Use Existing Windmill to generate power.

[kramerica]

Any information on taking the pushrod from an existing windmill and using it's 7 inch throw to generate power?  

[Nando]

Can you explain in detail what is what you mean by a push rod in a wind mill?

Is this wind mill a water pumper ?.

Nando

[Nando]

Heck I did not read the heading.

The rod movement is too slow for power generation.

Nando

[K3CZ]

In general, water pumping windmills have many blades of steep pitch, because they are designed to produce high torque at low speeds (0.5 rps, typical top speed). Therefore, a crank and lift rod are linked directly to the prop shaft and to the piston pump below. To gear this up to the 120 rpm necessary for even the most efficient alternator is not very practical nor efficient. Some work has been done with a rim belt on the blade structure driving a small higher speed generator/alternator, but the mechanical complexity and the number of things that can go wrong are quite intimidating.

You would be better off utilizing the tower with a new axial flux direct drive machine per the Dans'.  After all, an erect sturdy climbable tower is more than halfway to a final operating machine!  

                                Good luck!       VAN    K3CZ

[Warrior]

I agree with the other members. While you would probably be able to get some power through gearing, it's much easier and reliably to build one of Hughs or Dans axial flux machine.

I have built a chain driven 2 mt turbine, geared at 3:1. It didn't seem to have problems starting up and drove my generator with ease, but it was noisy, complex and heavy, just for a 300 watt machine.

Plus you already have the tower, the most important part of the wind system. A good Towers may cost more than the the generator, and you already have the advantage of being able to climb safley for maintenance or testing.

You can alway build a new, more powerfull genny, but a freestanding tower such as yours is not something easy to build or buy.

Good Luck

Warrior

[kramerica]

Yes this windmill is designed for pumping water.

[jimjjnn]

Some people are lucky in as much as having a tower ready for a garbogen, DanB special  or Piggott mill.

If that were my tower, I'd have a genny with good set of blades and furling system on it very fast.

[Chagrin]

Pushing a magnet through a wire-wrapped tube will generate electricity. How efficient that is is a good question, but it'd be worth exploring considering the simplicity in adapting it to your existing windmill.

Multiple magnets and coils (each seperated 7" apart along the push rod) would probably give a more convential axial-flux machine a good run for its money. Certainly a lot easier to construct!

[Norm]

  Just pump water onto an overshot waterwheel

hooked up to a generator....

                 ( :>) Norm

[terry5732]

At 150 pounds I was easily lifted off the ground by one of these and think they would drive a gearbox nicely.

I still don't see two or three thin blades outdoing these. Two blades can obviously turn faster, but there is no way they grab as much wind.

[Ungrounded Lightning Rod]

The blades affect the air in front of and behind them.  The air doesn't have to touch the blades - all that has to happen is that the blades slow a slug of air and then get out of the way and let it leave and another not-yet-slowed slug come in before the next blade comes by.

Those thin blades, with airfoil shapes to get lift from the passing airstream and use it to pull them along, spinning rapidly, are extremely efficient.  They can get within a couple percent of all the power you CAN get out of a given cross-section of air with a windmill.

Meanwhile the fat, curved-sheet-metal blades of the slower-spinning "patent" windmill designs have negligible lift and are thus quite inefficient (despite appearing opaque).  For pumping water in a field that's fine - you don't need efficiency.  Sheet metal is cheap and you can just make your blades bigger to compensate.  You don't need speed either - what you need is a lot of force, to insure starting in low winds and to lift the water.

For generation you want speed - because the faster your genny turns the more power you make for a given amount of expensive wire and magnets.  In addition to being efficient, those thin airfoil blades also move with a tip speed several times the wind speed, making them fast.  Very good.

(There's a graph circulating that gives the efficiency of several different types of rotors.  You'll see that the horizontal-axis airfoil blades are very high, and the patent windmill is far down.  But it's worse than that:  Most of the copies circulating have the labels swapped between the patent windmill and the savonius rotor, making the patent windmill look significantly more efficient than it actually is.)

Imagine it as a glider wing moving in a straight line rather than a circle.  Efficiency translates to glide ratio.  Do you think your glider will go farther for a given altitude loss with a variable-thickness airplane wing or a simple curved sheet of metal?  (Hint:  It's harder to make the airfoil.  So if a curved sheet of metal worked even nearly as well that's what airplanes would be using.)

[oztules]

I agree with your general thrust that the 3 blade hawt is more efficient than the pumper style, but I think you are overstating the difference in efficiencies and useability of the older slower style.

This company :    http://www.turbex.co.za/WindGenerator.html  has a very tidy unit, 18' 5kw@ 25-26 mph. not too shabby.

 There are advantages with the pumper style unit. It is very slow revving (48rpm this one) and so maintenance will be very minimul, it is tried and true, and is very unlikely to cause any problems with noise and asthetics...plenty of this type around, and loved by one and all....maybe nostalgic, who knows. I like them too.

One other advantage with this style is the low wind performance 1/4 kw at 10 mph.

Looking around the net, it seems that you correctly put the efficiency higher for the 3 blades (well designed airfoils around 42%) as compared to the multiblade pumper (around 30%)

The difference is not so great when you take into account that most blade sets made here are not premium designs, but are rather compromise designs between the ability and ease on the one hand and top performance on the other. We are probably in the 35% and less range.

The pumper type is easy to fabricate, and will not vary too considerably from the 30% for best design.

Taking these factors into account, the real difference is probably in the gearbox/no gearbox part of the equation, not so much in the efficiency of the airfoils, which in most cases will not be that great.

If I were to be buying one, I think I would go for the slower Turbex design. I know it will outlast a higher speed design. Old mills on properties near here are still going strong 50 years on. They still squeak as they rotate on their hardwood bearings, but they still work as well as the day they were built.

The pumper gearboxes are near perfect when you open them up out of curiosity (I have two). In our country we have gearboxes, in USA I see they refer to cranks driven directly off the main shaft. I don't know their longevity.

All in all, the pumpers are not out of their league at all, and I feel they offer some distinct advantages ie. long life, low noise, good slow wind harvest and looks (not the least important).

...............oztules

[nanotech]

I'm trying my hardest to get a few of my nearby neighbors to surrender thier old (inoperative) pumper mills to me.  I somewhat agree with oztules here that yes, efficiency is important, but only to a certain point and then it gets into the "anal retentive" area.

Yes, they may be slow turning, they may not be as efficient as a Hugh Piggot style mill.  But as oztules has stated, darnit they've been spinning for 50 plus years and the only reason they are no longer used is because of electric well pumps (like I have).  I wouldn't actually mind having one setup as an actual water pumper for when the power goes out around here and we can no longer flush the toilet because the electric well pump is down.

But for the most part I want them for thier towers.  If those towers have withstood everything the local environment has thrown at them, then they are a tried, tested, and true system.  That's what I want.  I don't want one of my "redneck" towers falling on the house because I tried to make my own.  I want to go with something I "KNOW" is going to work (unlike my redneck woodburning stove)!!

[redeyecow]

   I built a chain drive adapter on the brake hub of my 8'water pumper a few year's back. Using a regular GM alt. and chain drive jack shaft, it was running about 50 to 1.

  Although it did produce some power in big wind, it was basically impractical most of the time.  I found that the rotor will only get up to about 60 rpm completely unloaded.

   I put it back to it's main purpose, pumping water. I have been thinking of adding a

stub tower to the top of the pump jack with a pma attached and take advantage of the existing tower. Also thought of a platform out to the side of the main rotor with a stub tower on it.

   keith

[RP]

Kramerica...  I remember now, you were the company that was going to transport crude oil in big rubber balls.  As I recall they failed in the intial testing when a prototype ball burst after being pushed out a window of the ball factory.

LOL.  For those that don't know it, this is a refernce to an old episode of Seinfeld.

[anewlinii]

Does anyone have any documented proof as to the difference between the 2 to 3 blade rotor design to the 36+ blade design.  The U.S. Government wont even test the two side by side.  Gee I wonder why with all the big money greasing their palms so they wont even consider anything other than 3 or less blades.  The Department of Energy is just as corrupt as any other U.S. Government Department.  Not that I am bitter or anything.  I will be going with the South African Turbex, just because it will make the U.S. Unions more happy. And they wonder why everyone is buying overseas.