Wire size comparisons - best winds?

[fly_boy99]

Folks I've found some good info on comparable ratios for winding DIY motors.


2 guage jump
=============
Each step down from say a 30g wire to a 28g, 28g to 26g, 26g to 24g, etc has a ratio of 1.59. So for example, say a 40T of 30g wire on a 22.7mm stator you would only need to wind the equivelent of 25T of 28g on the same exact stator.


3 guage jump
=============
The step down for a 3g jump like 26g to 23g the ratio is 2, so a wind of 26T of 26g wire on a 22.7mm stator would equivelently be wound with 13T of 23g wire on a 22.7mm stator.


4 guage jump [Note data is for reference only - these are extreme data points]
=============
The step down for a 4g jump like 24g to 20g the ratio is 2.52, so a wind of 20T of 24g wire on a 22.7mm stator would equivelently be wound with 8T of 20g wire on a 22.7mm stator.


6 guage jump [Note data is for reference only - these are extreme data points]
=============
The step down for a 6g jump like 26g to 20g the ratio is 4, so a wind of 26T of 26g wire on a 22.7mm stator would equivelently be wound with 6.5T of 20g wire on a 22.7mm stator. Let's call it 7T.

Hope that helps for all those new DIY motor builders out there. And yes sometimes there is an easier way to solve a problem...

Have fun building!
fb

[ecologito]

Great info FB, I am gonna add this info to the sticky thread, unless you wanna do that :D

[Impact]

I'm not sure I understand, If I had a stator wound with a single 26g and 17 turns and I changed to a single 22g and 7 turns wouldn't the KV of the motor go way up because of the lower resistance of the larger wire..Thanks ....Impact

[galloping gimp]

fb-

I don't understand what these numbers are designed to illustrate. In the examples, you imply that a motor with fewer turns of large wire is equivalent to one with more turns of smaller wire. That is not the case, and it's going to confuse newcomers!

To take just one example (6 guage jump), a motor with 26T of #26 is very different from one with 7T of #20. The total amount of copper on the stator might be similar, but the similarity ends there. The performance of the two motors will be quite different.

The 26T is a low Kv motor, producing high torque, low RPM, and suitable for a large prop. The 7T is a high Kv motor, producing low torque, high RPM, and suitable for a small prop.

What have I missed?

- Jeff

[Dr Kiwi]

I'm not sure I understand, If I had a stator wound with a single 26g and 17 turns and I changed to a single 22g and 7 turns wouldn't the KV of the motor go way up because of the lower resistance of the larger wire..Thanks ....Impact

You are partially correct - though the gauge of the wire has little to do with the Kv - it is largely the number of turns which determines Kv!

[ImaBiggles]

I think this is just how much 'fill' u get on a stator, nothing to do with Kv.

[Impact]

Thanks, I need all the help I can get. One more question; If I had a motor with 26g and ten turns that would draw X at X voltage and I wanted to change to 22g wire and still draw the same amout at the same voltage would this be correct, 10 x 2.52 = 25.2 turns of 22g....Impact

[BeavrdamElectric]

I'm not sure what you're asking here, but no way would a 10 turn motor be equivalent to a 25 turn, and no way would 25 turns of 22g fit on a GB stator.

Now 10 turns of 22g might fit in the same space as 25 turns of 26g. But the similarity would end there.

Good Luck!

[Impact]

What I'm thinking is just the total resistance of the wire. If 3 feet of 26g is X will it take 7.56 feet of 22g to match the resistance....Thanks....Impact

[BeavrdamElectric]

Resistance of the wire is only part of the resistance shown by a motor. Stronger magnets will raise a motor's resistance, and more turns will raise the resistance more than just the length of wire, due to back EMF.

Good Luck!

[Impact]

Ok, thanks...Impact

[Ron H]

Thanks, I need all the help I can get. One more question; If I had a motor with 26g and ten turns that would draw X at X voltage and I wanted to change to 22g wire and still draw the same amout at the same voltage would this be correct, 10 x 2.52 = 25.2 turns of 22g....Impact

A closer match would be 10 turns of 22g. Wire size has little effect on amp draw, it's the # of turns that matters most. Larger wire does increase copper fill though, so the motor should be a bit more efficient. The larger wire can also handle more current.

[KenSt]

I think what fly boy is refering to is the fact that windings can be scaled up or down without affecting the proper copper volume in the slot. For instance, three wire gage sizes lower and half the turns produces twice the rpm at the same voltage or.... the same rpm at half the voltage.

[fly_boy99]

Boy I didn't know I was going to cause mass confusion.

I was merely trying to show that you can build a more efficient more and same/or more copper fill per stator as those high turn count motors. I like to work smarter and not harder.

Beaverdam - For you I will do some experiments with a couple of different guages and how the differences in performance. This might better illustrate my point. I will build a test case where ONLY the winds will change and nothing else will.

Remember that higher guage wire has way lower resistence per 1000 feet. A 26g wire has a resistence value of 137ohm vs 34ohm for a 20g wire.

[fly_boy99]

I defintately say you are right but I think when you look at smaller jumps the delta is quite small.

Of course you went to the extreme and maybe I'll just take out the larger jump. I have added a note to the higher ratios on my first post. All I am trying to point out is that you can work smarter when building DIY motors.

I'll definately do some tests and post results to show the difference in copper fill with winds being the only thing that changes.

Should be interesting...

fb-

I don't understand what these numbers are designed to illustrate. In the examples, you imply that a motor with fewer turns of large wire is equivalent to one with more turns of smaller wire. That is not the case, and it's going to confuse newcomers!

To take just one example (6 guage jump), a motor with 26T of #26 is very different from one with 7T of #20. The total amount of copper on the stator might be similar, but the similarity ends there. The performance of the two motors will be quite different.

The 26T is a low Kv motor, producing high torque, low RPM, and suitable for a large prop. The 7T is a high Kv motor, producing low torque, high RPM, and suitable for a small prop.

What have I missed?

- Jeff

[qv_]

I like that AWG comparable ratios for winding DIY motors but I dont use AWG so I made it for mm2 area.
so if you have a motor with
20 turn 0.4 mm ~AWG26
and want 13 turn

20 / 13 X 0,126 = 0.194

and 0.5 mm = 0.196

so 13 turns with 0.5mm give the same copper fill as 20 turn 0.4mm
and if you wonder 0.4mm = 0.126mm2

/jan

the Rm dec, Kv inc. the motor will not be the same (but the copper fill will be).

[qv_]

you my need this

/jan

[galloping gimp]

I'll definately do some tests and post results to show the difference in copper fill with winds being the only thing that changes.

Should be interesting...
I agree. It would surprise the heck out of me if a motor with 25T of #28 is equivalent in performance to a motor with 40T of #30. Or that a motor with 13T of #23 is equivalent to one with 26T of #26.

But the beauty of it is that you can actually conduct the experiment and find out.

The matter of copper fill has been discussed many times, and there is no question that you should select a wire gauge that maximizes copper fill for a given number of turns. But what you're saying seems to be very different -- that two motors with greatly differing numbers of turns are equivalent as long as copper fill is maximized on both.

- Jeff

[olmod]

[QUOTE=galloping gimp]I agree. It would surprise the heck out of me if a motor with 25T of #28 is equivalent in performance to a motor with 40T of #30. Or that a motor with 13T of #23 is equivalent to one with 26T of #26.

But the beauty of it is that you can actually conduct the experiment and find out.


- Jeff[/QUOTE.
I have never read any comment on what effects such a comparisons has on the back EMF signal to the esc,i would imagine that the thinner wire would have more,wether one is better than the other esc wise would be an interesting question for the gods at CC. :)

[BeavrdamElectric]

Boy I didn't know I was going to cause mass confusion.

I was merely trying to show that you can build a more efficient more and same/or more copper fill per stator as those high turn count motors. I like to work smarter and not harder.

Beaverdam - For you I will do some experiments with a couple of different guages and how the differences in performance. This might better illustrate my point. I will build a test case where ONLY the winds will change and nothing else will.

Remember that higher guage wire has way lower resistence per 1000 feet. A 26g wire has a resistence value of 137ohm vs 34ohm for a 20g wire.

:confused:

Are you talking about what I was discussing in this thread?

http://www.rcgroups.com/forums/showthread.php?t=440258

Or are you talking about higher Kv motors being more efficient?

Good Luck!

[fly_boy99]

I think I'm getting at what is discussed in the thread you mention but definately going the other way. Instead of multistrand, going with larger wire with less turns.

How it turns out is to be known..

I'll post after I do some tests. I'm thinking of the following since alot of DIY's have this wire and do alot of DIY motors like so:

26g - I think the most popular wind is the 17T on a 22.7mm stator

24g - So whats the effect of doing 11T/12T of 24g with 22.7 stator

Then maybe:

24g - 12T

20g - 5T

I'd like to step up from 5T to probably 9T and see the effects. Granted a 5T motor will have a very high Kv.

fb

[BeavrdamElectric]

I don't see what you're trying to show. The accepted method (at least IMO) is to figure out what prop is appropriate for your plane and wind a motor to have the appropriate Kv for that prop, using the biggest wire that will fit. I tend to go for smaller props because a high Kv motor can be built with a few turns of thick wire and have low resistance for good efficiency. For me, single or multistrand depends on the # of turns and what will fit. Oh, and what I have on hand...

I'm waiting to see a Mega-Beater with 5t double strand 22g or at least 5t of 20g. The triple 26g is a little shy of 21g.

Lots of people have done the winds you list, except the 5t 20g. I did 7t of 20g for a gearbox motor. I've done 11t of 22g, 12, 13, and 14 of 23g or double 26g. My first motor was 17t of 26g which is popular but 17t of 25g is easy and I think 17t of 24 is doable.

Good Luck!

[fly_boy99]

Patience...patience.

Remember how everyone started out playing with 17T of 26g and now they are playing with 12T of 24G wire. Does it strike a chord now?

I've done 4T of 20g on a 22.7mm stator and I know how to get 6T on it which I will do very soon as the amp draw is HUGE on my triple GBx. Although it cannot be compared to a mega beater as it's only a GBx double.

[BeavrdamElectric]

Still mighty confused. A 17t and a 12t motor have different purposes. Different props for different planes.

A 6t 20g triple will be close to the 6t 20g 2.5 I did, no?

Good Luck!

[fly_boy99]

Didn't know you did a 6T 2.5... So why are you waiting for someone to wind a 5T 20g motor?

I will let the data speak for itself once I have it all and then I think your confusion will lift.

fb


Still mighty confused. A 17t and a 12t motor have different purposes. Different props for different planes.

A 6t 20g triple will be close to the 6t 20g 2.5 I did, no?

Good Luck!

[BeavrdamElectric]

Yeah, I posted data for a 6t 20g in the "Mega Beater" thread just before I did the 7t motor. That one gets hot quick with a 8x6 and 8c, 22+A. That led to the 7t, trying to see if I could make the Mega Beater do what Adrian wanted.

http://www.rcgroups.com/forums/showthread.php?t=389111&page=12&pp=15
Post #s 170 & 176.

5t of 20g will have a higher Kv. I'm not particularly in the market for that kind of motor DD, but I may wind one for a gearbox. I'll need to get a bigger ESC though, peak efficiency will be over 20A.

(After working with Drive Calculator a bit more it looks like I can use a 5t with a 6x4 on 8c, peak efficiency is more like 14A. I must have been thinking of the calculations for 4t of 18g, that puts the peak efficiency at 20A.)

Good Luck!

[fly_boy99]

I believe I can get 8T of 20g on a Gbx triple, as that's my next wind setup to replace the 4T 20G setup which is great for 2+ lbs of thrust on a 9050 but draws too many amps.

[BeavrdamElectric]

8t will certainly be a full stator! I hope you can do it, the results should be interesting!

Good Luck!

[mlh1961]

(After working with Drive Calculator a bit more it looks like I can use a 5t with a 6x4 on 8c, peak efficiency is more like 14A.

BEAVERDAM,

You and I sound a lot alike. I too am in search of the "Holy Graile" for the 6x4/6x5 prop. What Kv is the quoted 5t and what guage wire is it wound with.

I need to get something wound that will throw a 6x4 or 6x5 prop at a pitch speed of 80 plus mph. I think that's about 300 watts. The trick is, that I need to keep the draw down to 20-25 amps max.

Got any ideas?

Any help is greatly appreciated.

Mitch

[olmod]

(After working with Drive Calculator a bit more it looks like I can use a 5t with a 6x4 on 8c, peak efficiency is more like 14A.

BEAVERDAM,

You and I sound a lot alike. I too am in search of the "Holy Graile" for the 6x4/6x5 prop. What Kv is the quoted 5t and what guage wire is it wound with.

I need to get something wound that will throw a 6x4 or 6x5 prop at a pitch speed of 80 plus mph. I think that's about 300 watts. The trick is, that I need to keep the draw down to 20-25 amps max.

Got any ideas?

Any help is greatly appreciated.

Mitch
mmm 300w divided by 11v = 27amps mmmm i dont think so :(
maybe with 4 sp you may.

[mlh1961]

Thanks Olmond,

The battery I am planning on using is the MaxAmps 1500Mah-15c battery, it has a burst to 20c. So theoretically I can do it, just can't run WOT for extended periods of time.

[qv_]

Thanks Olmond,

The battery I am planning on using is the MaxAmps 1500Mah-15c battery, it has a burst to 20c. So theoretically I can do it, just can't run WOT for extended periods of time.

:confused: :confused: :confused: :confused: :confused:

The ESC turn battery on / off to the BL motor
if you have a mean value of 25 A on WOT
and mean value of 5 A on 1/4 throttle
the puls in A from the battery to the motor will be the same (time is different)

so ON amp is flowing then from battery to BL then OFF no amp

so if you cant run WOT you cant run 1/4 throttle

/jan

[mlh1961]

QV,

That makes absolutely ZERO since. If that were the case, I couldn't fly the set-up I have now, which draws 41 amps, from a MaxAmps 2100 15c-20c burst.

It DOES fly and quite well, AND I don't blow anything up, I just have to manage the WOT throttle time. But the plane WILL fly for almost 12 minutes at HALF throttle.

I am looking for a suitable wind that I can use, so I can take advantage of the lighter batteries, and a lighter plane.

[BeavrdamElectric]

(After working with Drive Calculator a bit more it looks like I can use a 5t with a 6x4 on 8c, peak efficiency is more like 14A.

BEAVERDAM,

You and I sound a lot alike. I too am in search of the "Holy Graile" for the 6x4/6x5 prop. What Kv is the quoted 5t and what guage wire is it wound with.

I need to get something wound that will throw a 6x4 or 6x5 prop at a pitch speed of 80 plus mph. I think that's about 300 watts. The trick is, that I need to keep the draw down to 20-25 amps max.

Got any ideas?

Any help is greatly appreciated.

Mitch

That's a mythical 5t at this point, a projection from existing data made by CP1's Drive Calculator (a VERY handy free tool).

http://www.rcgroups.com/forums/showthread.php?t=430584

Here are projections for a 5t of double strand 22g 2.5 with Strong curved magnets on 11V and 6x4 & 6x5.5 APC props. Note that they have to dissipate 75 and 85 watts so you need to keep an eye on the temp. This should be a more efficient motor than the Mega Beater but run at a higher power level (if your batteries are up to it).

"The battery I am planning on using is the MaxAmps 1500Mah-15c battery, it has a burst to 20c. So theoretically I can do it, just can't run WOT for extended periods of time."

I don't think this pack will hold 11V@25A. 10V may still be generous but the third pic is what it might do with 10V and the 6x5.5. (Just saw that you have a 2100, much more suitable for this type of motor. The extra weight may be worth it.)

Good Luck!

[mlh1961]

Thanks Beaverdam,

I at least I have some idea of where to start. I have also been watching closely the "Mega Beater" thread.

I have a few "kit" motors laying around, and a few "CDR's", so I have some stuff to work with. I just didn't want to throw money at components with out having some idea of what I needed.

Thanks again,

I'll keep you posted on what I work out.

Mitch

[Cutter7]

Can someone give me a quick answer. Im getting ready to wind another CD Rom motor. I have a 17T, 26ga, 5x5x1 Motor that gives about 7.5oz thrust with a 7x3.5 prop on a 2cell Lipo. Its on a 4oz plane and Rocks. Will a 12T 24ga Setup give me better results ?

[mlh1961]

Hey Beaverdam,

This is what I have. I have a 22x13mm stator, 9 slots and 6 13x5x1 n45 magnets.

It is wound with 11t of 22g single strand. Can you run the numbers for me and tell me what I can expect?

Thanks,

Mitch

[mlh1961]

Or what I need to rewind it at to get me in the 250 to 300 watt range and as close to 20 to 25 amps as possible.

I looked at the calculator, but....I'm not too computer litterate.

Thanks,

Mitch

[BeavrdamElectric]

You need some data to feed into the program, no-load volts, amps, and RPM, and the same with two or three different props (it helps if they're very different). Motocalc works off of no-load and one other data point and it's "motor designer" will do the same thing.

I don't have any data on a similar motor to base changes off of. The 13mm stack is pretty close to a triple but the 6 magnets kicks the Kv up to double what a 12 pole motor would have. Unless it's a GB stator, I don't know how much wire will fit either. But it sounds like it's already pretty close to a 5t double 22g with 12 magnets. The Strong curved magnets I used cut the current draw and raise the efficiency a bit. The extra turn (11 vs 5x2) probably has the same effect.

Good Luck!

[mlh1961]

thanks Beaverdam

The motor I have now draws 41 amps with a 6x4 prop. Needless to say I need to tone it down, cuz my batteries can't stand the strain.

[fly_boy99]

mlh1961

Knock that amp draw in half by adding 6 more magnet poles to your motor.

Clearly more efficient with more magnet poles.

fb

[BeavrdamElectric]

If you cut the Kv in half, you'll pull a lot less than 20A on the same prop.

Good Luck!

[fly_boy99]

I guess it depends on the wind.

Remember that 8T 20g Century Motor I was talking about. Well I actually did a 6 mag test on it to see how crazy it could get. Well you guessed it, with a 4.5x4.1 prop I got about 40A and when I changed to 12mag poles the amp draw dropped to 18A with the exact same prop!!!

This was kinda crazy because I first wound up the test with a CC25 and watch the guage go way up and my eye's almost popped out of my head!!! :rolleyes:

[jj1]

Would the prop revs drop 'too much' if magnet poles are doubled in this case?
I mean that 80mph pitch speed possibly wont happen without winding change.

BTW, did one test where fitted gb2,5 first with 6 mags/poles (NSNSNS)and then added 6 mags more (NNSSNNSSNNSS). Efficiency got only about 5% better.
Later arranged magnets to 12 pole configuration as 6 pole version was very ineffective on part loads.

-JJ

[BeavrdamElectric]

I'm guessing that an 11t 12 magnet triple with a 6" prop wouldn't be very useful unless you're running 5 or 6S.

Good Luck

[mlh1961]

Thanks, to all you for your input. I was foul I unwound the motor this morning, it was a 4 turn double strand of 22g.

I just got finished rewinding it with 6 strands of 30g and 11 1/2 turns, still 6 magnets. I'll check it out this afternoon.

Mitch

[BeavrdamElectric]

If I had known that I'd have gone for the 12 magnet setup.

Good Luck!

[mlh1961]

LOL, Thanks BD.

That is the beauty of these brushless motors, if you don't get what you want, just strip it and rewind it till you get what you want. I am going to order a 12 mag bell in the next couple of days.