It all started years ago with a broken treadmill
I’d read stories of people who would “harvest” the motors from treadmills and give them another life by building backyard wind turbines. The thought piqued my interest.
When our treadmill broke down we decided that 10 years was a good life, and “donated its parts to science.” I tore the thing apart in a herculean feat of what the neighbors would have described as the mad absurdities of a lunatic. Ultimately I salvaged the DC motor, it’s hub, and mounting bracket and hardware, thoughts of free electricity tantalizing my wildest imaginings.
I cleaned up the shrapnel that our treadmill had become and placed my golden eggs neatly on the work-bench, a project for another day. And there is sat… for years.
I was dabbling with the idea of building a horizontal-axis wind turbine in Darius- or Lenz-fashion, but opted for the more traditional approach of a vertical-axis wind turbine. I found some plans for fabricating my own blades out of 6-inch schedule 40 PVC drain-pipe, printed them out, and there they sat… for years.
Time droned on
I got a new job. I graduated from college. My kids grew old enough to be interested in science and hobbies… and my desire to tilt at windmills was rekindled.
With the donation of a tetherball pole (the kind cemented into an old tire) I finally had a “test tower” and lost my last excuse to put off building my opus. I dug out my plans, acquired some 6-inch PVC pipe from my dad, dug out the old motor and mount, and purchased some hardware to make a pivot and tail.
I carefully measured and cut two blades from the PVC and (with the help of my little brother) tapped eight holes in the hub. Later I mounted the motor to the home-built pivot and attached the tail. I had the makings of a real wind-turbine. I carefully mounted the PVC blades to the hub and raised the hole apparatus ten feet into the air on the tetherball poll. As Murphy’s Law would dictate, we had no wind for days, so there the turbine sat, perched majestically atop its improvised tower, two arms reaching out, aching for the wind to catch them and whirl them around.
Finally, in the middle of the night, that time came
The wind gusted and spun the blades… and because I’d cut them backwards, their spinning unscrewed the hub which fell unceremoniously to the ground. The next morning my 7-year old daughter came running in, “Oh no! Daddy! Daddy! The windmill is broken!” It’s what I was afraid of, and why I only cut two blades: The motor had a clockwise rotation, but the blades I’d cut spun the hub counter-clockwise (or “anti-clockwise” for those of you across the pond). I acquired some new PVC pipe, this time I went for 2.5 feet instead of 2 feet (which I’d used on my initial attempt). The extra foot of “wing surface” I figured would help in my low-wind location). I also cut the blades a little “thicker” which will slow them down in high-winds, but should cut in faster in low-winds.
I mounted the new blades just in time for a whopper of a storm front to blow in. The new blades worked, and worked well, spinning at a horrific speed that I wouldn’t have imagined.
I hooked up my multimeter and measured the voltage: 2.4 VDC. Not what’ I’d hoped for, but at least I knew why the treadmill didn’t work.
I learned some good lessons though:
- furling is important to keep your the thing from becoming a whirling contraption of death (to paraphrase one of the people who’s built his own wind turbine).
- making sure your pivot actually lets your turbine face directly into the wind is important (mine doesn’t turn all that easily)
- don’t try and hook up your multimeter to the wires on the motor while the turbine is spinning. I could have lost an arm.
Beyond the prototype
I decided I needed to get a real mount and a new motor. Off to eBay. As of this writing I’ve got a bid in on an AMETEK 5" 37V Permanent Magnet VDC Motor (which is what a lot of the other guys are using for their turbines). I also bid on (and won) a mount with pivot and tail from alternativeamps (WIND GENERATOR / TURBINE / AMETEK MOUNT WITH VANE (NEW), 2 NYLATRON HIGH IMPACT GREASELESS BEARINGS INSTALLED). It was delivered about a week after ordering (give or take).
When I received it I noted that there were some drips and bare spots in the paint (others had left feedback indicating similar conditions), but overall it was a very nice looking and seems very well constructed.
Also, absent in the packing was any kind of instructions. I was hoping to see some tips, which way is “up” and which side to mount the tail on for furling to work properly (if it even mattered), but there was none.
I submitted positive feedback: “Good product for the price. No instructions were included; spotty paint job.” Almost immediately I got an email response, and no, I’m not making this up:
I read your feed back, if your so stupid that you dont know how to put in 2 or 4 bolts, you really ought not be messing with electricity. for 32 dollars and you had to say something like that, neg or positive, it makes no difference. its your actions by words. youve now been blocked from further purchases. have a nice day.
Really? So I replied:
Wow… I really don’t know what to say.
I left positive feedback because I feel you made a good product for a very good price.
I went further to say that the paint was spotty in a few places (I’ll easily touch that up before I install it); and there were no instructions. I had questions like "does it matter which way is up?" and "does it matter which side the tail goes on?" and "how does furling work?"
This would be simple stuff that I felt would help you improve your product. With your instructions you could have included a list of what else you make and links to "how to make your own wind turbine"… You know, stuff that would make people likely to buy from you again, refer you to their friends, etc.
With the kind of response that you gave me when I blog about your product how can I write anything other than "made a good product but banned me from buying anything else from him when I left positive feedback aimed at improving his product"?
most people will ask for things like that before they leave a feedback, ive been know to give out free products,say hubs and arbors, to make people happy, free shipping, all kinds of free stuff, but not after the remarks. blog all you want, I can do the same have a nice evening. give me the link on the blog and ill help ya
So, at least (with a little elbow grease, some paint, and some trial-and-error) I’ll have a good pivot/mount for my turbine thanks to alternativeamps on eBay. Unfortunately I won’t be able to buy any of his st
ever again (because he “banned” me from buying from him) when I make more turbines, but there are other sellers.
Now I just need to win my auction on the new motor, get a blocking
transistor diode (to prevent the motor from spinning from battery power), install my “tall tower,” acquire a charge controller, and hook the whole thing up to a battery and I’m all set. Obviously I’ll write more when the story continues, but I had to get this much down “on paper” otherwise the resulting post would be far too long…
The rest of the story
As promised, I’m detailing the construction and installation of my Backyard Wind Turbine, here: http://www.joelevi.com/blog/index.php/2008/09/24/backyard-wind-turbine-part-1/