PVC tryouts

[nanotech]

One thing learned today :




DO NOT try and hand test a 48" 4 bladed genny in a 35+mph wind!!


I walked out to the end of my driveway, the blades started spinning like an F-14's jet engine, my hand started to get pushed aside and I'm watching these 4 ft blades coming REAL close to my noggin!!  Tried to grab it to furl it, a gust tried to knock it permenantly into my head, I just ducked and threw!!  Busted a freshly cut PVC blade right at the root


Oh, well.  Got plenty more pipe to build more out of!!




I'm not sure what wattage I was getting out of it, but my little drill motor genny was still pumping juice into my little battery pack while lighting a 55W car headlamp.  So I'm guessing it's in excess of 60W.









Just gotta love that brute-force stand, huh??  









And how do you like my Minnesota mounting job??    And yes, the pivot bearing is an idler pulley from a riding lawnmower!!




All was going good until the winds started gusting up around 50mph, and with no furling mechanism at all (other than me grabbing the tail and physically moving it aside, and after my earlier experience that wasn't too appealing an idea!!), I figured it was time to shut it down.

[nanotech]

Oh, and I think I've found a relatively inexpensive source for low wattage bridge rectifiers!!

I had an old computer power supply sitting in my garage, looked on the circuit board, and lo and behold, there's a 4-legged one sitting right there!!  Desoldered it from the board and put crimp connectors on each of the legs....

Now, I don't imagine these will withstand TOO much punishment, but they DO handle 500W+ at 120VAC, so I'm guessing they're good for at least 4A.  Not a lick of heat buildup with all my testing today, and I was pushing (I guess) 5A through it.....

[Bryan1]

Hiya Nano,

          Eh mate by the chepest way to make a bridge rectifier is just use a few 35 amp bridge rectifiers. Over here in Oz Altronics have a special on them $30 for a pack of 10. If you go to altronics.com.au and search for product Z0091 thats the web link to them. The beauty of them is there in a metal package so it's dead easy to mount them on a heatsink. Also there's plenty of info on the net on hooking them up.

Hope this helps

Cheers Bryan

[RP]

Nanotech,

Bear in mind that 500W / 120Vac = 4.16A.  Not a great rating.  Now, to be fair, that bridge might've been on a lower voltage circuit so it may have been handling a lot more as designed.

[gizmo]

There is no way on this earth I would attempt to hand test a windmill in strong winds, its just asking for trouble. The gyro forces on a quickly spinning propeller will mean if you try to turn it out of the wind it will want to tip either up or down, taking out your head or knee's in the process. While you may be able to hold the hub level as you turn, the PVC blades will still flex back and do some serious ( see "fatal" ) damage to you body bits.

If I ever test a windmill at ground height, I use a short 5 foor tower I have cemented in, tie up the dog and stand well back behind the tail so I can turn it out of the wind. Seen too many industrial accident training videos to know how easily something can go wrong.

[ghurd]

An unloaded 28" in 10mph wind is too fast for me to like holding!

Is that 3" or 4" PVC?

How much wind does it need to start that gear box turning?

G-

[nwcpro]

Nanotech,

   Is there anyway you could give some details of that drill motor conversion?  I have several old drills around and have been trying to find some way of using them.

Thanks!

[Texas Al]

Hey, great job. Any chance we can get you to post a picture of the blades when they're still? I looked through your old posts, but couldn't quite make out how you joined the blades to the rotor.

I'm assuming you cut the pipes in half and then bolted them together at some kind of biased angle so that they're oblique to the wind direction?

[joelhacker]

Most PC power supplies now-a-ways are the switching

type and the bridge probably ran to convert a

high-frequency signal into a stable output of ~12 volts.

Most likely, the bridge rectifier was not used for

rectification of the household current (120), but

was for something closer to the output side.

[joelhacker]

Nanotech,

If I remember right, you were using a KMart 18 volt

drill with its gearbox...

I am worried for you about the MTBF of the bearings

in the drill motor's gearbox...is there any idea of

how those little bearings are doing...I don't know

if the drill (or even the brushes on the dc motor)

were designed for that type of 24/7 use???

[nanotech]

It's 3 inch PVC.  With the drill motor attached no-load, it takes almost 20mph for it to start spinning.  

Mind you, my blades are pretty wimpy when it comes to surface area....  

[nanotech]

The actual drill head that I'm using as a generator is from a "Benchtop Pro" 18V cordless rechargeable drill from K-Mart.

As you can see from the second pic, all I did was use some industrial strength zip ties to mount it to that 2X6.

[nanotech]

Actually, I just cut each set to the "Zubwoofer" standards, notched the first set at the root so the second set kinda sits into the notch.  I drilled a 3/8 inch hole through the center of both sets, put a 3/8 inch bolt through the hole from the front and a nut on the back, then stuck the remaining bolt into the chuck on the drill and tightened it down!!  

As Porky Pig would say, "That's it, folks!!"  

[nanotech]

I'm actually only using this for experimental purposes, only running it for a few minutes at a time.

With the blades as unbalanced as they are, my zip-tie mounting system won't hold up much longer than that!!  LOL

I think the longest I left it running was an hour to see what it would do as far as charging the battery pack.  When I heard the sudden increase in rotor speed without an increase in wind speed, I figured the battery pack was charged, so I went and furled it by grabbing the tail and shut it all down.

I'm going to be doing a MUCH better job with the next setup I do, going with 6 inch PVC, and making a PMG generator head with real bearings and mounting system.  This little one I was playing with was more a toy than anything else....  

It was just the fact of all that 35+ MPH wind going by and my mind thinking "What a total waste of electricity!!"  LOL  Every time the wind blows now, I'm always trying to calculate how many watts is blowing by, not how fast it's blowing!!  

[Peppyy]

I know how you feel.

 Watts/Hour = $ in pocket after Electric Bill.

Cost to capture Watts blowing by.... Priceless!

I think you will find that there is a point where the ZubWoofers will only run so fast. I think in your location I would definatly use a furling system also though.

Congrats on your experiment.