Rewind of a 5 kw Chinese wind generator

[Prad]

Hi ,
        I have been following this site and have been inspired to build a few axial turbines which are working great .
 Recently i bought a second hand non functional  5 Kw Chinese wind-turbine and trying to sort out the winding issues to start with .
  The stater is a 54 slot unit divided into 18 coils per phase , and the rotor consists of 16 magnets arranged in a north south config .
The original  winding was 25 turns of 21 SWG using 5 parallel wires .
 The stater was epoxied so getting much more information was difficult .
 I rewound the stater using 21 wires of 21 swg with 5 turns per coil to get an output of 50 volts 3 phase star formation .
 Now  i tried connecting 18 coils  start start  and the end end of the coils on the consecutive coils.but got a very low output on my test connection .
 I have created a drawing of the stater and rotor to understand as to where i am going wrong , which i am sharing with you so that i can get a better understanding of the problem .
 My other question is from which coil do i start each phase do as to get a 120 degree output .
 
 
   

[joestue]

16 magnets and 54 slots requires a rather complex two layer winding. but it does have a very high least common multiple and will have very low cogging torque, and rather respectable winding factor of 0.94.

what you probably have is a 16 pole 48 slot stator. (16 magnets)
or you have an 18 pole 54 slot stator. (18 magnets)
these systems require skewing the magnets or other fun and games to get the cogging torque lower because the least common multiple of 16 and 48 or 18 and 54 is 48 and 54 respectively.

but the winding layout is much simpler.
you have to remember to reverse the connections every other winding.

this site will show you all the winding layout options.
https://www.emetor.com/edit/windings/

[Prad]

Hi ,
       The stater is definitely  54 slots and 54 poles ,and the rotor has 16 magnets arranged in an alternate north south configuration .
 I tried the emetor table and could not make any headway .
  In this alternator the stater poles are skewed and has parallel magnets .
 I have seen this alternator working great on the original winding .
  I am posting a picture of the stater with the original  winding .
 I have rewound the stater with a considerable effort and am now spending many sleepless nights thinking about the connection method in order to match the 16 pole rotor and the 18 x 3 phase = 54 , coils .

[joestue]

click on the square that corresponds to the number of poles and slots you have and click on show winding layout.... http://imgur.com/HxiOIbV

I'm really not sure how you can get anywhere with a standard full pitch winding, what you have appears to be the standard coils for an 18 magnet, 54 slot generator.

[Prad]

Hi .you are right it is a difficult task and I may have to rewind the stater because I have counted the magnets again and again and they are 16 in number .
But the positive side is that I have found a site which gives a design for an unbalanced winding which is my only hope .
You can put the slots and no of magnets and get the data .http://www.bavaria-direct.co.za/scheme/calculator/

[Prad]

Hi.
Success at last I got the alternator going .it will be assembled and will be flying soon .
Will keep you posted .
I am greatful to Joestue for his help and support.

[joestue]

yeah i've never tried one of the fractional slot windings because the winding diagram made it appear you would need a mix of 3 slot and 4 slot windings, but as you figured out in the diagram you drew, you just had to reconnect the windings differently.

might be good to repost your drawing, the forum was reverted to a prior backup or somethign and some posts got deleted.

[Prad]

Oh
I thought that the admin found my drawing not appropriate so was delated .
 In case it is welcome it will be a pleasure .
 In fact my tests were much better than e xpected , but all that cutting and reconnects left the connecting leads pretty short and since the output may reach a 100 amps i am taking no chances and silver brazing all the interconnections .
 I had to brush my skills for the brazing job , but turned out ok , and am in the process of threading the coil leads and a little bit of varnish and i am ready to shut and install .
 

[JW]

He is right the forum lost like 20 posts when we recently changed our host. It would be great if you would repost your drawing.