| 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:
- rpm
- 0 hp
- 0 ph
- 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
- Pole
- 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"
- mags total between O.D. of all 8 mags 4.875" = 4 7/8"
- 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
- magnets per pole
- magnets in all
- /2" x 3/8" Neo round rare earth mags
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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.
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I'm going to put up the next part of this shortly with the readings that we took. |
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