Portable 12 Volt 17 Watt Wind Generator with Automatic Furling

Step 4 Mast and Rigging for the Portable Wind Generator:

Designed to fully take advantage of gusting wind conditions, the wind generator has an unusually large tail fin, as well as a ball bearing fitting on top of the mast. This enables the unorthodox device to quickly seek out and turn into the next wind gust, with the flywheeling blades always ready to harvest the often erratic and meager winds. The large tail fin also stabilizes the device during furling, holding the wooden body straight-and-true, into the wind.

A lightweight, but strong, 24" long stainless steel mast-pivot tube was cannibalized from an extendable shower curtin rod, from a local hardware store. The tube is a sturdy thin-wall construction, internally butted with plastic sleeves on the ends, providing a low-friction pivot that slips perfectly over the 1" diameter fiberglass mast.

The generator, Aix-X blades, wooden mount, tail fin, stainless steel mast-pivot tube, and power cord all weigh in at 9-1/2 pounds, total, and mounts lightly on top of an extendable 10 foot tall fiberglass mast pole (actually a modified tree pruning pole), in perfect balance. 4 guy-lines and hardware mount complete the rig.

I have recently replaced the original 10 foot tall mast, with a 15 foot tall extendable fiberglass mast (also a tree pruning pole), providing much better wind exposure, but the rigging needed to be refined to handle the increased stresses on the mast:

- Four additional guy lines were attached to the mid-section of the mast and tied to the four original ground stakes.

- A ball&socket plastic water shut-off valve was modified into an articulated ball&socket base for the mast.

The setup of the portable generator and mast is now greatly simplified by the ball&socket base:

- A plastic stake is fully driven into the ground, for the mast.  The stake is then carefully pulled out and the special, custom made ball-topped mast stake is pressed in its place.

- The looped end of a white nylon rope, with a red mark @ 13 feet, is slipped around the round shaft of the ball-topped mast stake, and the four anchor stakes are driven in, exactly 13 feet from the ball-topped mast stake.

- The non-looped end of the 13 foot white nylon rope is drawn taught and tied  to the ground stake that is downwind (leeward) of the mast.  This holds the ball-topped mast stake firmly in place for the set-up and take-down side stresses that will follow.

- The 15 foot mast is fully extended, with its internal wire connected to the wiring of the wind generator.  The wind generator is then slipped onto the top of the mast.

- The socket base of the mast is snugged onto the ball of the ball-topped mast stake.

- The upper rigging (4 guy lines) is attached to the mast, and 3 of the guy lines are attached to the ground stakes EXCEPT the 4th guy line that is upwind (windward) is NOT attached to its ground stake.

- Firmly grasping the 4th guy line, standing above the upper mast anchor, gracefully pull up the wind generator and mast, while walking back into the wind, and attach the 4th guy line to its ground stake.

- The entire rig will now be in its vertical, perpendicular, position and requiring only minor adjustments.

- Attach the lower 4 guy lines to both the lower mast fixture and ground stakes.  Carefully tension all 8 guy lines until the slender, flexible mast is straight and true.

- Take-down of the wind generator / mast is simply the reverse of the above.

The generator, from shaft arbor tip to tail, measures 45 inches. The power cord is routed through the ring-shaped ball bearing fitting, and inside the hollow, fiberglass mast. A standard RCA audio jack, used as an electrical connector, slips easily through the 5/8" diameter hole in the ball bearing fitting of the mast and down through the hollow mast. A slip ring (rotating electrical connection) is not needed, as a portable wind generator only pans a total of about 270 degrees, on a typical day.

The rigging attaches to a square piece 5" x 5" plywood, 11/16" thick, and glue mounted (PVC glue bonds well on both surfaces) to a PVC pipe which slips over the 1" diameter fiberglass mast. A thumbscrew tightened ring was fitted over the radial-cut end. 4 angled, thin plywood braces will later be added to the underside of the 5" x 5" plywood, for reinforcement.

The 4 guy-lines are firmly anchored into the ground with 17" long, heavy, steel "cork-screw" stakes.

The entire rig is easily set up and taken down by one person.

A side note:

I was recently invited by a local ham radio club to set up my portable wind generator, for their international ham radio day.  I was quite impressed with their portable 24 foot antenna masts, made from interlocking U.S. military surplus antenna mast poles.  These sturdy (2 lbs each), inexpensive, 4 foot long composite (resin impregnated glass fiber) mast sections can be purchased on ebay.  The mast sections have an outside diameter of  1-13/16", an 1/8" (.125") wall thickness, with a 3.5" long male/female coupling end.

Also, standard military surplus composite 4-point guy line attachment rings can be purchased, which slip on easily between any of the 4 foot section joints.  The guy ring is 5-11/16" diameter, drilled with four 3/8" guy line holes, with a 1.531" diameter center hole.

These pole sections not only allow for taller and stronger portable wind generator masts, it also makes the reality of truly portable 500 watt (500 watts rated = 75 watts typical) wind generators not only possible, but much simpler and affordable.       

Comments

[jetboy]

where did you purchase the motor at

[Harry3Lime]

How far from the pole are the anchors placed?

At what heights are the guy wires attached?

[shastalore]

The distance is already stated the instructable, but is always dependent on the height of the mast, so I'd rather not state an exact number here.

But a good rule of thumb is to place the upper guy wire hook-up as high on the mast as possible.

And for the distance for each of the four anchor stakes from the base of the mast, the guy ropes should be at a 45 degree angle, both from the ground, and the upper guy wire hookup.

But if you're setting up on sand -or on solid ground but with high winds, then 30 degree / 60 degree angles will provide better stability for your rig (30 degree angle from the ground / 60 degree from the upper guy rope hookup).

And for a mast taller than 10 feet, especially a slender, flexible mast, you will need to add a lower guy wire hookup, about one-third to halfway down the mast, and anchor those lower ropes to the same four anchor stakes. The exact positioning of the lower guy wire hookup is best fine-tuned during high winds, carefully observing what position provides the best bracing and rigidity of the mast.

And don't hesitate to add yet a third guy wire hookup, if you're really ambitious and building yet a taller mast than my 15 foot version.

[der_fisherman]

I cannot see any prevention of the axial loads damaging (eventually) the motor bearings. Please be aware that most electric motors are NOT designed for such loads....in the long term at least. Especially if not ball bearing in the first place..... It could be possible to change one or both of the ball bearings for a bearing that is good for both axial and radial loads. though actually one is enough usually.... Or one could add an external axial bearing at the end where the prop is mounted (assuming a windmill design where the prop faces into wind). I use a similar arrangement on my homebuilt CNC bearings, at each end is a single (normal) radial bearing and at one end 2 axial bearings either side of the radial bearing, but putting the load on the frame.... as that is cheaper than a single ball bearing for both load types..... If you happen to find/use a DC motor that has a brush system that can be adjusted/moved radially, you will find that the best position for the brushes as a generator is quite different to that needed by a motor, maybe as much as 30° different (if I remember correctly), so by such an adjustment (if possible) you can seriously "up the output" quite dramatically for the same revs....though most motors do not allow such playing around.....the brushes are fixed in position.... I have read that stepper motors can make useful generators, but have not tried it personally you understand.....but as they have no brushes, a point of serious long term wearing is reduced, as is the need to find the optimum position for the brushes! So higher output will be easier to achieve..... But do remember that the output is multiphase AC, so a few diodes are also required.....No big deal...... Please do not see my post as critic, its meant into be helpful to both yourself and anyone else planning to do the same or similar......Otherwise I liked your post, easy to build and very useful.(me being a camper for some weeks each year....!) Regards and thanks for your trouble and ideas.

[shastalore]

You're right, there are axial load stresses on the generator shaft. But with the well-designed and efficient Air-X blades, my main concern was the centrifugal forces of the fast-spinning blades, on the ABS hub. But the axial load is moderate, and will never exceed 2 pounds anyway. But only time will tell. The generator is quite small, for the size of the blades, and stresses, both axial and radial, are present. But the motor was designed for use with a belt and pulley, so it can be expected to handle the radial forces in stride. The small, sealed ball bearings are replaceable ($ 8.00 each), but periodic rotation of the outside of the bearings, should give a lifetime of service, since the generator is for portable, intermittent use. The only bearing that would be subjected to the axial stresses would be the one in the tail-end of the generator. And that's assuming the it was not designed to handle axial stresses, and something that might have to be dealt with later. In this motor, the flat end of the tail-end shaft is inside the housing, so it could be drilled out and some sort of axial ball bearing could be retro-fitted, in addition to the existing radial sealed ball bearings. As for the timing of the generator, one could certainly file off the die-cast timing notches on the casing of the tail-end of the generator, and, in a 600rpm bench test, rotate that end, back-and-forth, until the optimum current is produced, then drill out new holes, for the full-length housing bolts, on the generator housing. I also understand that this can be done in a static test, by measuring resistance only, while simply advancing/retarding the brushes, but I have been unable to duplicate this. Maybe someone here can provide more definitive information as to how to do it. I advocate DC, carbon brushed, permanent magnet motors, for simplicity. This particular motor has carbon brushes mounted on external holders, making them quick and easy to replace. Diodes, etc., tend to overwhelm the novice experimenter. Although, if someone manufactures these wind generators for the mass market, I wouldn't be surprised at all if if they are produced with brushless motors.

[JoeCools]

Speaking of Boy Scouts, I have 1 still in Scouts and the other is an Eagle Scout, when ever we set up any kind of lines, we use highly visible fluorescent ribbons 3 to each guide rope so the young ens can see that a rope is there and not to trip over it. Great Instructable! Thanks /Joe

[shastalore]

thank you

[kerns]

Great explanatory photo showing your 'warning' guylines. I might suggest adding "crossbar lines" for added safety. Place loop knots on each existing line at knee height; create 4 additional orange lines with a carabiner or similar wind-proof clip at each end, and clip on those lines to create a knee-high visual barrier to "box in" the danger zone near the possible zone of blade passage. Maybe tie mylar strings to those crossbar lines for added visual presence - could also be great places to hang informational signs if the generator is being used as a learning piece. Great work, fantastic Instructable - thanks! -Kern

[shastalore]

For an EarthDay exhibit in the park, your suggestion would work quite well, as some parents might try, to hold their little children up, to playfully paw... at those sharp, hideous spinning blades. And I would definitely put my old Boy Scout knots back into use to prevent that. Your detailed description serves well for this. But for a high-mountain camp, say, in Tibet, my basic rigging should do just fine, as a fully grown adult would have to leap in the air and take a good swipe at the blades to get injured.