The "Civil disobedience" 10 step backwards 1 forward...

[dontsendbubbamail]

My 80-100

/Goethe

I just want to make sure I understand what got damaged by what. This is a picture of the results of you trying to remove the windings?

Bubba

 

[Goethe]

I just want to make sure I understand what got damaged by what. This is a picture of the results of you trying to remove the windings?

Bubba

Yes thats right.

I milled one side down to the stator core. And then I was going to poke the windings loose with a screw driver. But it´s more or less impossible! The windings are
stuck together rock solid!

/Goethe

 

[johnrobholmes]

You may have to use some heat and/ or solvent to get that mess loose. Put it into the oven at 200c for 30 minutes, then take a punch and hammer to it! That'll fix it! :lol:

 

[Goethe]

Ok thanx!

So heat seems to be the solution!

-Do you have any suggestion of solvent?

-No problem with the insulation between the laminations when applying solvent or heat?

/Goethe

 

[johnrobholmes]

The solvent will depend on the wire coating and epoxy used. You could try alcohol or MEK on a area to see if it softens. If it doesn't then it is time to try heat. 100c may soften it enough, it just depends on the crap they used to construct the motor.

There really shouldn't be insulation between lamination, only on the outer edges to prevent stator to wire shorts.

 

[Goethe]

Thanx John!

Now I'm getting a little more confident in rewinding the motor!

I thought all laminated stators had thin sheets of insulation between the laminations?


/Goethe

 

[johnrobholmes]

The laminations should be made of a silicon steel that is a bad conductor, thus negating the need for insulating coats.

 

[Goethe]

The laminations should be made of a silicon steel that is a bad conductor, thus negating the need for insulating coats.

Ok. Thanks for the info!

/Goethe

 

[liveforphysics]

The laminations should be made of a silicon steel that is a bad conductor, thus negating the need for insulating coats.

No.

If they weren't insulated from each other, why would you even bother to have lams?

Silicone steel is used to minimize eddy loss from the remaining side thickness of each lam by making it poorly conduct. Insulation is used between every lam in the stack to prevent it from just acting as a solid block, which would behave something like an eddy-current-dyno brake.

If you short a bunch of lams together, not only will the stator get very hot when running, but the motor will have a huge drop and efficiency, and even spinning it with your hand it can feel like it's filled with peanut butter or something.

 

[Goethe]

The laminations should be made of a silicon steel that is a bad conductor, thus negating the need for insulating coats.

No.

If they weren't insulated from each other, why would you even bother to have lams?

Silicone steel is used to minimize eddy loss from the remaining side thickness of each lam by making it poorly conduct. Insulation is used between every lam in the stack to prevent it from just acting as a solid block, which would behave something like an eddy-current-dyno brake.

If you short a bunch of lams together, not only will the stator get very hot when running, but the motor will have a huge drop and efficiency, and even spinning it with your hand it can feel like it's filled with peanut butter or something.

This was what I thought before. But I´m not an expert in motor construction. :?

If the laminations would have an insulating oxide layer then you probably could do it without insulation sheets. ?!

But! If there are insulation sheets of X material, would it not be a risk dipping the stator into some sort of solvent?

/Goethe

 

[liveforphysics]

"laminations must be insulated from one another. The simplest way to do this is to specify a surface insulation on the raw material. Silicon steels are available with several types of insulation:

•--C-0:
Also called bare, or oxide coated. This is a thin, tightly adherent oxide coating put on the material at the steel mill, or during the annealing process after stamping. This is the lowest cost insulation, but offers little resistance.
•--C-3:
Enamel or varnish coating which offers excellent insulation, but parts so coated cannot be annealed after stamping.
•--C-4:
An inorganic coating providing higher resistance than C-0, but which will withstand annealing temperatures.
•--C-5:
An improved inorganic coating similar to C-4 but with significantly higher resistance. It withstands annealing well in most cases. This is probably the best choice for most performance sensitive applications. The main drawback to C-5 is an increase in tool wear due to abrasiveness."


I THINK they use C-3 or C-4 on most RC motors, but I'm not certian.

 

[liveforphysics]

Are you sure you can't poke the copper out mechanically? I don't know if you have a press, but a simple press and a flat faced drift managed to drive out about 90% of the windings for me in a hurry, followed by a little scrape down with some solvent and a brush and my slots were clean.

I think Jeremy Harris did his with a solvent soak, followed by simply unwrapping them? (or am I confusing someone else's de-winding?)

 

[Goethe]

Thanx!

Good info about the steel qualities!
-Ever tried cutting your own laminations?
-Is stamping the way to go?


Poking the windings by hand is IMPOSSIBLE!
I have a drill/mill machine that I could try to press the windings off with. Maybe warm it a bit first with the warm air gun.


/Goethe

 

[Jeremy Harris]

Are you sure you can't poke the copper out mechanically? I don't know if you have a press, but a simple press and a flat faced drift managed to drive out about 90% of the windings for me in a hurry, followed by a little scrape down with some solvent and a brush and my slots were clean.

I think Jeremy Harris did his with a solvent soak, followed by simply unwrapping them? (or am I confusing someone else's de-winding?)

I tried a variety of solvents, but none really loosened things up much. In the end, I warmed the stator up (gently) with a hot air gun and managed to get the winding to unwind fairly cleanly. The thing to watch is to avoid damaging the insulating layer in the slots. This also softens slightly at high temperatures. I re-coated the ends of the slots on my rewound stator with a thin layer of epoxy resin, just to make double sure that there were no sharp edges to damage the wire insulation.

Jeremy

 

[liveforphysics]

Thanks for clarifying Jeremy.

 

[johnrobholmes]

Ah, I was under the impression that the lams themselves were just bad conductors, when in fact there is a sort of insulation used. I do know that one chunk of steel just heats up, thus why we need laminations. It is good to learn something new every day! Even if it is basics.


I use my drill press with a punch in the chuck for pressing bearings and such. Maybe you could do the same to press out the windings? You could also make a jig to drill out the windings without damaging the stator (hopefully)

 

[swbluto]

I personally found that the older HXT 130 kV motors had non-varnished windings, so it was pretty easy to unwind. The "3 kw" motors and below, though, I've found typically have a layer of varnish that makes it just a bit impossible to take off. I have no idea where I went wrong, but it seemed like the hot air gun didn't do much because the varnish still acted like solid glue.

 

[MitchJi]

Hi,

Nice clean build but no front brake . Please put a disc brake in front with an 8" rotor.

Is the small front 8t/9t sprocket noisy? If so you might want to go to something like a 12t/14t and #219 or #35 chain.

Another option would be more primary reduction with the belt and a larger front chain sprocket. Check with Miles for a European source or Pfeifer Industries to see if you can get a better price on pulleys and belts:
http://www.pfeiferindustries.com/index.html

I would HIGHLY recommend a White Industries Eno freewheel available from Sickbikeparts.com standard freewheels aren't going to cut it for long...

Why not use a freehub in the rear?

But I have gone in to a mode where the costs are falling in priority and the obesessive-urge-to-be-out-and-hammer-the-throttle goes up.

...-Does anybody have a replacement motor to sell/recommend?

Astroflight 3110, 8150 or 3220 ($400-$700). I'd get at least the 8150 (only $100 more than the 3120 and 50% more power). Check with Matt (he stocks 3110's and he might have some 3220's in stock also) and Astroflight directly:
http://www.astroflight.com/index.php?main_page=product_info&cPath=20&products_id=122
http://www.astroflight.com/index.php?main_page=product_info&cPath=4&products_id=197

I recommend the 3220. Check with Matt to see what he can do for you and the Astro site is listing a sale price on the 3220 (might be out of date but worth an email to check):
http://www.astroflight.com/index.php?main_page=product_info&cPath=9&products_id=123

3220 Astro Brushless Motor,ON SALE
$650.00
NEW 3 inch ASTRO Brushless Motor
Order one today and we will make it and ship in about 1 week! USUALLY Priced at $799.00ea
One may use a high voltage controller like the Castle Creations HV85 or HV110
LET US MAKE A CUSTOM MOTOR FOR YOU! EMAIL YOUR SPECS AND WE WILL GIVE YOU A QUOTE!

But I have gone in to a mode where the costs are falling in priority and the obesessive-urge-to-be-out-and-hammer-the-throttle goes up.

I want to keep freewheel out of this build, does this leave me with only the sensored controller option?

If costs are not really a priority one of these should work (send them an email):
In case you don't speak German:
http://translate.google.com/transla...istungssteller.de/&sl=de&tl=en&hl=en&ie=UTF-8
http://www.sinusleistungssteller.de/index.html

SLS-42-110 ....................... ab EUR 599,-- (EUR 503,36 zzgl. MwSt.) Lieferzeit auf Anfrage
SLS-42-220 ....................... ab EUR 780,30 (EUR 655,71 zzgl. MwSt.) Lieferzeit auf Anfrage

SLS-60-100 ....................... ab EUR 659,-- (EUR 553,78 zzgl. MwSt.) Lieferzeit auf Anfrage
SLS-60-200 ....................... ab EUR 850,30 (EUR 714,54 zzgl. MwSt.) Lieferzeit auf Anfrage
SLS-60-300!!! ................... in Entwicklung

(SLS-XX-YYY: XX = max. DC-Eingangsspannung [V]; YYY = max. AC-Motorstrom [A,eff])

The Amp ratings are AC, add about 15% for DC so the SLS-60-100 is 60V 130 DC Amps or 6,900w.

More info here:
http://www.rcgroups.com/forums/showthread.php?t=788065

These controllers don't use block-commutation but sinus-currrent-control. Higher motor efficiency, lower torque ripple, lower noise, no current spikes between controller and battery:

 

[liveforphysics]

The sinus controller would be a really bad choice for an Astro, as it's a trapezoidal BEMF motor from it's shared-pole winding layout. The idea behind a sine controller is to use it if it matches the motor BEMF if you want more quiet operation.

Likewise, those sinus controllers would have even lower power limits than an equivalent FET stage switching a trapezoidal pattern, something like 30% lower. And this controller is going to have the same starting problems (can only sniff BEMF to sequence commutation), and in steady state high power applications that all the other RC controllers have with it's SMT fets. This one will just cost a lot more each time they pop.

 

[Goethe]

Ok. At last I got these freaking windings of the stator!
It took me 5 hours and the use of much more force then I wanted to. I really don´t like doing things like this, but nothing else worked.
The outer lams got a little bit bent, but I think I can epoxy them in to the right position again.

-What would be the next thing to do with the stator before winding it?
-Could I use epoxy for insulation? Or is it only the green stuff the should be used?

Nice clean build but no front brake . Please put a disc brake in front with an 8" rotor.

Thanx! I will put a V-brake on the front also, the braking power is great! Disc can look cool but I think it look better with V-brake on this bike.

Is the small front 8t/9t sprocket noisy? If so you might want to go to something like a 12t/14t and #219 or #35 chain.

It´s a little bit noisy. When I rewind the motor I will lower the kv a bit and go up a couple of teeth on the front sprocket.

Another option would be more primary reduction with the belt and a larger front chain sprocket. Check with Miles for a European source or Pfeifer Industries to see if you can get a better price on pulleys and belts:
http://www.pfeiferindustries.com/index.html

Perfect! I really need a better/cheaper alternative for drive train parts!

I would HIGHLY recommend a White Industries Eno freewheel available from Sickbikeparts.com standard freewheels aren't going to cut it for long...

Why not use a freehub in the rear?

Yes. I have begun to change my opinion to freewheel on this bike. If I stick with the CC controller it's definite that I go for some sort of freewheel.
If my 6 FET sensored controller turns out to work good I think I won't.

Astroflight 3110, 8150 or 3220 ($400-$700). I'd get at least the 8150 (only $100 more than the 3120 and 50% more power). Check with Matt (he stocks 3110's and he might have some 3220's in stock also) and Astroflight directly:

I recommend the 3220. Check with Matt to see what he can do for you and the Astro site is listing a sale price on the 3220 (might be out of date but worth an email to check):

I spoked with Matt and the 3210 and 3220 is 2 months away. It´s a little bit to long wait for me. The 8150 could be an option.
Anyway, the Astro motors seems like good stuff and I´m very keen on trying these on projects later on!


Mitch and LFP,

I think even if sinusoidal controllers primarily is for sinusoidal BEMF motors, they would work with trapetzoid BEMF also. The difference in commutation would be an increasing -> decreasing DCY with sinusoidal and fixed DCY with trapetzoid.
I think the large current spikes at the first pulses in trapetzoid commutation is reduced with sinusoidal where the first pulses would be at much lower DCY.

But anyway, the SLS controller seems like an very expensive option with a lot of uncertainties in use of this.
Even I have an economic upper limit! :wink:


/Goethe

 

[MitchJi]

Hi Goethe,

Astroflight 3110, 8150 or 3220 ($400-$700). I'd get at least the 8150 (only $100 more than the 3120 and 50% more power). Check with Matt (he stocks 3110's and he might have some 3220's in stock also) and Astroflight directly:

I spoked with Matt and the 3210 and 3220 is 2 months away. It´s a little bit to long wait for me. The 8150 could be an option.

Their site is probably out of date but it might be worth checking with Astro directly (pretty easy to send an email) given that they list a one week shipping time:
http://www.astroflight.com/index.php?main_page=product_info&cPath=9&products_id=123

3220 Astro Brushless Motor,ON SALE
$650.00
NEW 3 inch ASTRO Brushless Motor
Order one today and we will make it and ship in about 1 week!

 

[Goethe]

Hi Goethe,

Astroflight 3110, 8150 or 3220 ($400-$700). I'd get at least the 8150 (only $100 more than the 3120 and 50% more power). Check with Matt (he stocks 3110's and he might have some 3220's in stock also) and Astroflight directly:

I spoked with Matt and the 3210 and 3220 is 2 months away. It´s a little bit to long wait for me. The 8150 could be an option.

Their site is probably out of date but it might be worth checking with Astro directly (pretty easy to send an email) given that they list a one week shipping time:
http://www.astroflight.com/index.php?main_page=product_info&cPath=9&products_id=123

3220 Astro Brushless Motor,ON SALE
$650.00
NEW 3 inch ASTRO Brushless Motor
Order one today and we will make it and ship in about 1 week!

Thanks Mitch!

Now when the windings are gone I will rewind and put Halls on the Turnigy.


/Goethe