Build Your Own Homemade Wind Generator

Marshall Price built his own homemade wind generator, the article includes using wind energy to create free electricity, recharging batteries, and the investment cost to build the wind generator.
By the MOTHER EARTH NEWS Editors
July/August 1986
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Marshall Price's ability to find treasures in trash culminated in the construction of this 2-kilowatt wind-powered generator. His $300 investment has reduced his electric bill to about $20 a month.
PHOTO: MOTHER EARTH NEWS STAFF


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Reprinted from MOTHER EARTH NEWS NO. 84.  

Marshall Price's "Basement-Built" homemade wind generator. A low-investment windplant that's a backyard tinkerer's dream. 

Build Your Own Homemade Wind Generator

"Dunkirk Man Builds Windmill at Modest Investment; Cuts His Utility Bill." That headline, followed by a short article, ran in the August 1, 1978, edition of western New York's Dunkirk-Fredonia Evening Observer. Hardly earth-shattering news, but it did stick in the memory of MOTHER EARTH NEWS editors . . . one of whom paid a visit to Mr. Price at his home on the shores of Lake Erie.

And what our staffer saw there was yet another example of commonsense appropriate technology: Mr. Price, a typewriter repairman by trade and a part-time machinist and welder, had pieced together—for about $300—a wind-driven electrical generator . . . one that has supplied much of his home's electrical needs since Mother's Day of 1976!

Make Do, and Make It Work

Marshall's story really began after the Price family built their lakeside residence nearly 18 years ago. The constant breeze blowing off the water served as an ever-present reminder that free energy was going begging . . . but it wasn't until Mr. Price started collecting information on wind machines, and ran across "a little red book on homemade energy" (THE MOTHER EARTH NEWS Handbook of Homemade Power), that he finally found the answer to the problem that had been keeping him from building his own plant: the need for information concerning the design and fabrication of the all-important wooden blades. Once he'd uncovered that technique, the rest, for the most part, was a matter of locating junkyard parts and fitting them together so they'd be compatible with one another and with the nature of the lakeside breezes to create his low-cost homemade wind generator.

"One thing about the wind here," he told us, "it's darned unpredictable. It can be blowing nicely at a steady 18 miles per hour, and then all of a sudden it whips up to 30 knots without so much as a how do you do. On top of that, it changes direction just as erratically . . . and that can play the devil with your equipment. A 12 foot rotor spinning at 200 RPM or so has tremendous inertia, and doesn't take easily to being reoriented."

It was critical, then, that Marshall Price plan for these contingencies before beginning the construction of his plant. He first scrounged a Delco ambulance alternator that was capable of delivering 147 amps at about 15 volts . . . which figures out to be over 2,000 watts in a very strong breeze. After reconditioning this component, the do-it-yourselfer started working on a governor system that'd allow his three 6 foot blades to feather—that is, pivot on their mounts—when wind speeds got dangerously high. (When feathered, the blades are less effective as airfoils, and thus keep the rotor's RPM within safe limits.)

The hub-mounted control setup Price came up with is similar to the type Marcellus Jacobs used on his well-known wind machines. "I'd read stories about Jacobs, and I wanted to know how his governor worked. I finally located a copy of a drawing from an old service manual, studied it, and then built my own version. It acts on centrifugal force and uses lead weights, linkages, and springs to control the blades' pitch. I knew I wanted a top speed of about 230 RPM on the power shaft, so I just used the trial-and-error method to set up the governor correctly. During the winter I made a little testing stand in the basement and mounted the hub on it . . . then I drove the unit with a belt connected to my walking tractor's engine, took RPM readings off the hub using a tachometer, and experimented with the governor until I got it right. I've been using it ever since, and, by gosh, it works!"

Of course, if it's to generate usable electricity, the alternator must spin a good deal faster than 230 RPM, so Marshall set about making a gearbox that would step up the generator's speed considerably. To accomplish this, he just welded a housing out of 1/4 inch plate and mounted two salvaged Chevrolet gearsets inside. The 8.2-to-1 ratio thus created means that for every one turn the power shaft on the hub makes, the alternator shaft spins 8.2 times . . . or about 1,800 RPM in near-gale (36 mph) winds.

The power shaft itself was recycled from an old Datsun. "I bought the whole car for $10, then sold the body to a junkyard for $15. That left me with the entire drivetrain and a profit of $5.00. I stripped out the swing arms from the independent rear suspension, used one for the windplant-bearings and all—and kept the other as a spare."

Having taken care of governing the high-speed performance of his generator, Mr. Price had to consider control at low RPM, as well. He used a centrifugally activated microswitch-snitched from an electric typewriter—to energize the alternator's field windings when the shaft speed reached approximately 750 RPM. Translated into wind velocity, that means that the generator doesn't start charging until the breezes reach 7 or 8 mph. Below that speed, the alternator is ineffective anyway, so there's little use in allowing battery power to drain into the field circuit at such times.

Finally, to protect his equipment from the inevitable heavy blows that occur periodically, Marshall hinged and "loaded" the windplant's tail frame so it could be folded parallel to the plane of the blades when necessary. A small cable winch mounted at the base of the tower keeps the tail perpendicular to the rotor path under normal conditions, making maximum use of the wind . . . but when that cable is released, the vane swings to one side, presenting the tips, rather than the faces, of the blades to the breeze so the rotor can't overspin.

This method of restraint is commonly used in upwind machines, but in this case, Mr. Price again took a tip from the Jacobs design and set the tail springs so they'd shut down the windplant if the cable broke, rather than open it to the full force of a storm. Marshall points out that he can take advantage of his machine even in strong winds, simply by unwinding the winch partially and allowing his blades to face the breeze at an angle, so they'll spill off a good deal of wind and yet continue to turn rapidly enough to generate power.

Handmade Redwood Blades

A knack for scrounging, coupled with the ability to understand the potential of each junk component, aided Price immeasurably in bringing his project to completion. But he knew from the start that he'd have to fashion the wooden blades from scratch.

"I went and handpicked three straight-grain redwood 2 by 8s from the lumberyard, then cut and shaped them according to the specifications in the homemade power book. Because windplant blades are driven by the wind—they don't drive into it themselves as an aircraft propeller does—their contour must differ from that of a standard propeller to work correctly. After I'd formed and sanded the wood, I protected it with fiberglass resin and matting—coating it evenly to maintain proper balance at speed—then roughed up the glass lightly and gave each blade another coat.

"Now those redwood airfoils aren't just bolted to the hub . . . each spar coming off the governor pinions is 7/8 inch-diameter cold-rolled steel, and extends a full 20 inches into a socket that's been bored into the blade. Furthermore, these internal spines are pinned through the wooden shoulders, and I've also got them sandwiched on the outside with 6 inch by 6 inch metal plates. This way, I can have my feathering feature as a governor, and still feel comfortable about the integrity of those redwood blades at higher wind speeds."

The Chain's Weak Link

After fabricating the blades and working out the best method of mounting them, Marshall had only to erect a tower and place the plant atop it. Since the source of wind is generally from the lakeside quadrants and doesn't suffer interference from trees or hills, it wasn't necessary for Mr. Price to build a fancy lolly pivot or to rely upon altitude to catch the best breezes. He simply sank a length of well casing into a concrete footer, leaving about 18 feet of the casing exposed. Then he mounted the generator and gearbox on a frame and set that into the tower so it would pivot on a vertical axis. Double-aught copper cables (purchased at scrap prices from the local power company), given plenty of slack to allow for yaw, carry generated current to the battery bank.

Energy storage is, according to Price, the weak link in his system. "There's absolutely no problem at all in making the power . . . that's the easy part. But decent storage-something that's affordable and can still take the abuse of constant charge and discharge—is darned hard to come by."

Marshall wanted [1] a system that would allow him to be somewhat independent of the power companies, and [2] one that would be working even when the wind wasn't. As his setup stands now, the outsized alternator generates alternating current, which is rectified to direct current through diodes, then stored in a mixed grill of batteries composed of 2- and 6-volt cell blocks. That bank is wired in a series-parallel circuit to achieve 12 volts total, and that power is fed through a stand-alone inverter that converts the storable DC back into AC, for use throughout most of the house.

Mr. Price doesn't use a voltage regulator on his system, because the batteries—when they're depleted—require a good three days of steady wind to even approach the overcharging point. In fact, he simply uses his appliances as indicators of his storage bank's state of charge: "I can tell by the way the lights bum. If they're too bright, I know I'm getting more than 13 volts instead of my usual 12.5, so I have to shut down the plant. On the other hand, if the batteries are low, the picture on my color TV gets distorted-in the upper right-hand corner, and that tells me it's time to crank the tail out straight again. A few years back, we had a nine-day spell without any appreciable breeze, and the cells were able to handle that, so I'm not too worried about my storage capacity."

Of course, batteries do lose their effectiveness. But Price stresses the importance of maintaining a cost-effective approach to these essential pieces of equipment. He cites as an example an offer that was made to him some time ago: "A fellow had three huge Pullman car batteries that he wanted $3,700 for. Now if I'd invested that amount of money at 10% interest, it would have paid my power bill for quite a few years to come, so those Pullman units weren't a good buy. It's better to get a number of smaller batteries, pay maybe $25 apiece for them, and use them to the bitter end. They might not last as long, but at that price I could afford to replace them."

A Sound Investment

Has Marshall Price's investment—of both dollars and time—been reasonably rewarded? Interestingly enough, he admits that, at first, his main objective was simply to have one wind-powered light source over his reading chair. Then, as he made improvements in his plant and added more lights, he boosted his storage capacity as well. Eventually, seeing that the generator easily kept abreast of his power usage, he installed the inverter and then tied other appliances into the line. Today, everything in his household is powered by the wind, save for the dishwasher, the washing machine, and the refrigerator . . . and the cost of operating (and enjoying) those induction-motor-equipped conveniences usually doesn't exceed $20 per month.

In summary, Marshall Price is an example of someone who—with the help of his welding and metal-shop skills—turned several hundred dollars' worth of scrapyard parts into the equivalent of a several-thousand-dollar investment . . . one that demands little more than an annual checkup and a battery recruiting effort every so many years. It doesn't take a very sharp pencil to make sense of economics like that . . . because this Price is right! 


One Step at a Time

It's not difficult to imagine that many stand in awe of Marshall Price for taking on such a formidable project and seeing it through to completion. But even Mr. Price, as a veteran tinkerer, approached his goal systematically, using the most basic means at his disposal. If Marshall's success story has you itching to try your hand at a wind energy project of your own—but you don't know where to begin—here are three approaches. The one you choose will depend upon how comfortable you are with your shop skills.

The simplest' and least expensive project is the MOTHER EARTH NEWS Red Baron trainer—a 70-watt wind machine which our staffers developed as an entry-level undertaking that would cost less than $100 to build. It'll provide its builder with some valuable experience and usable electric energy, and can also serve as a monitor for a proposed wind site. Six pages of detailed, step-by-step plans and photos are published in the article beginning on page 96 of MOTHER EARTH NEWS N0. 92.

A more sophisticated windplant (but one that's not much more difficult to build) was featured in issue MOTHER EARTH NEWS NO. 93. Dubbed the Blue Max, the 350-watt wind generator is a reliable power producer that can be built for as little as $200. It, like the trainer model, uses off-the-shelf plumbing fittings as frame components, so assembly is almost a cut-and-paste operation. Because there's more detail work involved with this machine, we put together a set of construction plans (in addition to providing information in the five-page published article). They're available at a cost of $10.00, plus $1.50 shipping and handling, by writing to Blue Max, THE MOTHER EARTH NEWS PLANS, Hendersonville, NC.

Finally, if you feel confident about tackling an advanced workshop project, Marshall Price has cooperated with MOTHER's staffers in producing a plans package that details his 2,000-watt wind machine. The package costs $15.00, plus $1.50 to cover shipping and handling, and is available from the address above; please specify Price windplant when you order.


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Post a comment below.

 

DM Hebert
6/29/2008 12:22:56 PM
I am not new to the expert, easy to understand information of the Mother Earth News. Even though this article is more than two decades old, I knew that this article could help me with a home generator. I also knew that the information would be relatively timeless. I have taken the information I needed, using the proper reference source tags. Thank you for another successful project, Mother Earth News. DMH








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