any magnetic flux forces contained or something along those lines.
PS: #2 yy is done winding, getting neater!
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Old Jan 09, 2013, 08:03 AM
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You're a handsome young man Modisc!
New question,
Is there a reason there are no cooling holes in/on an out runner can?
Seems a centrifugal force would flow more air. But, I'm guessing the steel can keeps any magnetic flux forces contained or something along those lines.
PS: #2 yy is done winding, getting neater!
Yes, that "can" is the flux ring, made by material that can concentrate magnetic force lines.
For inrunners, the flux ring is on the stator, so the "can" is aluminium, simply for rigidity of the motor.

The Powercroco's 6 wire technique, is truely the ideal winding technique for 12N dLRK windings, which features every two adjacent teeth having opposite-direction coils. STSD creates too much connection ends, and for 12N dLRK, there seems to be no advantage over 6-wire technique. While 12N10P and 12N14P are now more commonly seen in the newer helicopter motors, the Powercroco's 6-wire YY winding becomes more popular.

Another important reason why the 6-wire technique is favorable, it that for YY, it has two Y-nodes that can be neatly arranged at the bottom of the stator. And YY can achieve the designated Kv range, considering the best wire size. For example, for a 4035 12N10P motor, the tooth length is around 8-9mm, which is suitable for 5 turns of 1.5mm wire (O.D. around 1.6mm) or 6 turns of 1.3mm wire (O.D. around 1.35~1.4mm) for the first layer. These two wire size can achieve very nice copper fill with appropriate winding technique (11T for 1.5mm wire, or 15T for 1.3mm wire). Using smaller wire, for example, 1.0mm, there will probably be more than two layers of coils on the teeth, and it will be nasty, while the copper fill is no better. Using bigger wire, for example, I tried 1.8mm wire to get 4+3T, but it is too difficult and still the copper fill is no better than 1.3mm 13T. Using YY or D connection, the Kv is basically within the range you need for your heli, while using Y will be too small, or DD will be too much.
So considering the above factors, the 6-wire technique is indeed favourable in many circumstances.

But the above is just my speculation.

For those ABC windings, like 12N8P, I still think the STSD is the superior winding technique, and those ends can also be arranged neatly.
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Old Jan 20, 2013, 06:50 AM
Aka: Tom Jenkins
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Hi guys, to keep the education going on the size wire I used in winding compaired to the factory wire size. The stock wind uses 27 strand of .29mm wire
I used a single strand of 14.5 gauge. Can you all guide me in how to figure the capacity difference of the new wind? I hope I asked the right question...
Tom
for 14.5 gauge the table reads 1.5367mm dia
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Old Jan 27, 2013, 06:27 PM
Aka: Tom Jenkins
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Another wire question with the cross section of wire compaired to the surface area. Do multipal strands have more or less surface area on the outside of the wire, not the circular area of a cross cut is what I'm trying to figure as I understand the electrons travel on the surface?
Next is, is there a dd or yy for a 12n8p? Where to find schematic?
Tom
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Old Jan 27, 2013, 07:32 PM
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Originally Posted by ApexAero View Post
Another wire question with the cross section of wire compaired to the surface area. Do multipal strands have more or less surface area on the outside of the wire, not the circular area of a cross cut is what I'm trying to figure as I understand the electrons travel on the surface?
Next is, is there a dd or yy for a 12n8p? Where to find schematic?
Tom
This (at least) is easy to answer.

For multiple strand wire, the surface area = N*pi* D, N being the number of strands, and D being the wire diameter. However since the two cross-sectional areas (=N*pi*D^2)/4 are the same, you get D_small=D_large/Sqrt(N_small)--since N_large=1.

So plugging this into the areas, you find that the surface area of the bundle (=N*Pi*D) of small strands is just Sqrt(N_small) larger than the single large wire.

In other words, 16 strands of small wire have 4 (=sqrt 16) times the surface area of a single strand which has the same cross-sectional area.
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Old Jan 27, 2013, 09:24 PM
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the effect is pretty negligable for us though.
Skin depth (the amount of copper actually conducting, more or less) is sqrt (2 * resistivity / 2*pi*frequency*magnetic permeability).
For copper, the constants are ρ=1.68e-8, μ=1.256e-6.

Assuming a PWM frequency of 32kHz (highest I've ever seen), that comes to:
sqrt (2 * 1.68e-8 / 2*pi*32e3*1.256e-6)
=.000356m, or .36mm.

So as long as the wire is <.75mm about 21AWG, you're golden. If you're using a 16kHz PWM, that doubles to about 14AWG.
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