Hi Joseph OLall and Others! My Project Introduction

[Jim Mac]

Hi all, Allow me to introduce myself and what I am working on.. I have been working on a windmill and was lucky enough to meet up with Joe OLall who lives near me. I'm in the Poconos (in PA) and this is my first real build attempt.

Initially, I was going to build my own pivot and do it all custom, but I soon realized my welding skills are not yet adequate for this type of project, so I worked with various companies and made some headway.

This is a picture of the generator (unmodified) with the bearings, tail furling hinge, and ya bearing in place.

http://store.unexplainable.net/stuff/windmill/NewCompletePivotAssy.JPG

This next picture is my sloppy job of rewiring the stator. There are 36 coils, so I grouped them into 6 groups of 6 coils and wired them to create 6 groups of 2 poles. Note: the white bearing case is not part of the finished mill. It was used for hand-spinning testing. The stator connections were coated with hot-glue and several coats of enamel were applied. Looks a little sloppy, but it will do the job.

http://store.unexplainable.net/stuff/windmill/stator.jpg

And the following picture is the blades I will start out with. I have 2 hubs. 1 with a 3 blade setup, and one with a 5 blade setup. I will probably go with the 3, but if I need the 5, I have it.. The blades have like a 60" total span.

http://store.unexplainable.net/stuff/windmill/HyperSpin-5blade.jpg

The hub and shaft are at the welding shop and I am looking into charge controllers..


I still need to construct the tail vane, the mounting gin pole, and acquire the battery bank. The generator should be able to hit over 500 watts in good wind. I will keep you posted on progress:rolleyes:

[Jim Mac]

The F&P Smartdrive turbine is taking shape. I can foresee liftoff:idea: I Attached photos of the progress.

Now I am facing the issues of erecting a tower or pole . With the town ordinances and my property measurements, I am limited to a 35' turbine from ground to blades highest point.

This puts me back in the woods. There is a clearing, but the surrounding trees are taller than 35'. So price is down, but efficiency is also down:( To make matters worse, there is a highway runoff which interferes with guy wire placement. It seems the hardest rule is keeping the turbine far enough from my own house.

It's a shame I can't get it up high, but hopefully I will find a way to launch it. I will post pics again when and if it happens.

[Ralph Day]

Hi Jim
Welcome to the GPT forum. I think I saw your project on the NAWS site?

I like the 3 blade setup. It kinda looks like the macerating blade in the Saniflush toilet I just installed. Birds better watch out!:sick:

Ralph

[Rob Beckers]

Jim, where does the alternator come from? It looks a bit like the DC motors used in washers. Is that what it is? Any specs on power/voltage/rmp?

-RoB-

[Jim Mac]

Jim, where does the alternator come from? It looks a bit like the DC motors used in washers. Is that what it is? Any specs on power/voltage/rmp?

-RoB-

Yep, it's a Fisher and Paykel Smart Drive Washing machine motor. I heard people say they can produce up to 600 Watts as a turbine, so I assume 6-8 Charging Amps is considered good with this motor.

I will know more once I do do some testing. I'll keep you updated.

I am now looking at the 30' 1810 towers offered by American Tower. A company representative told me it should qualify for permits. So I am struggling with the math to prove it.

If the tower has a load capacity of say 75 square feet, am I just comparing this to swept area?

[Rob Beckers]

Hi Jim,

Could you tell a bit more about the washing machine motor; what's involved in the conversion, and how much they go for. If anyone has measured a power and voltage curve I would be interested in that as well.

I'm the wrong type of engineer when it comes to structural engineering. However, the tower analysis that I see being done by engineers uses energy extraction to determine rotor thrust. Basically they assume the rotor is working at Betz limit (so thrust gets overestimated), then add a safety factor to account for wake vortices and such that also eat energy. The equation is as follows:

Thurst [N] = 0.5 * Area * Rho * (Vin^2 - Vout^2) * 1.3

With "Area" is the rotor swept area in [m^2], "Rho" is air density in [kg/m^3] and that is 1.225 at sea level, "Vin" is the wind speed going into the rotor in [m/s], maximum thrust is usually just before furling, for example 14 [m/s], "Vout" is the wind speed coming out of the rotor in [m/s] and it is normally assumed to be 1/3 of "Vin" (essentially the Betz limit). The factor of 1.3 allows for wake vortices induced thrust. This should overestimate thrust somewhat, to be on the safe side.

So, if your rotor is 60" diameter, or 2.54 *10^-2 * 60 = 1.524 [m]

That makes a swept area of 3.142 * 1.524^2 / 4 = 1.824 [m^2]

The thrust would then be 0.5 * 1.824 * 1.225 * (14^2 - 14/3^2) * 1.3 = 253 [Newton],
and that is about 0.225 * 253 = 57 pounds force. Assuming your turbine furls before 14 [m/s] in wind speed.

Now to the tower side of things:

If the manufacturer gives a flat plate surface area, there should also be a maximum wind speed that this is rated for. A usual value is 90 [mph], or 40 [m/s].

Drag for an object is:

Drag [N] = 0.5 * Area * Rho * V^2 * Cd

With "Cd" the drag coefficient, which is 1.28 for a flat plate.
An area of 75 [ft^2] is 6.97 [m^2].

That makes for a drag of 0.5 * 6.97 * 1.225 * 40^2 * 1.28 = 8743 [Newton]

Now, if all that is correct (and I'm not giving any guarantees here! :wacko:), your tower would be massive overkill...

-RoB-

[Jim Mac]

Hi Rob,

I can't tell you the precise details, but this page can. http://thebackshed.com/Windmill/Contents.asp

It seems the Australian Turbine Enthusiasts center their focus on these F&P motors to build low cost sturdy windmills. As I understand, the Oasis US washer and the newer LG machines are now using these smartdrives. Since there is online manuals and support for the F&P conversions, I decided to work with the proven model.

You can find these F&P smartdrive motors in the USA for around $130 for the stator, rotor, and shaft. You will need to get some 25mm bearings and design or find a pivot to fit. Modifying the stator isn't difficult, the magnetic wire is easily accessible so it's a matter of clipping the wires and soldering them in different configurations of your choice.

Thanks for the math above.. I will dig into it.. After speaking to the zoning officer about a removal bond, I am now considering the guyed Gin pole.