3hp 3ph Conversion

[behoof]

We got this motor to convert basing it on Zubbly's 3 part conversion posts.

We bought this Baldor 3hp 3ph 4pole used motor off Ebay for $35.00USD + shipping. It is a:

1725. rpm
      
3. 0 hp
   
3. 0 ph
   
460. volt
     
     

TEFC

Face Mount

wt 50lbs


So on receiving it I opened up the Baldor and found the Y - Connection and clipped it and added 3 wires per Zubblies instructions here --> http://www.fieldlines.com/story/2004/8/13/191519/161. I was really pretty straight forward once getting in there and looking at it.





After adding the 3 wires, numbers 10, 11, & 12, and the necessary insulation to protect everything I closed it up, varnished it and baked it.





Next up was converting the stock armature from being an induction motor arm to a Permanent Magnet Alternator Armature by machining it and adding 128 1/2" x 3/8" Neodymium Iron Boron Magnets (NdFeB)(rare earth magnets).





Now we needed to make a map of how the magnets would be mounted on the machined armature inside an aluminum sleeve. Zubbly's posts had talked about using fiberglass as a magnet cage but we opted for the aluminum. I proceeded to get a small CAD program from the internet and made a drawing of the mag layout. To make this a bit shorter than it actually took to create the sleeve, let me just say that you REALLY need to measure about a dozen times and machine once, LOL. Anyway, what happened is that the CAD program when I input my degree angle measurement for the skew angle of the mags it came out differently than the input. I just trusted and went ahead with the machineing. Big mistake. I center punched, center drilled, drilled, then bored and then chamfered both in and out a total of 128 times for each operation. Then, I frequent the IRC channel quite a bit, Dinges called to my attention that based on an uploaded picture of my magnet map it was not angled correctly. Bad news but I went back to the drawing board and did it again and on rendering the new drawing I found it to be off also. Dinges did some math for me and I had to use some hit and miss angle numbers to get the CAD pgm to cooperate but I finally got a drawing that was at 4.04 degrees, the angle I needed.





This is a 36 stator slot motor so when we read the angle between two adjacent slots we come up with 4.04 degrees.




• 
  
  Specs on the conversion:

  
  3hp 3ph Baldor      Conversion Wind Generator   TEFC    Face Mount

  
  Information
  

  
  
  
  4. Pole
     
  36. segments in Stator
      
      
  
  Stator length                      4.750"
  
  Stator diameter I.D.                      3.983"

  
  Rewire per zubbly instruction for w/3 extra wires

  
  Turn armature down to                      3.551"
  
  Armature with mags on diameter                  3.926

  
  Make Aluminum Sleeve for magnet mount
  
  Sleeve O.D.                     3.820"
  
  Circumference                          12.0"
  
  Sleeve I.D.                       3.1735"

  
  Measurements for mags
  
  Skew Angle                       4.04degrees
  
  Total Size                     12" x 5"
  
  Across 8 mags center to center                  4.375"
  
  Across 4 mags center to center                  2.049"
  

  
  
  
  8. mags total between O.D. of all 8 mags      4.875" = 4 7/8"
     
  4. mags total between O.D. of all 4 mags             2.561"  = 2 9/16"
     
     
  
  Distance between 4 mags                     .187" = 3/16"
  
  Distance between total pole  32 mags         .437"  = 7/16"

  
  Magnets
  

  
  
  
  32. magnets per pole
      
  128. magnets in all
       
  1. /2" x 3/8" Neo round rare earth mags
     
     
  
  

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

Next we need to machine the armature down to allow the O.D. of the arm plus the neo-magnets to clear the stator windings and laminations by at least .025". As we machined the arm just as we got into the aluminum material it all seperated.

We chose to compress and TIG weld the lams back together and continue turning the arm down to the desired diameter which took 3 different welding sequences to arrive at the diameter. On the next conversion we do we plan to just machine a new armature rather than go through all this as it will be simpler.

The finished armature came out looking like this.

Now we have to make the aluminum cage or sleeve for the magnets. We did this by turning down a 4" x 3/4" wall 10" piece of 6061T6 aluminum tubing.

Then I cut out my CAD drawing and centered it on the finished aluminum tube and center punched all the 128 holes.

After center punching, I center drilled and bored then chamfered the 128 holes.

Centered the sleeve on the armature using paper of the thickness needed.

We then installed the magnets using Loctite cylinder adhesive and baked it in the oven over night at a very low temp to help the cure.

We next painted it with a VHT paint to help seal it and to add a little bit of protection when installing the arm in the case.

We then installed the arm in the case and torqued it all down and moved it to the lathe for testing.

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

I'm going to put up the next part of this shortly with the readings that we took.

[dalibor]

this is space technology :-)

way to go.thank you for sharing it with us.

[CreativePower]

Looks like a nice job - I hope it works well for you - what is the mill size that you are planning to hook up to it? What were the orientations of the magnets in each group setting (the 4x8 mag arrangements).

Thanks for sharing your efforts!

DF

[TomW]

behoof;

All that mean stuff I said to you on IRC, please disregard it. OK?

Tom

[dinges]

Tom, can I disregard all the mean stuff you said to me too ?

Behoof, looks very nice!

2 questions:

• the cage, did you turn the inside yourself too, or was it already to the correct dimension, as you used tube. In one of my conversions I got lucky and had aluminium tube that was of the correct inside diameter. Saved an awkward inside-turning job.
  
• why have you turned down the outside of the cage so much? It looks like you had plenty of material so that the magnets could have been entirely 'sunk' in the rotor. That way there would be no risk of damaging the nickel plating whilst inserting the rotor into the stator.
  
  

You are a more patient man than I am; after I had made my 3 hp conversion, using 'just' 40 holes/pockets for the magnets, I concluded that that was NOT the way I wanted to make larger conversions Considering that each hole needs to be centerpunched, pre-drilled (perhaps 2 pre-drill steps?) and drilled to final size, I estimate that you have drilled 256-384 holes (excluding the first try of the cage).

But it certainly looks like a work of art. Almost a shame that it will be out of view inside the motor.

Regards,

[behoof]

Peter,

Yes, I did turn both inside and outside.

My reasoning for leaving the mags sticking up a bit was to not have 'cups' that might be able to gather loose material over time inside the jenny. Probably not a concern but I felt it might be a bit more "self-cleaning" if exposed just a wee bit.

Well, you were close on the operations performed, LOL, let me see now:

center punching

center drilling

drilling for pilot on bore

boring to size

chamfer outer hole edge

chamfer inner hole edge

let's see now, hmmmm, that's 768 operations. And, oh yeah, lest I forget <grin> I ended up making 3 of them total. So, I guess the total ends up at 2304, oh my, so that's where the time went , Uggghhhh now that's some practice.

behoof

[TomW]

Sorry, Peter, anything said to you was spot on and intentional.

Anyway, hoof sure did us proud here.

Cheers.

TomW

[ghurd]

Very nice!

I like the photo of the laminations falling apart.  Can't recall anyone showing that before, though I have seen it enough in person.

Do you think the magnets sticking out will aid much in cooling?  The wind and the magnet placement would move some air... I think.

Will the internal fan be left in place?

The 2304 operations are physiologically better counted like the Chilton's manual for my truck, 3 steps to change the motor. Remove old motor, find replacement, install.

G-

[behoof]

ghurd,

When the lams fell apart I about jumped a foot, didn't expect it but like everything else, just deal with it.

Yes, I think the exposed ends of the mags will move some air at least they'll be exposed but like I told dinges, I was more concerned about catching foreign material.

Gotta tell you, I like your math a heck of a lot better than mine... yeah, that's it, you can make this arm in only 10 easy steps, LOL. I really like your math over mine.

[behoof]

ghurd,

Forgot to mention that yes, the internal fan will remain in place.

behoof

[joesfoundry]

So what were you able to get out of it?

[behoof]

joesfoundry,

Here's a link to the info...

http://www.fieldlines.com/story/2007/8/28/51444/7540

behoof

[tecker]

Nice Choice for a hawt should give a lot of bang for the buck . The bearings on those motors are tucked away nicely and the end caps sit in the motor frame steady . When you cut the Squriel cage away like that the segments let go every time . That's a pump motor really good work and a lot of lath time .