Treadmill motor, is this a good one?

[madlabs]

Hi All,

Found a good motor at the dump today from a treadmill, at least I hope so. Is this a good one?

Baldor Industrial Motor

HP 2.4,  RPM 2500, ARM Volts 130, Amps 21

I'd be using it on a 12V system.

Here's hoping! Thanks for the help!

Jonathan

[Rover]

...weird.. think I have the same one/or similar  mounted outside. Yes , it is a decent generator if you have the wind.

Search my previous posts....look for baldor... I have graphs and etc on it

[madlabs]

Rover,

I did look earlier and saw your posts. My main question is that my ARM volts are much higher than yours, 130V as opposed to 90V on yours. Any blade reccomends?

[taylorp035]

19 Rpm / volt.

2500/130*13v = 250 rpm cut in.

[madlabs]

The cut in RPMs look pretty good. Another question: The motor has a shaft at either end. On one end was a large flywheel, 8" diameter, 1" thick. Must way 20 pounds. can I use this as a hub? Or should I get another made?

Also, when I short the output, it gets harder to turn, but not real hard. I'm going to try to call Baldor and see if I can get any info.

Thanks for the help!

Jonathan

[taylorp035]

I bolted a plywood hub to my flywheel.  Don't mind the wire in this photo, that should never be repeated.

[madlabs]

Do you think it's a good thing to have all that flywheel weight? I just order a shaft coupler to weld a hub to, but if it is better to use the flywheel I can. Thoughts?

Just managed to do an open voltage test, got 12.2V @~300rpm. No actual RPM data, that is just what the drill is rated for. I'll set up a tach soon, but that seems a little low.

I love this board. Where else can you get info like this?

Jonathan

[taylorp035]

My windmills are designed to be removable from my pvc tower, so I definitely notice the extra weight.  I didn't remove mine because it was easier to just leave it there.

[Rover]

I would ditch the flywheel .. or find some other use for it. As far as blades.. mine seems happy with roughly 4.5' diameter set. I change them all the time as I test designs for the fun of it (this is a hobby/test bed mill).

If you are just getting into this ... try a set of pvc, lots of desigss on here for that (cheap to build), you'll soon get a feel for what kind of blade you need. Typically somehing fast, for a gen like yours.

[madlabs]

I am going to use PVC pipe, I just got a 12' length of 8" schedule 90 pipe. Ordered a shaft coupler and a buddy is going to weld the hub on it for me.  I'm trying to wade through all of the stuff on figuring out what length blade and angle and all of that. Any reccomends on good things to read, plans, calculators, considerations etc?

Thanks!

Jonathan

[Rover]

Please bear with me .   we have no idea if you have great wind, poor wind, sustained medium wind, turbulent wind , the heigHt at which you are going to mount etc.. (ses the variables involved?, I didn't when I started ... only 2-3 yrs ago, and I'm only mentioning a few) .

If you don't have the anenometers . ammeters,  (typically,no one does starting out)  etc... I'd find a trusted pvc blade design (yes on here or google, in the 4 ft range (diameter not each blade)), and watch your voltage,behaviour for impact (does it spin? if so does voltage go  up?)  . Do I have one to pass out.. no.. sorry... not taking that kind of risk .. too many variables you can blame me for later.

read and pick one..

[ghurd]

(Hey, Welcome back)

Woof's post about PVC blades is good.
I tried many variations, and those angles are about as good as it gets.  The more I deviate, the worse they work.
I have them figured at about 4.5TSR, but others have them figured at about 4TSR.

The flywheel weight won't hurt anything.
I would make sure the blades spin in the direction to keep it tight (they can be threaded left or right).
I would rather tack weld the flywheel to the shaft instead of make a new hub, but that's just me.

I think 4.5' dia is pushing the limit on PVC blades.

I have a feeling 5 PVC blades may be about the best, but have no way to accurately test them.
They are very forgiving, so anything close to good will work pretty well (not as well as good carved blades).

PVC blades bend back a lot.
Make sure there is a Lot more tower clearance than you think they need.
Tipping the motor back/up a bit helps too.  A few degrees makes quite a bit of extra clearance without losing any real swept area.
G-

[wooferhound]

It appears that my PVC pipe prop plans didn't make it over to the new FieldLines board
Use the largest diameter pipe you can find, 6 inches (15cm) minimum
Use 25-30 degrees for your Hub angle point and 7 degrees for the Tip angle point
Here is the picture . . .



and here is a calculator . . .
http://www.fieldlines.com/board/index.php/topic,142104.html

[klsmurf]

I made a set of PVC blades for my treadmill motor and they work good for starters. There's a picture here:http://fieldlines.com/board/index.php/topic,143789.0.html. I used 8" schedule 40 so they probably bend more than your sch.80. They are 3.5" at the root, taper up to 4.5" at 45 degrees, then down to 1.5" t the tip. 2' in length. They are pretty easy to make and you can shape them to resemble an airfoil fairly easily. Jigsaw, light touch with an angle grinder and a palm sander. Have fun!

[madlabs]

Rover, I won't hole you responsible for and carnage resulting from your blade design, so lay it on me!

Some more details on the project: I live off the grid, 1200aH, 12V battery bank, some solar and a lawnmower/ alternator setup I made. I do have ammeters etc. I'm no EE but I built my own power system here and my own power monitor/controller that does stuff like PWM the field coil on my alternator to control charge, stuff like that. I do have a anenometer, but is mounted at my old place, so I don't have any wind data. Guessing out of my you know what, I'd say that in the summer winds are rarely above 20-25 mph, in the winter we have a fair amount of 20-25 and  of course storms that go much higher. I was thinking of making a set of summer blades and a set of winter blades. No furling in the immediate future, at least until I see how viable wind power is for me. As for tower, I am planning on starting with a 20' tower and then upgrading to a 40'. I'm in a decent clearing, but there are some trees within 100' and the treeline (fairly short trees, 60' or so) is 300' away.

Woofer, I dug through a bunch of the posts related to blades. Unfortunately, a lot of the links are dead due to the board move. Do I really want 2 blades? My instinct says 3-5. You say 7 degrees at the tip, so it seems that where I locate the mounting bolts will dictate the blade angle, correct?
Ghurd, at 4.5" diameter, my blades would be 2.25'. Is that really about right? I know that smaller is faster, but then there is torque.

I'm away for a couple of days, but I'll be back to this thread after that.

[ghurd]

If the angles are off then they won't work worth a hoot.

I make mine individually.
The bolt holes line up with the center line / trailing edge.



I use a long piece of extruded AL angle stock to make the straight line.  Works very well.
Can get more blades out of a section with some planing.
Cut them a bit over sized in every way at first.  They kind of 'spring' and deform a bit in the first day or 2.  I like to make a lot of blanks while I am at it, then let them sit a while to get how they want to be, then I do the final cuts on a band saw, finish shaping and balancing on a bench top belt sander.

(Old crappy, semi-related, layout sketch for those interested http://www.fieldlines.com/images/scimages/2050/ValPVC2.gif )

Works for me!

The 4.5' max is related to how far they can bend back in a strong wind, and my fear of breaking one.  It was not a suggestion for length of your blades, but it may be a decent place to start?
I am not familiar with sch 90, but I know strong wind really bends back PVC blades.

I doubt you will get enough improvement to be worth changing blades for summer and winter.
Try to get cut in at about 7MPH and it'll work fine.
And expect to try several lengths before it works well.
G-

[madlabs]

Ghurd,

Lots of juicy information, thanks. Do you have some measurments for the picture so I can figure out some ratios? The schedule 80 is thick, like 9/16" thick.  Changing the blades summer/winter wasn't so much about performance as survival in high winds in the winter.

In the link the drawing shows a 4 blade prop. Should I do 3, 4, or 5 blades? I want to start cutting blanks today. I got some 1/8" wire rope, 340 lbs working load to rig my tower. I hope that will be ok, but I'm going to start another thread about my tower plans.

Jonathan

[ghurd]

Uh oh... You may think I know more about it than I do.
(I had my wood blades made by another member)   

Have a look at Rover's posts about his.  A good place to start anything like this is with any info about what worked, what did not, any why.

The ratios are built into the angles.
Length is not a factor to the design.  I used the same angles with 5 gallon pails, and they worked fine (until medium-strong wind bent the flimsy blades back).

(no laughing)
I set a squarely cut end on poster board (ie: 12 pack cardboard).
Which brings up the issue of squareness.  I only cut from one end, as square as I possibly can, leaving the other end factory square for reference.

I trace the OD, then draw the 7 and 25 degrees on the cardboard.
I put the pipe on the cardboard, and mark either 7 or 25 degrees on the proper end, with a super extra ultra fine Sharpie permanent marker.
I measure the OD of each as close as I can, then use that size to mark the other blades.

Being off from the plans from perfect 1/32" is not usually a problem, as long as all the blades are actually the same.
For balancing, I start taking off some of the square part of the root, maybe some off the hub (my plywood hubs usually end up egg-shaped), then I shorten the heavy one.
I had some that were over 1.5" difference from the longest to the shortest after balancing, and they ran smooth as silk.

That 4 blade sketch was for a stepper motor question.  Tiny 15~18" diameter stuff.  The square at the center kept the blades from twisting on the single screw.  It allowed me to change out blades for different motors, etc.

I just keep trying different set ups until satisfied.  Don't cut up blades to make the new blades, because eventually you will end up making more blades like the ones that were cut up.
If it was mine, I'd probably start with 5 blades, about 4' diameter.  And 5 blades 4.5' diameter.  And I'd expect to make a lot of changes as things went along, because I always do.

I believe 4 blades is generally frowned upon.  Even number (2, 4) of blades can create issues.  3 or 5 is the 'usual' number.
Pipe blades are slow compared to typical carved wood blades, so I think 5 is usually good.
I believe after cut in that motor will create some pretty serious drag, and 5 PVC blades may get past it fine.

And if I needed 5 blades, I'd start out making 6-8...  One will be too heavy/light, one will be damaged when 'the tools' do something wrong  , etc.
G-

[TomW]

 One will be too heavy/light, one will be damaged when 'the tools' do something wrong  , etc.
G-

Tools only do what the "tool" running them make them do.

Credit where credit is due is my motto.

BTW, Glen, into 11 days of abuse testing your IGBT driver / controller and still cooking (literally) with no issues.

Tom

[madlabs]

Everybody,

Well, I figgered out a way to cut decent end cuts on the pipe. I only had one factory edge, so I had to do something. I took the rollers from the treadmill, made some brackets for them and screwed them to a piece of plywood about 5" apart. Voila! A handy pipe roller. Then I took my skill saw, attached a couple of hinges to the shoe and Presto! A very snappy large diameter pipe cutter! The pipe was walking as I cut a little, so I took the tread from the treadmill and cut out sections and glued them to the roller. That stopped the walking. One thing I found was that my pipe is far from round. Is this common?

Gurd, pardon me if I'm thick. Well, pardon me BECAUSE I'm thick. Anyway, I could still use some dimensions. Like, how long and wide is the part of the blade that has the bolts? What size bolts are you using? Gimme any detail, I'll work it out in the end but I'd rather not cut a lot of blades.

Thanks for your time everybody!

jonathan

[ghurd]

how long and wide is the part of the blade that has the bolts? What size bolts are you using? Gimme any detail, I'll work it out in the end but I'd rather not cut a lot of blades.

Uhh... you mean the area where the bolts go into?
It doesn't matter as long as it is 'big enough, then twice as big as that'.  The hub is keeping any wind from using that part for power generation anyway.
That area just needs to be "not small" because it will have a lot of torque from the wind.

Do NOT make the bolt hole area like a dinky tab that sticks out from the rest of the blade, or it will break.
I am sure you found the website by the desert astronomer who's black treadmill blades bolt holes were on a section of black pipe about as big as a 5 year olds pinky finger...  Don't do it that way.

"What size bolts are You using?"
Me? My stuff is usually VERY small, and #10 machine or drywall screws is what I would say usually.

I don't have a place at home to fly anything over about 3' dia.
Anything past that is just a couple hour supervised temporary test flight held together with spit, hot glue, more hot glue, luck, and duct tape.
Something with 4' dia, I'd probably use Three 1/4" fine-thread bolts per blade?  But whatever it was, I would use a lock washer and a jamb nut, and the jamb nut would be the locking type type with the nylon insert built in, and I would stake the threads.
1/4" because that's handy, the rest because better safe than sorry.
Some people say its not worth the effort or cost.  The extra effort is 3 minutes.  Extra cost is about $2. 
Feeling like it won't explode at 2AM while you lie in bed listening to the wind howl, Priceless.

Staring at the ceiling at like 2AM, I listened to a $20 32" testbed crash.  Broke my heart.
G-

[ghurd]

Oh,
The pipe is never round.
And it doesn't have the same thickness all the way around, hence the combined issues with blade weights.  It can be a pretty dramatic difference.

I am still standing by the TOOLS messed the bad blades up.
No way I'd drill a 1/4" hole with a 3/8" bit.