Post Mortem

[Phssthpok]

Well, I finally got the powerhead on the wind-genny torn apart. Although the bearings were indeed toast, they were still free spinning.

Turns out the problem was rust related. Specifically rust getting under the magnets and busting them loose from the housing.

Final tally:

Two busted/free floating magnets: http://i2.photobucket.com/albums/y32/Phssthpok/generator/windmill/genny031.jpg

And one free floating whole magnet (seen here propping up the housing): http://i2.photobucket.com/albums/y32/Phssthpok/generator/windmill/genny030.jpg

In addidtion, while the four brushes seemed to have a fair bit of life left in them, I'm not sure the same can be said for the commutator. Quite a bit of wear here: http://i2.photobucket.com/albums/y32/Phssthpok/generator/windmill/genny032.jpg

Top that off with two of the housing bolts shearing off when I disassembled the powerhead, and I'm not sure if this thing is worth rebuilding.

I got to thinking though....if I can replace these magnets with Neo's perhaps I can get this thing to REALLY put out some power.

I'm going to go shop Wondermagnet for a bit. (Insert evil grin)

[Phssthpok]

Well, phooey! FF isn't listing the size/shape I need. Wonder if the Dans can 'special order' some?

I'm not really sure where else to look, but if you folks wanna help me hunt, here's the specs:

5. /16" thick
   
2. 1/16" wide
   
1. 7/8" long if I use the original double magnet set-up, 4 1/4" long if I decide to go for one long magnet (which I'd like to do)
   
   

Arched at 3 11/16" outer diameter.

[willib]

Do you think some long skinny mags will work?

these are 4" long by 1/2" wide by 1/4" , and magnetized through the 1/4" .

depending on the origional gap it might work ... and they are a little pricy for sure

http://www.otherpower.com/images/scimages/2965/mags1.JPG

[mowind]

Check with this seller. He special ordered  some of these for me  

http://cgi.ebay.com/4-CURVED-SKEWED-ANTI-COG-WIND-TURBINE-GENERATOR-MAGNETS_W0QQitemZ260023448963QQi
hZ016QQcategoryZ42907QQcmdZViewItem

Mowind

[RP]

Those magnets were probably ferrites like an Ametek.  I think TomW did some testing with replacement Neos in an Ametek and was not impressed with results.  As I recall there was a question as to whether the armature was saturated already with the standard ones.

Here's the argument if you're interested:

http://www.fieldlines.com/story/2006/7/31/142713/242

[stephent]

think "superglue" and fix what ya got.

Also think about some weather proofing.

[elvin1949]

 Seems to me i recall  Nothing to Lose had

some arc mags about that size.

Not sure but worth checking.Good price to.

later

elvin

[Flux]

Forget superglue, it is absolutely useless for anything but paper, I don't know how they sell it and stay in business.

To stick those magnets you need a structural acrylic adhesive such as Loctite multibond 330( may be Europe only). Others have posted Loctite references here.

If you can find it Hugh Piggot posted a reference here recently to one of the best ones, probably in the discussion on magnet corrosion. Good epoxy will also do the job.

If you replace ceramic magnets with neo of the same size in that type of motor you will gain little but iron loss and cogging. You could possibly use thinner neos with a larger air gap but even that may do strange things with armature reaction on a dc machine. Use the original magnets if possible.

Flux

[dinges]

Loctite's support engineers recommended Loctite 326 to me for mounting nickel-coated magnets. Flux is right, superglue (cyanoacrylate) is absolutely useless for this purpose. Superglue has its uses beyond paper. Is great for glueing fingers to eachother.

I have opted for using epoxy to mount the magnets in my mini motor conversion.

[coldspot]

Phssthpok-

ntl's magnets

L= 1.75"

W= 1.25"

H= .25"

Also known as the # 29

[Phssthpok]

Well, I decided to try and get this thing cleaned up and back together using the old magnets, so I began removing the already loose magnets tonight.

No joy. This thing is dead as hell. One of the mags that broke in half also began to de-laminate. That is to say it began flaking apart in layers.

Combined with the busted housing bolts (rust) and the thoroughly toasted bearings, I'm going to declare this unit "not worth the effort" of rebuilding. At least not right now.

So that means I'm on the lookout for a new 4 pole DC servo motor that will accept the blade hub. I'll need a shaft 5/8" dia, and about 3" (if I want to fully seat the hub)

You folks have any suggestions on where I should look, and what search parameters I should use? I'm a metal worker by trade so if I need to modify/remake the mount/pivot for the powerhead, it's not really an issue. I kinsa like the idea of converting to a Piggot-style side furl set-up anyway.

Bear in mind this genny is not intended as a primary power source. I have an almost 1KW (and growing) solar array, and I was looking for a small wind genny as a companion. If I can get something that will give say 1-200 watts in a stiff breeze (just shy of a solid WIND) then I'll be happy.

[Phssthpok]

A quick search of E-bay netted me these two possibilities:

http://cgi.ebay.com/Dayton-electric-1-4-hp-motor-90V-DC_W0QQitemZ290027584037QQihZ019QQcategoryZ7140
0QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

http://cgi.ebay.com/dc-motor-1-4-hp-boston-gear_W0QQitemZ280025706359QQihZ018QQcategoryZ71400QQssPag
eNameZWDVWQQrdZ1QQcmdZViewItem

Obviously I'd be weather sealing either of these as best I could, but what I want to know is if I'm on the right track in selecting these two as possibilities.

[ghurd]

Might want to find out a recommended HP for those blades.

A 1/4 HP seems a little small to me, but I don't know.

I have a couple larger Daytons about like that in the garage, they work.

Turn smoothly, look sealed pretty well, etc.

G-

[Phssthpok]

One more question:

How can I determine just how much power (amps) I could expect from a PM motor when driven as a genny at a given RPM?  I see alot of refernces to amp ratings for the armatures.  Is this info I need or is it irrelevent since it relates to powercoming in, not going out.

Also...I found this unit fairly cheep:

http://cgi.ebay.com/Dumore-Permanent-Magnet-Motor-115VDC-1-4Hp-New_W0QQitemZ280029818645QQihZ018QQca
tegoryZ71400QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

It seems to be almost identical in size to the powerhead I pulled off. About 8" long x 4"OD, with a 5/8 shaft approx 3" long. Unfortunately I have no way of knowing what the rated speed of the old powerhead was...wait...It has 4 brushes.

4 brushes means four poles yes? That would make the old genny an 1800rpm motor, correct?

Hrmm...this one's a 36K unit... Hmm....

GAH!!!! I hate this 'knowing just enough to know I'm ignorant' feeling!

[ghurd]

"4 brushes means four poles yes? That would make the old genny an 1800rpm motor, correct?"

I don't think so. 4 poles & 1800RPM is for 60Hz AC.

I remember someone saying keep the amps at double the name plate or less. Sounds reasonable (safe) to me.

Remember watts = amps x amps x ohms.  1A and 10 ohms is 10W. 2A is 40W.

Just because it can make a lot more amps doesn't mean it'll do it without melting.

That one looks better to me, just because of the money if nothing else. :-)

I'd try to keep it below 5A.  Cutin at ~350 for 12V?  

Just a bad guess, it's probably too small for your blades.

G-