Show your CD / self made motors

[ecologito]

Here are a few motors that I've done before :)

[stirlingnut]

here are some of mine

[MorrisM]

Here are a couple of mine.

[ecologito]

Here are a couple of mine.

MorrisM, You have some really sweet looking bells, I have some 35 mm stators but don't have a lathe yet, I am thinking in the future ( in about 1 month I'd like to work on this projects, would you be able to turn a couple of bells for me? and how much would you charge me for it?

Here are pictures of the stators I have.

[MorrisM]

Ecologito,

Those big stators look interesting. I have been wanting to build some bigger motors, but really don't have time right now. Maybe in a few months.

Morris

[Ron H]

24 turns of 26 gauge is impressive on a 20mm stator. 22 is max for me on the stator, 18 for a stock can. It was brought to my attention by Don that just because the wire fits it doesn't mean the can can.

[ecologito]

24 turns of 26 gauge is impressive on a 20mm stator. 22 is max for me on the stator, 18 for a stock can. It was brought to my attention by Don that just because the wire fits it doesn't mean the can can.

The can I use is not from the same motor I got the stator out. The can came from a 1.5 cms high motor and this stator is only 1 cm high.

[turbine01]

I am interested in doing DYI motors , and understand pretty much how they go to gether accept for one thing.
I know there are 3 wires going to the ESC from the windings, but where do the other 3 ends of the wires attach to after they are wound on to the stator.

[olmod]

If you are using a Y or star connection scheme, the ends are joined together and covered with a piece of blue heatshrink.

[ecologito]

This are the two options:

Y termination

http://www.strongrcmotors.com/Instructions%20Strong%20Motor_files/image012.jpg


Delta termination
http://www.strongrcmotors.com/Instructions%20Strong%20Motor_files/image014.jpg

About the " best" termination it's totally up to what you are using it for.

[skippy hop hop]

those diagrams are very usefull but what advantages do both ways of winding what are the pros and cons of both types

[ecologito]

those diagrams are very usefull but what advantages do both ways of winding what are the pros and cons of both types

I went through some posts and this are some quotes I found about the topic:


" Let me put it this way, a 17t delta motor is roughly the equivalent of a 10t wye motor. In other words, wye vs. delta is just another way of talking about how many turns you want to put on your motor. The key here is that the single most important thing you can do to affect the character of your motor is the number of turns. Termination (wye or delta) is just another aspect of the number of turns, and is NOT a seperate variable." - Tolladay


" Said another way Delta and Y connected motors will perform virtually the same if the Delta Motor has 1.73 times more turns and uses EDIT smaller EDIT wire area (to get the same "fill" of copper)." - Don

"Using a GBx triple stator
20T/26 ga wire
12 15x4x2 N50 magnets

GWS 9x7 prop
Wye Wind
Kv = 470
No load current = 0.2A
9.1 oz of thrust
2.6A / 32 W

GWS 9x7 prop
Delta Wind
Kv = 844
No Load Current 0.5A
18.5 oz thrust
10.7A / 114W" - costath

I hope this references help a bit if you want detailed information the Thread I found the quotes is:
http://www.rcgroups.com/forums/showthread.php?t=372669

Good luck

[ralfsmith]

Can you provide me more information on this matter?

johntvery@operamail.com

johntvery@hotmail.com

[turbine01]

Thanks Ecologito that explains a lot, and it looks like the Wye wined is simpler than the Delta. I mean they are both simple, but with the Delta more care must be taken in keeping track of what ends should attach to what end. :cool:

[turbine01]

Also can you get DYI kits for larger outrunner motors?...Like the E-Flite .46 and .60 size.

[ecologito]

Also can you get DYI kits for larger outrunner motors?...Like the E-Flite .46 and .60 size.

Here is a source of biger motors that the regular cd:

http://www.torcman.de/shop/index.html

If you want something specific you could contact Ralph

www.powerditto.de

[turbine01]

Thanks Ecologito....Looks like to good sites, and what I am looking for. :)

[ecologito]

I am almost done with this motor, I am waiting on magnets but I might get them in a couple of weeks but here is the turned bell for my 35mm stator :)

[Ron H]

Looks good. What area are you considering in the Carolinas?

[Art Newland]

Here's my latest. GBL 22.7mm stators X 10mm.

[DadHav]

Here are a few of mine, in case you might be interested.
John

[latrans]

John,

I've been wondering when you'd show off some of your work here at rcgroups. Have you told anyone else about your corvet motor, I think alot of people here would find it interesting.

Adam

[ecologito]

...

[ecologito]

Looks good. What area are you considering in the Carolinas?

I am moving to Lake Wylie SC, 20 min. away from Charlotte.

Here are a few of mine, in case you might be interested.
John

:eek: Man your motors look awesome I hope someday my motors will look as cool as yours, I have turned only one bell and since I don't have a lathe at home I don't have a lot of time to practice but I will get me one and practice more :)

[ScubaSteve]

john you never cease to amaze me:) What's this corvet motor?;)

[DadHav]

John,

I've been wondering when you'd show off some of your work here at rcgroups. Have you told anyone else about your corvet motor, I think allot of people here would find it interesting.

Adam

Hi Adam. You here too?
The CorVet as I call it was a test for Don at Strong RC Motors. This incidentally is a GB parts motor also. I wanted to see if his kit could run pretty hot and fast without burning up. I would say it passed a pretty good test. I was drawing over 23 amps with it and it just got warm. She was really moving. This motor has strong rounded magnets and is very underrated. I later wound it a little more practical, lightened it up by filing vents and a few other things, and used the motor for the very popular Flying Hydro (Miss Hanger One) The motor was a perfect match for the kit, in my opinion. The ship came out to be just less than 12 ounces and the motor pulled 18 ounces thrust with a GWS 7-3.5 prop while drawing just less than 10 amps static. I don't know if you saw the original test video but maybe you can get there using one of these links. I also have the test for a 45mm stator motor. I think you probably saw that one. Also a picture reference showing some machining steps.
http://media.putfile.com/GBx-Plus-Super-Modified-Motor
http://media.putfile.com/Weapon-Motor
http://pg.photos.yahoo.com/ph/dadhav44/album?.dir=/eb4c&.src=ph&.tok=phpXAJEB59F0LBU
This probably won't work, Right?

[ecologito]

Very cool pictures, I need to g oand get some new lathe bits.. then I need to learn how to use them LOL thanks a lot man.

[Ron H]

Someone is shooting you a line, ecog. I'm right on that line, but it takes me 15 miniutes to get to Florence, 1 full hour to get to Columbia, 1.5 before I can park. Still quite lame compared to Mexio City.

[olmod]

Where do I start :) super presentation,I know from my own experience the hours you must be putting into each motor build :) like myself you grind your own bits/cutters,i love your collet chuck and envy you on that :) I have a sheriton super 10'' wich was a good quality copy of a myford.im building a similar indexing head to yours for the bench drill at the moment,exellent results on your motor testing ,your making me do a rethink on delta winds :D ive' mainly concentrated on Y winds,I see from your profile that we have a bit in common, :) anyway my respects from down under,cheers Lez. :)

[DadHav]

Where do I start :) super presentation,I know from my own experience the hours you must be putting into each motor build :) like myself you grind your own bits/cutters,i love your collet chuck and envy you on that :) I have a sheriton super 10'' wich was a good quality copy of a myford.im building a similar indexing head to yours for the bench drill at the moment,exellent results on your motor testing ,your making me do a rethink on delta winds :D ive' mainly concentrated on Y winds,I see from your profile that we have a bit in common, :) anyway my respects from down under,cheers Lez. :)

OK, Thanks my friend. Keep an eye out for stuff in the local used machine equipment shops. I picked up that little indexer and a few collets for $25.00. Everything I make, usually has some sort of small diameter on it so that it can be used in a collet. Something to think about.
John

[Art Newland]

DadHav
WOWWEE!! Awesome!

[mike3976]

John H. You got some really beautyfull motors there, excellent craftsmanship!!!

[BrunswickOH]

I just rewound one of my doubles with 12 turns of 24g wire for a plane I'm building and I went with a full 10mm stator stack (why I don't know) what are the advantages or disadvantages of using a full 10mm stack on a GBx double instead of two stock stators?

Thanks,
Jim

[fly_boy99]

Jim-

I really don't think there is much difference besides with the 10mm stack you will have a slightly more dense iron area then stacking two single stators.

fb

[BrunswickOH]

My guess is that it probably just lowers the KV a little. My initial tests probably bare that out. I got just over 7A WOT with a TP2100 3's pack and a 9x5 HD prop this should let me easily use a 10x6 prop which is what I was going for.

Jim

[sgtdirt]

jim,
i'm gussing that this motor will go on the Attitude?

[jj1]

Jim, got 12T 0,58mm(0,53mm) GBx2,5 and it takes:

6,3A/10,0V or
7,3A/11,1V

using same 9x5HD prop.

-JJ

Edit wire thickness. 0,53mm without insulation.

[BrunswickOH]

Yea Jack, it's for the attitude.

jj, I'll get some firm numbers later but mine are probably close to yours.

Jim

[Daveairway]

deleted

[Ron van Sommeren]

Also can you get DYI kits for larger outrunner motors?...Like the E-Flite .46 and .60 size. www.high-torque.com

A list of outrunner manufacturers, kits too (mainly in English):
http://www.rclineforum.de/forum/thread.php?threadid=43664&sid=


Do-it-yourself motor homepages, manuals/tutorials, checks and tests in the first message of this motor builders tips and tricks thread. The checks and tests may save you from frying your controller. Thread is active, bookmark it for future refence and subscribe to it:
http://www.rcgroups.com/forums/showthread.php?t=240993

Vriendelijke groeten ;) Ron
• diy motor building tips & tricks (http://www.rcgroups.com/forums/showthread.php?t=240993)
• diy outrunner discussion group (http://www.yahoogroups.com/group/lrk-torquemax)
• int. E fly-in & diy outrunner meet (http://home.hetnet.nl/~ronvans/), June 25 2006, Nijmegen, the Netherlands

[jj1]

Yea Jack, it's for the attitude.

jj, I'll get some firm numbers later but mine are probably close to yours.

Jim


Got inspired to try something different on this motor. New windings or...
Connected it to delta (similar as 7T wye) and it shows now some different character.

Kv 1500, Io(10V) 0,9A

3S(1700mAh) lipo and
HD8040 730g(26oz) thrust at 14,5A,
HD9050 1100g(39oz) thrust at ~20A.

-JJ

[olmod]

Nice one jj1
very simlar to this one of mine,except this swings a bigger prop at a higher pitch speed.
GB 22mm stator double 11t x .56 x Y

no load 12900 rpm @11.5v @.7 amp.
no load 16500rpm@8v @.75amps
12 10x4x2 n45


APCe 7x5 @7.2v @10amps=432g=15.26oz.

3sp 11.2v

GWShd 9050 11.2 v @ 10.5 amps @8600 rpm =688.59g
=24.31 oz thrust.

gwshd 1060 11.1v @ 11.5 amps @7500 rpm = 705.52g
=24.91 oz thrust.

gwshd 1170 11v @ 15 amps @ 6000 rpm = 757.33g
26.74 oz thrust.

[BrunswickOH]

Just got some numbers on my 12 turns of 24g GBx double (10mm stator stack)

GWS 9x5HD prop
V= 11.3
A= 7.6
RPM= 7680

[jj1]

Jim, almoust same numbers than in my 12T Y. :)

Olmod, nice motor, is the second noload voltage supposed to be 14.8V?

How much airgap there is in your motors?
Mine is about 0.1mm.. had to slightly machine stator in lathe to make it turn :o

-JJ

[flarssen]

I have winded my 22,7/10mm 12T 0,56 parallel Y.
I will try 6 magnet poles and put it into an EDF.


Fred

[jj1]

I have winded my 22,7/10mm 12T 0,56 parallel Y.
I will try 6 magnet poles and put it into an EDF.
Fred

Fred, that would be a 'Big -screamer' ;)

BTW, getting quite exited of the delta conversion on that GB2,5 12T -motor.
Hooked a 12V gel battery on it and it pulls over 1kg(37oz) with HD8040.. :D


W U/V I/A prop rpm Static(g) Speed(km/h)

09 12,2 1,0 noload 19,3k ---
122 11,5 10,6 EP7035 16,3k 680 87
231 11,0 21,0 EP8040 13,7k 1050 87

Typed parameters into drive calculator that clearly shows the difference.

-JJ

[flarssen]

Fred, that would be a 'Big -screamer' ;)

-JJ
It sure is! Just finished it and tested it with 2S:
(No load)
7.05V
2,7A
33300 RPM :eek:

There where some vibrations, so I think I need to balance the can before trying 3S :).
Just discovered that the 3mm rotor adapter is useless. The angle between the shaft and the rotor is far from 90 degree :(

BTW it's this one: EDF (http://www.allerc.com/product_info.php?products_id=1554)

Fred

[landru]

...BTW, getting quite exited of the delta conversion on that GB2,5 12T -motor. Hooked a 12V gel battery on it and it pulls over 1kg(37oz) with HD8040...

Hi JJ,

What kind of magnets you're using in that motor? Judging by the low Io, I guess they may be 1mm thick.

Andrew

[olmod]

Jim, almoust same numbers than in my 12T Y. :)

Olmod, nice motor, is the second noload voltage supposed to be 14.8V?

How much airgap there is in your motors?
Mine is about 0.1mm.. had to slightly machine stator in lathe to make it turn :o

-JJ
yer a bit of a stuff up there :) i try to get and usually manage a .15mm gap. ;)

[olmod]

Not that im a wizz at reading those graphs (especially the german ones they confuse me)
it looks as tho delta wind for the high performance motors is the go :D
good work :D

[jj1]

Hi JJ,
What kind of magnets you're using in that motor? Judging by the low Io, I guess they may be 1mm thick.
Andrew

Magnets are 10x5x2mm N50 (12x)

Motor has a plastic bell.. :eek: wonder how long it will last... :rolleyes:

Thanks olmod :)

-JJ

[flarssen]

My 6 mag motor seems to have too much cogging. None of my ESC's are able to start it reliably. I first used a TowerPro 15A. On 2S it worked fine.
On 3S it started to misfire at half throttle. On the 4'th try the ESC went up in smoke:rolleyes:. I have now tried: CC10, Dymond 25A and Feigao 60A.
Only the Dymond is able to start it sometimes, but not with the fan rotor installed. Without the rotor, it goes all the way to WOT at 3S. I have not done any measurements on 3S, but according to the 2S results posted above, it should be around 50K RPM (sounds like 150K):eek:

How would adding 6 more magnets (12 magnets, 6 magnet poles) affect the cogging?
(magnets are 4 mm wide, current coverage is only 30%)
Other suggestions?

Fred

[olmod]

Fred you have to be carefull of how wide the pairs are, to wide and they the performance drops off and the motor just overheats ,i havent played around with them long enough to discover the optimum width in relation to the width of the stator heads.but i know others have tried pairs of 3 mm wide mags with success. ive often wondered if it would make much difference if you had a small gap between them also.

[ecologito]

My 6 mag motor seems to have too much cogging. None of my ESC's are able to start it reliably. I first used a TowerPro 15A. On 2S it worked fine.
On 3S it started to misfire at half throttle. On the 4'th try the ESC went up in smoke:rolleyes:. I have now tried: CC10, Dymond 25A and Feigao 60A.
Only the Dymond is able to start it sometimes, but not with the fan rotor installed. Without the rotor, it goes all the way to WOT at 3S. I have not done any measurements on 3S, but according to the 2S results posted above, it should be around 50K RPM (sounds like 150K):eek:

How would adding 6 more magnets (12 magnets, 6 magnet poles) affect the cogging?
(magnets are 4 mm wide, current coverage is only 30%)
Other suggestions?

Fred

For a good performace you should have a magnet coverage between 70 and 85%. more magnets doesen't seem to do any good or bad. Good luck

[INewton]

Fred you have to be carefull of how wide the pairs are, to wide and they the performance drops off and the motor just overheats ,i havent played around with them long enough to discover the optimum width in relation to the width of the stator heads.but i know others have tried pairs of 3 mm wide mags with success. ive often wondered if it would make much difference if you had a small gap between them also.

Pairs work better than a single large magnet at each pole. The main benefit of pairs is that the eddy currents in the magnets are significantly reduced when there is a insulating gap between the pair. This configuration lowers the temperature of the magnets and increases efficiency of the motor as well.

Newt

[latrans]

Pairs work better than a single large magnet at each pole. The main benefit of pairs is that the eddy currents in the magnets are significantly reduced when there is a insulating gap between the pair. This configuration lowers the temperature of the magnets and increases efficiency of the motor as well.

Newt


Newt,

Could elaborate on this idea a little bit. How are there eddy currents in the magnets? Do they actually get on their own and not just from radiant heat from the stator? What exactly do you mean by an "insulating gap"?

Do you have any data on this subject that you could share with us?

I'd appreciate any info that you have.

Adam

[INewton]

latrans ,

The magnets are in the path of magnetic flux which is changing even in the magnets. The magnets are conductive since they are mostly made of iron, and they are plated with nickel, another conductor.

So for the same reason the stator is laminated the magnets should be laminated, that is to minimize eddy currents. Using two magnets is a simple lamination.

You can also minimize the flux changes in the magnets by using much, much thicker magnets and increasing the air gap to maintain more constant flux (this is why one increases the air gap for high RPM PM motors).

For the best results, do both. I read a good paper on this, but I can't remember where I put it. It was one of the finite element analysis reports. I'll keep looking.

BTW, for the last few percent of efficiency gain, a laminated rotor is required, but added weight and complexity is the trade-off. I'm staying with the usual flux rings.

Newt

[Ron van Sommeren]

... So for the same reason the stator is laminated the magnets should be laminated, that is to minimize eddy currents ...They have to be laminated in the same direction as the stator iron. For that reason the rotors in www.lehner-motoren.de are built up from magnet discs. I don't think splitting the magnets in two would bring much, you would have to split them up in more smaller magnetstrips.

Vriendelijke groeten ;) Ron

[INewton]

Ron,

Actually the direction of lamination doesn't really matter as long as there is no circular current path. Using two half magnets (cut the long way) give you the biggest bang for the buck. Splitting them again only improves things half as much. :)

How many poles can you get on a circular disk magnet? For inrunners? :confused:

Newt

[Ron van Sommeren]

... http://media.putfile.com/Weapon-Motor ...John, I noticed on error in that video. In the intro it says " distributed lrk ABCABCABCABC". You probably meant 'extended cd-rom' instead of 'distributed lrk.

Vriendelijke groeten ;) Ron

[flarssen]

I added six more magnets (six pairs), and the cogging was reduced a lot. No more startup problems:).
But now I doubled the losses due to eddy current in magnets;).
If one had curved magnets in two different sizes (maybe 14/28 degrees) this theory could be tested by using 12 magnets or 12 pairs.

Fred

[Ron van Sommeren]

Because of the extra magnets, the magnets now almost touch another. Part of the flux flows directly from one magnet to it's neighbour instead of via the airgap between magnet and statortooth. Magnet flux does rise as steeply anymore during rotation, it's a gentler slope.

Vriendelijke groeten/med venlig hilssen ;) Ron

[INewton]

And flarssen,

If you're using an aluminum bearing tube, I'd change it for a Carbon one before I did anything else. ;) Those 14 degree magnets... Great idea :D And a little bigger air gap might also be nice for higher RPM.

Newt

[bz1mcr]

And flarssen,

If you're using an aluminum bearing tube, I'd change it for a Carbon one before I did anything else. ;) Those 14 degree magnets... Great idea :D And a little bigger air gap might also be nice for higher RPM.

Newt

Newt,
Do you have any data on motors with different airgaps and all other things constant. It seems to me that the best performing motors have always had low airgaps, even the relatively high speed ones. But, I have never seen any data where only the airgap was changed.


The use of Al bearing tubes is almost universal. Many builders who started out using carbon fiber have changed to Al. Do you have any data that shows carbon fiber has any advantages?
Don

[flarssen]

Don, I agree with you. If there where any major losses in magnets or bearing tubes, why do all the big manufacturers use single magnets and alu tubes??
I have used magnets in pair on several motors, but that was because I used flat magnets and wanted to minimize the gap between magnets and flux ring.
You have a lot of curved magnets. Maybe you could break some of them in half and do the test? :)

Fred

[ScubaSteve]

not to mention the fact that carbon fiber sucks as a heat sink.... err.. doesn't suck... err.. you know what i mean. long live aluminum:)

as far as this laminated magnet notion goes, i'm sure somewhere the theory is there, but i'm not convinced the eff increase is noticeably existent in motors our size, nor worth the exponential increase in cost associated with what was proposed.

Carbon fiber is just a "bling". Yes, the weight savings is tehre is you're replacing a substantial amount of alum with it, but if you're just talking about a bearing tube, go chase down and splatter a june bug with your plane and so much for that weight savings. ;)

[flarssen]

long live aluminum:)

Here you have a lot of it :).
Test results will follow soon.
The "airgap" between the bell and the EDF base is the same as between the stator and the magnets!

Fred

[INewton]

Guys--

What I do is turn the aluminum bearing tube down 2 mm and bore out the inside of a carbon tube so that the stator slides over the carbon tube and the carbon tube slides on the aluminum tube. The goal is to stop the eddy current losses in the aluminum bearing tube when the magnetic flux is very high. The very hot bearing tube is not from stator heat. :cool:

The two magnets per pole serve the same purpose (to reduce eddy current losses) but for the rotor instead. Again at high magnet flux (amplitude and change rate) causes the rotor get very hot (even when the rotor is just driven with a hand held grinder with no current flowing in the motor). Splitting the magnets reduces the heating. ;)

The less heating - the more power goes into the prop and the higher the power level the motor can operate at. :D

The split magnets were something that Honda came up with for their new hybrids.

Don, the air gap is increased to reduce the magnetic field. Reducing the magnetic field is the usual practice with field wound DC motors when increasing the speed (5k -> 30k RPM). With BLPM motors you must pick the speed of operation since the magnetics are fixed. That is, a high RPM motor, 20k RPM, has much different magnetic power/loss requirements than running the motor at 6k RPM. :)

Newt

[flarssen]

OK, here are the no load values for six magnet pairs (fully charged lipos and balanced bell):
7.55V - 3.0A - 32460 RPM
11.60V - 4.3A - 50640 RPM

Compared to the result in post #47 (single magnets); more power, less RPM.

Fred

[INewton]

Fred,

Going from 6 to 12 magnets and only drawing a bit more no load current is quite good! :D Put a fan on and lets see the performance gain...

[bz1mcr]

OK, here are the no load values for six magnet pairs (fully charged lipos and balanced bell):
7.55V - 3.0A - 32460 RPM
11.60V - 4.3A - 50640 RPM

Compared to the result in post #47 (single magnets); more power, less RPM.

Fred
First an most important, 50K+ with a plastic endbell!! Please keep a strong scatter shield between that thing and any personnel.

Second, the increase in Io was very small considering the test voltage was up. It's even possible Io went down. Going from 6 poles 6 magnets to 6 pols 12 magnet did not change much. The Kv apperars slightly lower which is what should happen with stronger magnets. You doubled the strength and width of the magnet poles and yet the changes appear very small.

You said it improved power but you only quoted no load data? What makes you say the power increased? I hope you can provide some loaded data to complete the picture.
Don

[flarssen]

First an most important, 50K+ with a plastic endbell!! Please keep a strong scatter shield between that thing and any personnel.
There is no plastic there except for the fan housing. It's the well known GBx bell.


Second, the increase in Io was very small considering the test voltage was up. It's even possible Io went down. Going from 6 poles 6 magnets to 6 pols 12 magnet did not change much. The Kv apperars slightly lower which is what should happen with stronger magnets. You doubled the strength and width of the magnet poles and yet the changes appear very small.

You said it improved power but you only quoted no load data? What makes you say the power increased? I hope you can provide some loaded data to complete the picture.
Voltage increased by 7%, Io increased by 11%, RPM went down by 2.5%.
I was referring to input power.

I used a well known magnet spacer to measure RPM :). I made some paper into a tube and inserted it between the shaft and the spacer. I also use this method when installing magnets in GBx or Komodo bells.


Fred

[Ron van Sommeren]

OK, here are the no load values for six magnet pairs (fully charged lipos and balanced bell):
7.55V - 3.0A - 32460 RPM
11.60V - 4.3A - 50640 RPM... With 6 magnetpoles, your controller 'sees' (is operating for) 3 times that rpm: 151.920rpm. Keep an eye on the controllers max rpm, it is specified for two magnetpole motors.

Prettig weekend ;) Ron

[flarssen]

The rotor is badly aligned with the rotor adapter also, so there is a lot of vibration. I managed to get some measurements on 2S but my lipos is not able to handle the currents.
The values under load represents running the fan in both directions. I have no other suitable loads to put on.
I also tried 3S and got 30A. No voltage or RPM readings.
The efficiency seems low.
I will try to fix the rotor before doing more tests.

Fred

[bz1mcr]

...

I used a well known magnet spacer to measure RPM :). I made some paper into a tube and inserted it between the shaft and the spacer. I also use this method when installing magnets in GBx or Komodo bells.


Fred

Congratulations, that is a very creative use for a magnet spacer. I did not know it was such a universal tool. :D
Don

[reptilerick]

=======

[INewton]

The rotor is badly aligned with the rotor adapter also, so there is a lot of vibration. I managed to get some measurements on 2S but my lipos is not able to handle the currents.
The values under load represents running the fan in both directions. I have no other suitable loads to put on.
I also tried 3S and got 30A. No voltage or RPM readings.
The efficiency seems low.
I will try to fix the rotor before doing more tests.

Fred

flarssen,

How's the motor working with the paired magnets when driving the EDF? :confused:

Any conclusions on the value of 'paired' magnets for 6 pole operation? :)

Newt

[Art Newland]

Here's my latest. GBL 22.7mm stators X 10mm.
some video;
http://www.zippyvideos.com/6955856693576116/dw_7mm_bearings/

[mike3976]

Here is a few pic's of mine
five stator stack GB 25mm stator
microdan 2510 can
10x4x2 N50mags
34 0z thrust on 3-S

[flarssen]

flarssen,
How's the motor working with the paired magnets when driving the EDF? :confused:

Any conclusions on the value of 'paired' magnets for 6 pole operation? :)
Newt

As mentioned earlier, less cogging, easier startup and less noise.

I got no measurements with load for single magnets since none of my ESC's where able to start it with the fan on.

Fred

[peterp1964]

After alot of reading through these here threads, alot of false starts (shorts,
can/wire rubs, etc., etc.), I managed the following (did this as a practice
motor build before I attack Don's 22.7 Strong kit with 24 awg):

20 mm stator from cdrom, with stock bushing, Don's firewall mount,
Don's wire terminator, 26 awg, 15 turns (just couldn't get anymore in
there), Don's curved magnets (1.5 mm thick), and Don's stock can with
prop saver soldered on. The shaft (stock from cdrom rails) just sits in the
stock bushing due to the magnetic attraction.

At half WOT it draws 5A on 2S, thrust will have to wait till the weekend (send
the wife away, and pull out the wood for making the stand). Also, there was no
can lift-off up to half WOT.

One thing I had to do is this: when I put on the can there was magnet rub,
so I slightly filed the stator (that's why it shines in the pics). I hope this
is not a problem; the air gap is now almost non-existent and there's no
magnet rub.

A question: I used thin CA for the magnets, should I now use medium CA
or epoxy to fill in the spaces between magnets ?

Thanks all for the great threads.

Peter

ps. No-prop WOT draw on freshly-charged 2S Lipo was 0.7 Amps.

[bz1mcr]

Peter,
Congratulations looks like a nice motor.
For what it is worth, my curved magnets are less than 1.5 mm radial thickness. They were made for stock GB 20 mm stators and cans. Apparently your salvage stator was just a touch bigger. That is why the fileing was necessary.

A note of caution: if you are getting 5A at 1/2 throttle you will, almost certianly, smoke that motor at WOT. 6-7 A is about tops for #26 wire. It sounds like your prop is too big. A GWS 8-4 DD prop is a nice choice for a 15 T motor on 2S. that should run 6-7 A at WOT.

Don

[peterp1964]

Thanks Don. Yes, the prop was the 9070 SF...so off it goes...btw, pair-wise on
the power leads I get 0.4 ohms for the resistance.

Do you think I should fill the magnet spacing with epoxy or medium CA ? I don't
have thick CA.

Peter

[Art Newland]

Curved magnets have a lot of surface area in contact with the bell, I've never had a problem with just thin CA holding them. I use thick CA if the magnets are flat, to fill the gap behind the magnet.

[bz1mcr]

Thanks Don. Yes, the prop was the 9070 SF...so off it goes...btw, pair-wise on
the power leads I get 0.4 ohms for the resistance.

Do you think I should fill the magnet spacing with epoxy or medium CA ? I don't
have thick CA.

Peter

I don't think anything more than the thin CA is needed to secure the magnets, but it won't hurt anything either. I used to use west system epoxy after the CA but I stopped doing that and have had no problems. It is wise to use fresh CA as it typically is very weak if over 8-9 months old and somtimes less. It is important to keep it cool and out of the sunlight to keep it fresh.

Don

[fly_boy99]

I'm surprised that Don didn't mention anything about Peters bearing setup. Those stock bearings are not that great and if you plan to tackle higher rpm setups then it's time for some boca bearings.

[BeavrdamElectric]

Some of my favorite motors have bushings in them - no problem.

Good Luck!

[peterp1964]

Hi guys, I was also surprised by the observed lack of fly-out of the
can/prop. The magnets are pretty strong (no pun intended) and it
requires some effort to pull the can out...also, the air gap is not visible
to the naked eye, but the ear verifies that there's no stator magnet rub,
(I stopped filing the stator as soon as the sound indicated no rub).

If you look at my pics you'll see the magnet edges are flush
with the bottom of the stator and this was accomplished by using a
steel washer (3mm ID, 4.5 mm OD, 1mm thickness) on the shaft between
the underside of the can and the top of the stator. Don's cans have the
shaft hole somewhat recessed with respect to the can's face. So there's really no
force applied to the bottom of the bushing by the shaft during operation.

I'll see what this motor can do on the thrust stand this weekend on various
props. My tests thus far were with the motor vertical (clamped to the side of the
table) maybe there will be fly-out when the motor is horizontal.

But I must confess that 15T of 26awg on 20mm stators is my limit. Hats off
for those who can put 17-20T of 26awg in such a small space :)

Peter

[bz1mcr]

Hi guys, I was also surprised by the observed lack of fly-out of the
can/prop. The magnets are pretty strong (no pun intended) and it
requires some effort to pull the can out...My tests thus far were with the motor vertical (clamped to the side of the
table) maybe there will be fly-out when the motor is horizontal.

... :)

Peter
Peter, the can will not be pulled off one of these motors by prop thrust. If no E-clip or other means of restraint are used the bell can sometimes move, as much as a mm, and that can cost you a few hundred RPM. But, It will not come off.
Don

[dbeamon]

sorry to sound stupid, but im a nubie to building motors but i realy want to learn, got my winding down but dont understand how i can fasen a GWS prop shaft in my bell??? could someone please help, dbeamon@wfubmc.edu

[latrans]

sorry to sound stupid, but im a nubie to building motors but i realy want to learn, got my winding down but dont understand how i can fasen a GWS prop shaft in my bell??? could someone please help, dbeamon@wfubmc.edu


Depends on your shaft if it is unthreaded then you can use either a prop saver or a collet adapter - if it is threaded then just use a couple of nuts and a washer.

Latrans

[peterp1964]

On 2S Lipo (voltage never dipped below 7.5 V) I got the following on the
BP thrust stand:

with no prop, at WOT it draws 0.7-0.75 Amps

with GWS 8060 prop:

Amps Thrust (oz.)
5 5.9
7.5 7.1 (kept it here for about 10 seconds each time)
10 8.1 (never exceeded a couple of seconds at this draw)

is this sort of linear relationship between draw and thrust common ?
Do you guys think these numbers reasonable for a 15T 20mm ?

Peter

[Art Newland]

On 2S Lipo (voltage never dipped below 7.5 V) I got the following on the
BP thrust stand:

with no prop, at WOT it draws 0.7-0.75 Amps

with GWS 8060 prop:

Amps Thrust (oz.)
5 5.9
7.5 7.1 (kept it here for about 10 seconds each time)
10 8.1 (never exceeded a couple of seconds at this draw)

is this sort of linear relationship between draw and thrust common ?
Do you guys think these numbers reasonable for a 15T 20mm ?

Peter
Sounds like a little too hot a wind for the 8x6. Better drop down to the 8x4, or better yet, rewind for 17-18 turns, should get your current draw down to 7-8 amps depending on battery.

[peterp1964]

Thanks Art,

here are some more data points on the 15T, 20mm, 26 awg:

on 8040 and 2S:

2.5 A----> 145 grams
5.0 A----> 229 grams
7.5 A----> 280 grams (this was WOT)

on 8040 and 3S:

2.5 A----> 155 grams
5.0 A----> 245 grams (didn't go higher on 3S)

on 7060 and 2S:

2.5 A----> 110 grams
5.0 A----> 175 grams
7.5 A----> 210 grams

on 7060 and 3S:

2.5 A----> 133 grams
5.0 A----> 174 grams
7.5 A----> 242 grams

on 6050 and 2S:

2.5 A----> 114 grams
5.0 A----> 173 grams
6.5 A----> 192 grams (this was WOT)

on 6050 and 3S:

2.5 A----> 128 grams
5.0 A----> 188 grams
7.5 A----> 236 grams

Opinions ? Please feel free to criticize :eek:

The weight of this motor+prop+propsaver+winding terminator+
wires+dean's 3-pin male comes in at 34 grams...I'm thinking of
putting this on my Pico TM with the 8040 to get more prop clearance
for "better" ROGs...

Peter

[Ron H]

2s and the 8040 looks good for a TM. 7.5a may be a bit high, but it's unlikely you will need or want to fly at WOT for more than a few seconds. 8ozAUW is about right for a TM, so you should get 1:1 thrust:weight at around 5 amps. At 2.5a, your motor is stronger than an IPS, so average amp draw during flight should be fairly low. Might be a good idea to beef up the wings a bit before trying a high throttle loop.

[Art Newland]

You might want to give the GWS 7x3.5 HD prop a try on 3S too.

[peterp1964]

Added in Edit: Art, I can read your mind :eek: ...is this because
of cdrom addiction ?

--------------------------------------------------------------------------

Thanks for the info Ron...I will definitely replace my present
IPS-C (with feigao) with this motor.

here's the final set of data with 6/7 in props and different
pitch:

on 7035 and 2S:

2.5 A----> 127 grams
5.0 A----> 223 grams (this was WOT)

on 7035 and 3S:

2.5 A----> 155 grams
5.0 A----> 260 grams
7.5 A----> 326 grams

on 6030 and 2S:

2.5 A----> 123 grams
4.2 A----> 188 grams (this was WOT)

on 6030 and 3S:

2.5 A----> 150 grams
5.0 A----> 245 grams
7.5 A----> 318 grams

Peter

ps. Once some new Strong parts arrive I'll be putting together a
17T (managed to wind a 20mm stock stator, see pic, not very
pretty :) ) and then I'll redo these props on 2S and 3S for us
newbies.

[Ron H]

Now you need a CF spar and/or a gentle touch with the left thumb.

[peterp1964]

Now you need a CF spar and/or a gentle touch with the left thumb.

:D

Btw, I tried some APC props...what a joke ! these things are way too
unbalanced...also, the GWS 6030 at 7.5 A on 3S made the "whoa" sound
introduced to these boards by E-Challenged.

Peter

[bz1mcr]

Peter,
I can tell you are having fun! That's what this hobby is all about. I am glad STRONG parts has a place in it.

Thanks for sharing your results and experience by posting.
Don

EDIT, PS the "center hole" of APC props is not on center. The counter bore that the plastic inserts fit in is on center. Unfortunately the the wobbly propadapter does not fit APC props well (even when the plastic insert is used). If you want to run APC's I suggest the plain propsaver (a wobbbly with the "wobbly tip" cut off) or I can put a shoulder on a propsaver to fit the APC counter bore. The props are not normally too far out of balanced if they are well centered when mounted.