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        LRK and other larger homemade brushless motors: Part 2

#1 Mr DIY Sep 01, 2004 12:47 AM

LRK and other larger homemade brushless motors: Part 2
 
Original Thread can be found here.

First Page
http://www.rcgroups.com/forums/showt...8&page=1&pp=15
Last Page
http://www.rcgroups.com/forums/show...8&goto=lastpost
Brian

edit: last page link changed as per Ron's input. :)

#2 arx_n_sparx Sep 01, 2004 12:56 AM

First and last page is a good idea, MR DIY. I never thought of that one.

Brad

#3 Mr DIY Sep 01, 2004 01:49 AM

1 Attachment(s)
Phil

With regard to stator thickness, I have a rather big motor that I want to make. Posted a pic of stators some time back in part 1 of this thread. Its stator blades are 0.5mm thick.
I have also had some blades made for me that are 0.2mm thick … which is thin.
My problem though is to insulate them.. which leads to my thinking .. the thinner the stator blade, the more insulating material is being formed in stator stack which I suspect is not good. How you going to insulate yours? I see you gave a hint to say you have that sorted out?



Eljimbo posted

Quote:

Brian, the reference to grand poobah means Ron Van the moderator of this thread. Your work and drawings are magnificent. Thanks for your hard work.
Have you visited the Yahoo groups LRK site? I found this there.
Fisrtly, with what’s being going on, I was starting to give up. I am glad we now sorted this lot out.

As for the Yahoo groups LRK group, I did sign up with them quite a while back and followed all the emails. I even dug into the files/download section looking for the information I was trying to sort out here. Never found anything good. Will get to your pic shortly though.

Quote:

There is a lack of clear information regarding the (Y) hookup. I have seen dozens of drawings of "Delta" all over the web . None showing (Y).
Exactly what I trying to say all along. The only reference to a star hookup is in the distributed winding that Ron has posted from time to time. When I posted my first enquiry into the Stare/Wye, I had not noted that diagram. It could have saved me a lot of time.

What I would find interesting is… how many people have hooked up a Star wind for LRK incorrectly and don’t even know it. The motor will run, but it will work better when connected properly.

As for diagram posted, I find it difficult to follow. The list of right hand side does not tie up properly with stat or delta connection. If however, I draw a delta diagram and assign numbers in the linking order as per the table at bottom for delta …. then change wiring for star, it can work out correctly. I would like to see a proper diagram though. The pic alone is far too confusing for anybody building a first LRK motor.

As for doing a drawing for a proper Star/Wye hookup … I can do that.

arx_n_sparx

Your post 577 looks like the delta distributed wind.

Brian

#4 olmod Sep 01, 2004 02:35 AM

re insulating
 
quote..My problem though is to insulate them..

We used to punch out laminations and then they would go through a phospating solution,wich when rinsed and dried left a whitish look to them ,i have seen since a very thin laquerlike coating used on more modern laminations tho' ,some rust removers contain phosporic acid and probably would do the same job, IMHO.

#5 Mr DIY Sep 01, 2004 02:57 AM

Olmod ... I was thinking about the laquer type of insulation, but not sure how well it would work. There must be a better way that is can be done at home.

As for phosporic acid, will this do the trick on it own? Might be able to get some of it at work.
Would I just dip/rince and let dry as you have indicated?

#6 Happy|Harry Sep 01, 2004 03:08 AM

Quote:

Originally Posted by Mr DIY
Phil

With regard to stator thickness, I have a rather big motor that I want to make. Posted a pic of stators some time back in part 1 of this thread. Its stator blades are 0.5mm thick.
I have also had some blades made for me that are 0.2mm thick … which is thin.
My problem though is to insulate them.. which leads to my thinking .. the thinner the stator blade, the more insulating material is being formed in stator stack which I suspect is not good. How you going to insulate yours? I see you gave a hint to say you have that sorted out?

Brian

i can't really say too much yet as it's a top secret project ;), but the material is chosen is polycore, its classed as a low silicon, low loss electrical steel, no grain orientated and annealed, and the coating is c5 which is an inorganic varnish. i'll be sure to post more details when i can, and trust me you guy's will like it :D

phil

#7 max.ferra Sep 01, 2004 04:56 AM

Quote:

Originally Posted by Mr DIY

What I would find interesting is… how many people have hooked up a Star wind for LRK incorrectly and don’t even know it. The motor will run, but it will work better when connected properly.

Uh? Never been able to run a LRK motor not properly connected...

Quote:

Originally Posted by Mr DIY

As for diagram posted, I find it difficult to follow. The list of right hand side does not tie up properly with stat or delta connection. If however, I draw a delta diagram and assign numbers in the linking order as per the table at bottom for delta …. then change wiring for star, it can work out correctly. I would like to see a proper diagram though. The pic alone is far too confusing for anybody building a first LRK motor.

Brian

The idea of using the MPX connectors, and the picture you posted, is mine.
The pic shows a way to switch between star and delta connection, no matter if the motor is a normal CD-Rom, an LRK or whatever you built :-)
Obviuously it's insufficient to build a first LRK motor without any winding diagram (this last one is strongly dependent on the motor type!!!

Max

#8 olmod Sep 01, 2004 05:40 AM

quote ,As for phosporic acid, will this do the trick on it own? Might be able to get some of it at work.
Would I just dip/rince and let dry as you have indicated?

As i remember it was a low % of acid with water adjusted with a hydrometer,but if you try a few plates and you end up with a whitish look to them when dry, stack them together and with a ohm meter lightly touch the propes one on each side of the stack and if you dont have continuity your in business.

#9 Ron van Sommeren Sep 01, 2004 06:08 AM

Better last page of Part I:
http://www.rcgroups.com/forums/showt...&goto=lastpost :D

#10 Mr DIY Sep 01, 2004 06:12 AM

olmod ... thanx If I can get acid, I will give it a try.

max.ferra

Did not know that was your drawing. Certainly a great idea though. I might do something similar. Hell why not. :cool:

Is it possible to provide details of how the coils are positioned. For example, show a delta schematic with your numbers against each winding so somebody could make sense of everything by just looking at the hookups you listed? I found your table listing of the phases confusing. It may be just me though, although I doubt it.

As for running a Star hookup incorrectly, I did struggled to start my motor, but once running, it runs without problem. It depends very much on the controller as well though. I have averaging routines built into my software that would have averaged out the inconsistant BEMF signal and still run the motor with too much fuss.

#11 arx_n_sparx Sep 01, 2004 07:03 AM

Quote:

Originally Posted by olmod
As i remember it was a low % of acid with water adjusted with a hydrometer,but if you try a few plates and you end up with a whitish look to them when dry, stack them together and with a ohm meter lightly touch the propes one on each side of the stack and if you dont have continuity your in business.

In the old days, they used to just put transformer laminations out into the yard and let them rust :eek: :p I'm serious. The ferric (or is it ferrous :confused: ) oxide (technical name would be *rust* :rolleyes: :p ) insulated the laminations. If you want to use '50's technology, then laquer them. I saw a post by someone (and I don't know who it was or I'd give them credit) who used just *one* of the laminations and a shot blast machine. He layed the lam on a piece of newspaper and *blew away* the un-needed paper. Put one of these pieces of newspaper between each lamination and you're set.

I guess a little epoxy or lacquer wouldn't hurt either :p :D

Brad.

A p.s. to MR DIY: I suspect you made a start where you should have had an end on your motor - that's why it's a bit cock-eyed. You can argue all you want, but like Ron says, you want the phases symmetrical. Just my 2¢ on this.

p.p.s. - have enjoyed your input on the BLDC controller - you are talking WAY above my head on this stuff. I'm just slowly picking my way through a programming course on PLC's, and it's enough to boggle my *little* mind. The PIC's are too far ahead in the future for me to even see them over the horizon..... :o

#12 Ron van Sommeren Sep 01, 2004 07:06 AM

I compiled/wrote some info on stator thickness:
http://groups.yahoo.com/group/lrk-to...x/message/5875

Groeten ;) Ron

#13 Mr DIY Sep 01, 2004 07:31 AM

Quote:

A p.s. to MR DIY: I suspect you made a start where you should have had an end on your motor - that's why it's a bit cock-eyed. You can argue all you want, but like Ron says, you want the phases symmetrical. Just my 2¢ on this.
Ok .. now I am lost. I am getting mixed responces. Some people give me the immpression I am correct and others not. Regards Rons remarks, I am not sure what he is saying or who he is agreeing with. I thought my pics solved all of this. I will now drop this subject once and for all.

Brian

#14 Dongledell Sep 01, 2004 08:29 AM

I'm just gonna wind the bloomin thing wye style as I *think* it's right, and if it works, I'll be happy, but keep quiet, and if it doens't, I'll keep going till it does :p seems easier than keeping track....

#15 olmod Sep 01, 2004 08:36 AM

lol
 
Quote ,In the old days, they used to just put transformer laminations out into the yard and let them rust ,

I was going to tell them about that Arcs but i thought they would laugh at me lol you are 100% correct tho'. :D


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