As some of you are aware, about six years ago I began a very ambitious scratch built, DIY endeavor to build a VAWT to enable me to go off-grid. That project has been an enormous challenge in many ways but is nearly completed. If there were blades on it today, it would be making power today. The four large blades, each the size of a small airplane wing, sit patiently awaiting my attention at the base of the large machine in my work yard. Most of he work on the blades has been completed but they still need to be skinned.
As we all know, as far as going off-grid goes, you have to have back up systems in place in case your main source of power breaks down or for off-time to perform preventative maintenance, etc. In my case if the big VAWT were to misfire in January here, it would be a long cold winter before it got warm enough outside for me to get to any repairs. It is therefore essential that I have a second wind tuirbine here in operational status as a back-up. The bonus is that although the main reason to build a second wind turbine is to have a back up machine, I would naturally be using it also as a source of energy, even with the larger VAWT operating. The big VAWT won't make as much power as I can put to good use if one considers electrically generated heat for the house as an example of good use.
Last year I came up with a design for a HAWT which would be in the 2+ kW class to perform my backup requirement. I did not want to clutter my field with unsightly guy wires so a totally free standing tower was needed. Complicating the issue is that the finished system can have no foundation. It has to be stable merely sitting on the ground. This is to avoid permits and taxation issues. It needed to be tiltable to provide ground access to the turbine without climbing. It had to be a motorized tilt system that I could operate working alone. The tower had to be high enough to get the turbine into productive, non turbulent wind. My design will place the turbine hub at approximately 66 feet.
It has been an enormous amount of welding, especially making the prefab 20 meter long tiltable 'stick'. I made use of the inventory of 4-1/2" x 0.125" wall steel sprinkler pipe which I lucked across and also put to good use making the larger VAWT. A single pipe 21 feet long is very stiff, but I found when I had welded three lengths end to end that the finished pole had the rigidity of a well cooked piece of spaghetti. To fix this I welded a 12" x 12 " box frame around the entire length, tapering the frame the last 10 feet towards each end. The box frame consists of twelve, 1/2" diameter solid cold rolled steel rods running the length of the 63 foot center pipe. The surrounding box is welded to the central pipe every five feet through angle iron standoffs.
A substantial pyramidical shaped base frame was built with a solid steel pin at it's top where the tiltable tower will pivot 1/3rd up from the bottom of the tower height. A gin pole and 3/8" steel aircraft cable is attached to the tilting section to prevent tower sag and to assist taking the weight of the nacelle and blades during the tilt up or down operations. This drawing shows the basics of my tower design.
The second photo is an aerial shot of my work yard. You can see my ambitious VAWT , the Big Green Thing aka BGT is on the left. Look for the long white pipe that begins at the base of the BGT and ends part way along the barn building to the right. This is the 20m tiltable tower section and is where I fabricated that large weldment. This is the best photo I have which shows it's true length in some sort of perspective.
Last weekend with the help of a couple of friends I was able to relocate the tilt up tower section and the pyramidical base frame, now completed and painted, out to the field where this system will be set up shortly. I welded a set of car ramps upside down under one side of the base unit and these acted like skiis, enabling me to pull this weldment quite easily with my wheeled loader. My friend rode the beast like a large jet ski in my field, the wind in his hair and a wake left behind in the grass. See picture.
Here are a few more pictures of the relocation drill last weekend.
Here is a close up picture of the hinge point which accepts the solid 2" steel pin at the top of the pyramidical base tower.
I have some more detailed construction photos which I will post later. I need to re-size them first.
Nice work! How do you find the time to post?
I am always in awe when I see the things you do.
if i have said it once, i will say it again
your ambition is only surpassed by the quality of your build!
man dude, you are my hero! i have no idea where you get the energy to design, much less
drag all that iron together and then fabricate stuff as large as it is, and do it in such an appealing manner.
artistry in iron in my opinion.
me? i don't have that kind of energy or physical capability now, and quite frankly i am pretty sure i never did... wow.
that big machine, when you get it deployed makes me think i ought to put it on my bucket list as one thing to buy an airplane ticket to come and see.
i am not sure the average guy has any idea or is capable of fully appreciating the amount of work it takes to build such a machine.. holy crap it isn't like you can lay it all down on a bench and weld it all up in position. just the thought of climbing up there to get in some over extended position to hang on by the hairs of my teeth, with 40 plus feet of welding cable draped over my forearm, and then have the strength to keep a steady arc?
even if that machine never makes a kwatt/hr, it is as far as i am concerned one of the 8 wonders of the DIY world!
great work, i so look forward to seeing that thing turning out power on a youtube clip some day soon.
bob g
ps. i am equally impressed with the smaller unit.
Holy crap batman, that is some very impressive metal construction!!!
I have to agree with Bob ..... where do you find the time and energy ?
BTW, what's with the antenna farm ?
Thanx for the compliments guys! Bob, you are absolutely right about ordinary sheeple's inability to realize the level of detail and scope of this project. Consider also that in the case of that large BGT, VAWT, at no time during building it have I EVER had a second pair of hands on site to help lift this or hold that. Getting some of those pieces of steel wayyyy up there posed an enormous challenge. In some cases purpose built jigs had to be engineered. I'm close to completion of the four large airfoils which can be seen in that yard picture above. One has a skin of sheet steel pop riveted to it but the wrinkling was so bad I have to drill out some 300 pop rivets and find another way to do this. ??? Like you I suffer some physical problems and I have to push myself really hard to do this stuff. Getting old doesn't help either. When I started the BGT I was able to handle those 21 foot lengths of pipe by myself. This year I discovered that I am no longer able to carry them around the yard like I once could. I am so thankful that I started these projects when I did. Starting the BGT just a year or two ago would have been a total no-go.
Anyone who has tried to DIY a wind turbine knows how critical finding the right generator is to this task. Preferred are high pole count, low RPM, neodemium magnet based alternators. Some brushless AC servo motors used in CNC as machine controllers have been obtained by people like me, tilting at windmill types :D and used to good effect. Most of these servo motors are unfortunately high speed so gear boxes are necessary to increase the propeller shaft speed. In searching for suitable gearboxes in scrap yards and surplus stores for the entire past decade, I can tell you that they practically do not exist. Those that do are encased in very heavy cast iron gear cases, not optimized to hoist 60 feet in the air. If one is fortunate to find a slow speed PM servo motor, one has the ideal generator for a wind turbine.
I recently chanced across some 24 volt AC, 650 watt rated, 3-phase brushless wheelchair hub motors. I discovered that they can put out enough voltage to deliver 15.5 VDC to a 12 volt lead acid battery at just 200 RPM. At this speed they will charge that load at about 350 watts. It turns out that if one removes the mechanical brake and electric brake activation solenoid coil assembly from the back of these a hex shaped short shaft, normally used to engage the brake, becomes exposed. This stub is a perfect fit into a standard 6 point deep impact socket. I purchased three deep socket impact sets to get three of the required 7/8" socket size and make couplers out of them so that I can put four of these wheelchair motors in series on the same propeller shaft. My plan is to put a 3-phase bridge rectifier on the output of each individual motor and then wiring all four 15.5 VDC outputs in series to give me the charge voltage necessary for a 48 volt battery bank. If my turbine blade can achieve ~300 RPM, I should be able to reach my 2 kW power production target.
I attach some pictures of these nifty little motors. There are 44 NIB magnets inside an aluminum drum with a steel flux band on the ID of the drum and on the OD of the magnets. There are something like 48 poles in this motor. Cogging is very, very minor. With all three output leads shorted together the braking action is smooth as silk and very strong. With the brake components removed as I am using them they weigh in each at just 20 lbs.
I am now in the process of building the nacelle which holds the four of these in an inline stack. Before someone mentions it, I have arranged rubber compliance for every motor in it's three mounting bolts so that slight imperfections in the shaft alignment geometry does not end up wiping out the nice ball bearings in these very nicely manufactured motors.
The propeller shaft size is 1-1/8". I picked up a rather unusual find at the recycling place where I got these wheel chair motors a while back. It is a WW-2 fighter trainer propeller, 8 feet long. Just for fun I have manufactured a keyed hub so that I will be able to try this prop on this wind turbine. It is way too small however to make the power I am designing for. At 100 lbs it might be too heavy for my tower. For the 2kW+ power target I am shooting for I need to manufacture a 3 bladed propeller some 13 feet in diameter. The last photo here shows my airplane prop hanging off the front of the nacelle under construction. This is the closest sort of thing that I do nowadaze for actual fun. ;D ;D ;D
This entire project is very much being designed as a R&D test bed. Tilt up tower, etc. Even the furling system is research oriented. I decided against using one of those tail fin driven furling systems that rely on a balance between the system size and weight, and the propeller characteristics. To implement one of those you need to have the actual blade you plan to use in hand. I do not yet know what my blade weight will be. Furthermore, those mechanical jerk and flip furling systems are extremely hard on the turbine shaft and roots of the blades. I made the executive decision to power the azimuth axis of the turbine, pointing in or out of the wind, by smooth, precise electric motor control.
This involves a clever system I came up with that will employ a remote 3-cup anemometer tachometer generator to give me a wind speed related rising voltage. That voltage will drive a small 28 volt gearhead motor to rotate a plate with two micro switches on it against a spring. This switch assembly will in this way be rotated from 0-90 degrees around the bottom of the shaft of a small wind direction sensing vane located on the back of the generator nacelle. This free wheeling tail fin will always head towards the direction the wind is blowing. The closure of the microswitches on the rotating plate will command the DC gearmotor that turns the nacelle in azimuth. One switch closure makes the system turn CW until it lines up with the null point of the vane switches. The other switch closure makes the nacelle turn CCW until the same null point is reached. As wind direction changes, this will cause the nacelle, and thus the turbine propeller to follow it. If there is low wind, the position of the rotating plate upon which the microswiches are mounted is aligned so that this null is directly in line with the nacelle pointing direction. If the wind is at a high level which adjustments have determined is where the blade must be fully furled, then the tachometer generator will make a voltage sufficient to rotate the switch plate against it's balance spring to place the null of the microswitches at 90 degrees to the nacelle pointing direction. In this instance the nacelle will do an azimuth move and stop moving when it finds the new null spot where the tail fin is pointing 90 degrees off the pointing of the nacelle. The beauty of this system is that it can be calibrated to do smooth partial furling automatically so as to keep the blade at max power point despite winds that would normally be the cause of full furling. I hope I was able to describe this concept clearly enough. I plan to use mosfets between the microswitches and the DC azimuth drive motor. In this way, due to the high Z of the Mosfet gate, I can add some integration capacitance to smoothen the response of the azimuth drive to ignore short turbulent gusts and only concentrate on the actual trend. This and the electric drive ought to go a long way towards relieving my (likely DIY) blades of destructive stress and overspeed.
In answer to a question from Jens. The antenna farm is my astronomical radio observatory which I have been building here as a back burner project. I hoped to end up with a community teaching resource for high school and university students in physics, astronomy, computer programming and electrical engineering. I've brought it a long way by myself but require actual grant funding or help from a philanthropist to get it over the hump to fruition. The dish antenna in my avatar is on site here now awaiting my attention. It will make a very nice radio telescope. This project is looking less likely to happen as the world implodes financially. This project represents a lifetime of struggle. It is Big Picture stuff. The wind turbines are just pieces of the infrastructure part of that bigger picture. I have always believed that lack of funding was not a good enough excuse not to proceed with the really important pursuits of intellectual mankind. Astronomy is arguably one of those really important pursuits. With the wind making electricity here, having to come up with money for electricity is one less funding requirement standing in the way of tuning in on the cosmos. One less barrier to DISCOVERY! 8)
BTW, there is a discussion about high pole count pancake generators along the lines of the wheelchair motors I discuss here at this link. http://www.microcogen.info/index.php?topic=2800.0
In this other thread I first learned the term "wound in hand", referring to the number of paralleled conductors would in a motor slot to facilitate the mechanics of winding in tight spaces and tight radius turns that are impossible to accomplish with really large magnet wire sizes. For anyone interested, the wheelchair motors I have described are wound with '6 conductors in hand'. You may be able to see this in the photo I provided.
First off I like the tower base solution to a non guyed free standing tower the pyramid looks to have a nice height to ground coverage ratio plus you have the capability to position several heavy blocks of concrete or other weight on the base structure to add additional stability if needed. The tower? well its a tower that looks like an artwork befitting to the rest of the structure, and should be quite suitable for your turbine. If latter you find you need taller or stronger you can always change it out.
your Assembly for your generator is so far first rate as far as I can see with one exception that I see. and this could be due to the incomplete status of your assembly. I will not try to second guess that.
But the one thing I noticed (and again bare in mind I don't know where your thoughts are.) it has to do with the shaft for the Turbine. From what I can see you have 1 bearing on the shaft and it looks like you will be using the generator hub itself as the 2nd bearing That worries me unless you have plans to place a second support bearing further out to nullify any loading in the generator. or the coupling
Another thing I was thinking was if you were to relocate the turbine shaft above the nacelle then use a cog belt drive you could put a large sprocket on the turbine shaft and a smaller one on the generator shaft . You could then also use a hollow turbine shaft as well and add in an active and even a passive pitch control This would also allow you the possibility of using a much larger diameter turbine blade setup if need be, and you might even see that your generators could produce 3 or even 3.5 KW or more if you additionally added in forced fan cooling
Quote from: Frank S on September 02, 2012, 02:23:36 AM
First off I like the tower base solution to a non guyed free standing tower the pyramid looks to have a nice height to ground coverage ratio plus you have the capability to position several heavy blocks of concrete or other weight on the base structure to add additional stability if needed. The tower? well its a tower that looks like an artwork befitting to the rest of the structure, and should be quite suitable for your turbine. If latter you find you need taller or stronger you can always change it out.
your Assembly for your generator is so far first rate as far as I can see with one exception that I see. and this could be due to the incomplete status of your assembly. I will not try to second guess that.
But the one thing I noticed (and again bare in mind I don't know where your thoughts are.) it has to do with the shaft for the Turbine. From what I can see you have 1 bearing on the shaft and it looks like you will be using the generator hub itself as the 2nd bearing That worries me unless you have plans to place a second support bearing further out to nullify any loading in the generator. or the coupling
Another thing I was thinking was if you were to relocate the turbine shaft above the nacelle then use a cog belt drive you could put a large sprocket on the turbine shaft and a smaller one on the generator shaft . You could then also use a hollow turbine shaft as well and add in an active and even a passive pitch control This would also allow you the possibility of using a much larger diameter turbine blade setup if need be, and you might even see that your generators could produce 3 or even 3.5 KW or more if you additionally added in forced fan cooling
Frank,
Thank you for your valuable comments. It sounds like you have a fair bit of experience with these machines. That drawing is impressive. Did you make that?
First off, The pyramid base has five base bolt down plates at the OD. See picture. The plan is to have a cement plant custom pour me five, 2' x2' x 4 ' cement blocks with a weldment inserted which I will provide which has significant rebar welded up inside and a substantial steel plate to end up being centered on the top of the block once cured. I will weld a 1-1/8" bolt to each block and the turbine base frame will bolt down to these five blocks which themselves sit on hard clay layer exposed just 10" below my excavated topsoil. I have been welding up the rebar assemblies for the past three days. I hope to have these foundation weights delivered and in place late this week. Since delivery will coast me $300 and the truck can carry more than the five blocks I need for this job, I am also making four extra weights to be used as extra ballast for the BGT. So... the pyramid frame seen in these pictures will actually be sitting over a foot above the grass level perched on what will look like rectangular concrete foundations, but could be relocated with my loader and a fair bit of work down the road if necessary. It still qualifies as just 'sitting on the ground, no foundation and is movable'. With each block weighing over 2000 lbs, and the generous footprint, I will sleep well enough comforted that the tower will be resistant enough from blow over.
Your concern about the first generator being used as the rear bearing for the propeller shaft troubles me. I figured I was going to be OK with this plan. The wheelchair motor has two fairly substantial bearings in it close to each other. This would be seen for practical purposes as a single, beefier bearing to the rear of the prop shaft. I attach a close up photo of the back of one of the generators with the brake section removed. It shows one of the bearings and the six sided shaft I use to couple to the following unit. I could add an additional front nacelle bearing, just like the beefy single flange block bearing now employed ,but this would set my propeller farther forward than I had counted on from a nacelle balance point perspective. I'm going to give this some serious thought. If I am going to make a modification like this, now is the perfect time. The front bulkhead of the nacelle is all 1/4" steel so it is heavy enough to handle such an add-on.
I like the idea of a speed up with toothed belt but do not want the extra weight and the extra complications building weather covers. I am also not funded for purchasing such components. That pair of pulleys and a belt could set me back $500. I just cried hard because I had to purchase a new 80 tooth, #50 roller chain sprocket (16" diameter) for my azimuth drive system because the one I had tried to use from a scrapard was too worn out and the chain kept binding. This was $135 not planned for. We in Canada sure have to bend over hard to buy hardware up here. I am going to fly it initially direct drive as planned.
The higher speed would be attractive as it would produce increased voltage. At the same amperage the I2R losses of the windings would make no more heat than normal so a speed increase would be a legitimate way to get more wattage out of these units without overheating. I have the opportunity of rewiring the outputs of the four bridges to say series parallel to accomodate a doubling of produced voltage if I need to. Increased voltage would not be bad anyhow because it would possibly lower the wind regeime that the wind turbine could charge a 48 volt bank in without having a step up capable charge controller. I will have to address a charge controller once the turbine is up and running.
The thing that caused my concern is having the coupling between your 2 most important bearings on the whole project. That coupling even if it were a pressed fit is a potential flex joint. if there is any way to place 2 bearings on the same shaft even if they are back to back one being inside and the other outside then the moment would be canceled out instead of being transmitted through the coupling.
you 14 or 14 ft diameter turbine will create a huge gyroscopic force this in turn is translated into the shaft which becomes a moment of inertia perpendicular to the shaft. Even if a shaft has a slight amount of flex as long as it is not an accumulative fatigue stress that builds up in the shaft is would not be a worry. but transmitting the moment through a single bearing into the coupling will eventually cause the coupling to become loose and fail.
If you have a Dial indicator and a way to clamp it to you framework set the indicator point against the shaft next to the red coupling then try to move the end of the shaft up and down take note of the movement.then use your air plane prop install it on the shaft and try to move the tip of one of the prop blades at rt angles to the shaft and the indicator take the readings again note how much different it is. and know that the prop has no way near as much leverage as the tip of the turbine blades will be.
As far as the drawing I posted that is just a part of a 5 to 30 KW generator that I am designing I have the stater the cooling fan the rotor and a lots of other stuff suppressed out of the picture for clarity to show the principle of the pitch control concept. The design that i have been working on could have either internal or external stater direct driven epicyclic gear driven or as shown belt or chain drive but I am dealing with the prospect that the turbine blades might be upwards of 20 meters in diameter or larger. depending on what wind zone it might be mounted in.
And no I do not have any RE power at this time my last wind machine was a Chrysler 105 amp Alt re wired and modified for 9 ph mounted on a sail fan like a water windmill. as an experiment over 30 years ago
Quote from: Frank S on September 02, 2012, 02:38:13 PM
The thing that caused my concern is having the coupling between your 2 most important bearings on the whole project. That coupling even if it were a pressed fit is a potential flex joint. if there is any way to place 2 bearings on the same shaft even if they are back to back one being inside and the other outside then the moment would be canceled out instead of being transmitted through the coupling.
you 14 or 14 ft diameter turbine will create a huge gyroscopic force this in turn is translated into the shaft which becomes a moment of inertia perpendicular to the shaft. Even if a shaft has a slight amount of flex as long as it is not an accumulative fatigue stress that builds up in the shaft is would not be a worry. but transmitting the moment through a single bearing into the coupling will eventually cause the coupling to become loose and fail.
If you have a Dial indicator and a way to clamp it to you framework set the indicator point against the shaft next to the red coupling then try to move the end of the shaft up and down take note of the movement.then use your air plane prop install it on the shaft and try to move the tip of one of the prop blades at rt angles to the shaft and the indicator take the readings again note how much different it is. and know that the prop has no way near as much leverage as the tip of the turbine blades will be.
As far as the drawing I posted that is just a part of a 5 to 30 KW generator that I am designing I have the stater the cooling fan the rotor and a lots of other stuff suppressed out of the picture for clarity to show the principle of the pitch control concept. The design that i have been working on could have either internal or external stater direct driven epicyclic gear driven or as shown belt or chain drive but I am dealing with the prospect that the turbine blades might be upwards of 20 meters in diameter or larger. depending on what wind zone it might be mounted in.
And no I do not have any RE power at this time my last wind machine was a Chrysler 105 amp Alt re wired and modified for 9 ph mounted on a sail fan like a water windmill. as an experiment over 30 years ago
Frank,
Yes I have a dial indicator or two. You have convinced me on the need for a second front shaft bearing. I'll see what I can come up with and post back here about my plan. Thanx for your valuable input!
That design you are working on is very precisely documented. When I toss parts together I seldom have anything more detailed than the rough sketch of the tower I posted above to work with and what is in my head. My hands usually know what to do. Obviously that approach doesn't work when others are involved in the manufacture of components for the system as appears to be your case.
I was thinking about the balance issue introduced by moving the propeller forward. It turns out I have a fifth wheelchair motor which wouldn't be a lot of work to add at the rear of the nacelle frame since the back section is not completed yet. This is attractive from the 20% cross-the-board gain I'd get in system output voltage. I worry about the weight I'm putting up there though.
Regarding my tilt portion of the tower. I don't see ever needing to make it taller. As for strength, it will have to do as is. I have so many other projects on the go presently and then planned that I just need to get this system up and running as quickly as practical. If the tower is happy with the weight and looks like it could handle say 100 lbs more then maybe later an upgrade to a belt speed increase as you suggest could be performed. This would enable a slightly larger prop to be used to good advantage. Perhaps a 14-15 footer. After this one is running I have to direct my full attention back to completing the main BGT VAWT system. FYI, that system has a swept volume of about 45 square meters (rectangle seen by the oncoming wind).
Back in the days when I was a one man show and anything I did in my factory was pretty much up to me as long as I could put food on the table and keep the bills paid. Now I am part of a much larger corporation I still do as a darn well please but every square foot of floor space is valuable so I don't have my off the wall project space like I used to have. plus with 50 to 60 workers on the floor if I were to start building something all of them would want to try and stand around to see what I was doing. Neither I nor the company can afford for that to happen. Most of my time is tied up in designing products and ongoing projects, so I do 90% of my prototyping now on my computer.
Not like the old days when I sat down with a customer and sketched out a design for a 16 ton cap freight elevator with a 4 story rise on a couple of table napkins and managed to convince him to hand over half the price of it in cash with the contract being one of the napkins.
I just discovered this thread.
Amazing! I wish I had the time to experiment with such projects. These are the things that really interest me. Nice job!!!!!!
Here in South Florida, not much steady wind, but plenty of solar.
Project Update.
I have been really working my tail off trying to get this tower up on the custom concrete blocks. As of last Friday we have liftoff. Thanx to an electric winch I was able to achieve my very first erection of this 20m tilt up tower!!!! 8)
I used to work with video and I know that a picture is worth 10,000 watts. ;) Here's a photo essay of the past weeks efforts which ought to represent some real watts fairly soon down the road. Enjoy.
more pics...
and more pics...
and still more...
So now that the tower is at long last in place and the tilt works I have two immediate issues to deal with. Need to upgrade my electric winch. The one I used is too small and continued use would be very risky. The straight section that tilts is very top heavy now even with the lowest section, the part below the 'pin' filled with cement. I need to fabricate about 700 lbs of bottom counter weight to compensate for the tower and the extra weight that the turbine nacelle and blade will add to the top.
Once that is done I have to finish running the electrical wires on the tower and add three electrical boxes. Finally I need to finish the nacelle and blade fabrication, and the spinning 3-cup annemometer system that will sit on a short horizontal stub tower sticking out of the vertical tower below the main turbine blade. The wind signal sensed by this annemometer will be used to proportionally turn the main propeller into and out of the wind, an automatic means of controlling the amount of power the turbine blade receives depending on wind conditions. Some folks will call this auto furling. Lots of work to do yet!
holy crap! RCA you da man!
what a project! and it is coming along very nicely.
i have no idea where you get the energy for such an ambitious project.
let alone the motivation :)
great job, i am impressed.
bob g
In the plan for a foundation substitute I came up with the idea of hiring a concrete plant to cast custom re-bar weldments that I made with an 8"x8" x1/2" steel plate on the top surface into some 2x2x4 foot blocks. Each block weighs about 2500 lbs. I welded a 1-1/8", high grade steel threaded rod onto each plate to be used to mount the tower the way municipal steel light poles are mounted. Earlier in the photo essay I showed me unloading one of these blocks from the float trailer on which I had nine of them delivered. Five are used for this project. The other four will be used to add extra ballast to the bottom of the larger BGT VAWT.
The topsoil has been removed only enough to expose the firm clay layer upon which the blocks were precisely placed after levelling the holes.
I had a lot of trouble finding a cement plant that was willing to work with me on this custom project. Fortunately I did find one and they also gave me a great price of just $40 per block. Delivery was $300 however and then there was also full taxes to pay. The threaded studs were over $30 each and the nuts about $5 each. We sure pay through the (select most abused body part here) in Canada for quality hardware for DIY projects.
Quote from: mobile_bob on October 15, 2012, 08:41:12 AM
holy crap! RCA you da man!
what a project! and it is coming along very nicely.
i have no idea where you get the energy for such an ambitious project.
let alone the motivation :)
great job, i am impressed.
bob g
Thanx Bob! I have to admit, this project turned out to be a lot more work than I originally invisioned. It has taken me pretty much two years so far to build. This is time taken away from finishing the larger, much more ambitious BGT that must get done next. I don't see any rest time on the horizon just yet. Sure will be nice the call I make to Hydro to tell them I no longer need their obscene power bill delivered to my mailbox every month. That day IS on the forseeable horizon now! ;D ;D ;D
DIY Rob
aka rcavictim
WOW!!! :o
RCA,
I must say I had my socks blown off seeing what you accomplished. Very nice indeed.
Hoping for good weather for you.
Please be safe.
Henry
RCA
Man.. you amaze me! Good Job, Nicely done.
Your creativity and ability never cease to amaze me.
Rob
Awesome job there RCA. Amazing what will determination and talent can do despite a physical handicap. Inspirational!
Wow. NASA could use that as a launch tower too !! but since we have nothing to launch anymore, best to use it to generate power.
(I've now been officially laid off, and living in a scrapwood cabin while my new house is being finished, seeing as this great country of ours has to buy seats on Russian craft, to get to orbit. Even Red Bull flies folks higher than NASA can. )
Hi guys. I continue to build the components that will soon adorn the top of my 20m tilt tower. When I had just completed fabricating the frame that can hold up to eight, 100 lb. precast cement patio stones to act as an 'adjustable' counterweight at the lower end of the 'stick', I took a video of the day I tested the motion of the system. It appears to work AOK! :)
Enjoy.
I made the decision that I would fabricate slip rings into the Yaw or AZimuth drive platform under the nacelle so as to avoid problems with tangled wires and potentially catching the loop of cable with the turbine blade one day. That would have put a quick end to the whole experiment! Because my AZ is powered by an active, DC gearmotor driven control system to seek the wind, measure it's strength and turn the turbine blades in or out of the direction of the oncoming wind at an increasing offset angle as winds climb, in order to continue to be able to harvest power rather than merely flipping the turbine out of the wind as so many small HAWT's do, I had quite a fabrication task ahead of me. I required a total of six circuits from the ground to the rotating nacelle. A large flat custom slip ring assembly with ten carbon brushes was fabricated from scratch. This 'package', which will slip onto the end of the tower and secure by tightening four, 3/4" bolts, just took me a whole 3 months to fabricate. Picture essay follows. The slip rings are fabricated from 1/8" thick yellow brass cemented to a 1/4" thick Glastic (electrical fiberglass) disk insulating them from the 80 tooth, #50 roller chain AZ drive sprocket. The two heavy power rings each are attached at approximately 120 degree points and heavy brass lugs permit three #8 copper wires of equal length to go to the nacelle, equalizing the current in the rings. There are three heavy duty carbon brushes riding on each of the heavy power rings with equal length #8 wire from each brush holder to an output terminal which will hook to the #2 AWG aluminum cable which runs about 500 feet to the basement of the house. I expect to see as much as 50 amps flowing through the power brush set. Since the shorting contactor will be on the earth side of the rotating joint, I required as much reliability and redundancy in this conductive path as I could manufacture. Not being able to 'lock the rotor from overspeed' is not an option, ever, period. If the automatic system fails or if I get nervous before it activates, I will have the option of shorting the generator from the house with the flick of a switch.
This command also engages the 'automatically seek 90 degree pointing away from the wind direction and park there', system.
More pics of AZ drive and slip ring assembly.
Here are some pics of the DIY blades. Blade attack angle will be subject to 'tune for best performance once installed', and is adjustable and can be locked. Turbine diameter 13 feet.
Stainless nose cone is a wok cover from the dump, has been sandblasted and painted white. I am the Master of Repurpose! 8)
The blades are cut out of a 1/2" wall heavy 8" ID water main PVC pipe. PVC is heavy, brittle, and not very strong. The centrifugal forces on a 12 pound blade at 250 RPM exert over 500 lbs at the hub. I have NEVER seen anyone make PVC blades anywhere near this large. To try to get them to survive I have imbedded a 3/4" wide X 1/8" thick,, mild steel strip down the length of each blade buried in a machined slot. There are a dozen 1/4-20 countersunk bolts tapped, screwed through the blade from the back (convex) side and welded to the strap, each bolt at about 6" spacing. Two grade 8 bolts secure this strap to the metal bracket at the hub. The force of the oncoming wind will put the strap in tension and the PVC blade in compression.
The surfaces, despite the embedded steel spine and bolts, is smooth. Much work went into these to save the $500 cost of ordering a set of Chinese made fiberglass blades out of a dealer in Texas. I hope to be able to order a set of those anyhow as they would likely save the day down the road as needed spares. Still, I am plowing ahead into uncharted territory making PVC blades this big and being all DIY'able this is valuable R&D that others can potentially benefit from.
PVC is difficult to get paint to stick. I sanded it, cleaned well with acetone and also lacquer thinner (couldn't find a can of lacquer thicker) Ha ha :D , and painted the blades with some white automotive lacquer. That gave a surface that my red enamel for the racing stripes could adhere to. This will look pretty when it first goes up but I have a hunch that the leading edge of the blades from the impact of wind, rain and molecular collisions will make the blades show their true blue colors in time.
Cheers!
Rob
Are you going to power a city with this ?
Quote from: mike90045 on February 10, 2013, 08:03:36 AM
Are you going to power a city with this ?
Go ahead, mock me. ;) As far as I'm concerned, the cities, bless them, are on their own. I'm on a
private power trip out here.
I continue to be alternately gobsmacked and speechless by this project...
There is some exquisite work going into this HAWT, the scope and sheer size of the thing would challenge a well-equipped team, let alone a "man in his shed".
BTW, I don't think Mike was mocking you, I think he was just impressed at the scale I am too... Just how many watts to you anticipate making from this thing? (assuming a sensibly windy day)
Quote from: AdeV on February 10, 2013, 02:47:29 PM
I continue to be alternately gobsmacked and speechless by this project...
There is some exquisite work going into this HAWT, the scope and sheer size of the thing would challenge a well-equipped team, let alone a "man in his shed".
BTW, I don't think Mike was mocking you, I think he was just impressed at the scale I am too... Just how many watts to you anticipate making from this thing? (assuming a sensibly windy day)
Ade,
I didn't think Mike was mocking me, hence my winky. This machine is the hardest ~2500 watts I'll ever work for. With a proper slow speed gen head in the nacelle, not repurposed wheelchair motors strung together, and a real 14-15 foot commercially sourced fiberglass prop I could add a kW within the strength of the tower I suspect. Not having guy wires is a weak link. I don't like the way guy wires makes a large part of your field useless. Working mostly alone pretty much dictates a tilt down system as I have designed. I'm really pleased and proud of how it looks.
The BGT definitely represents the hardest 10-15 kW I'll ever work for. The good news is on that one, according to a professor of mechanical engineering at McMaster University who looked at my design, it should make 10 kW in a "not so big wind". I need to get back on that project seriously this summer. I am so close to completion now.
Thank you friends for your keen interest and moral support. I truly appreciate it. I've really been dragging lately and having trouble getting this done. Hope I gain some momentum in the spring, winter is such a terrible, depressing time for me.
Cheers,
Rob
I saw and understood the wink. OMG ! you didn't abandon the giant VAWT, and re-purpose it's guts, you are building and 2nd turbine !!! You got 2 cities you plan to power, or do you just like redundancy with a second mode of backup?
Quote from: mike90045 on February 10, 2013, 11:31:52 PM
I saw and understood the wink. OMG ! you didn't abandon the giant VAWT, and re-purpose it's guts, you are building and 2nd turbine !!! You got 2 cities you plan to power, or do you just like redundancy with a second mode of backup?
Hi Mike,
Where I live, if my BGT VAWT fails in January it will be five months before I could get to do any repairs. I hardly ever even blow snow off my driveway because that represents hard outdoor winter work which my body has told me specifically to not ask for. That would be four months or more without a source of power except diesel. Not an option. I decided a smaller backup wind turbine was absolutely essential to my off-grid plans, so....
The BGT was taking so bloody long I figured a smaller, simple, HAWT could be whipped up in short order. Well, nothing I do can ever just be whipped up in short order. This smaller backup turbine has been a 2+ year time sink at this point, but it is almost done.
Just before this past Christmas I scored a super deal on 5.5 kW of solar photovoltaic panels, 21 pieces of 265 watt panels new for 46 cents a watt. I didn't hesitate too long to pull out my credit card. I hope to drop everything else I'm doing as soon as the weather is warm enough and install these. Wow, what a wonderful complement to my off-grid power plans here! ;D All I need to make this subsystem a go is a MPPT charge controller for my 48 volt battery bank/inverter now installed and ready.
Cheers,
'I'm on a power trip' Rob
Here is a video showing the active azimuth drive system under test.
Time for an update on progress with my DIY HAWT project. Last fall I managed to get the DIY, 20m self standing, power tilt up tower installed in my field. Took me two years to build that tower. Just sits on the ground, no foundation, no guy wires, NO PERMISSION, NO INSPECTORS, NO PERMITS. ;) During the winter months I was able to fabricate the power azimuth drive platform with slip ring assembly, the nacelle containing the four repurposed, neodemium magnet, brushless , 3-phase, 24 volt, 650 watt AC wheelchair hub motors which are mechanically ganged on the propeller shaft with no gearbox. The 3-phase output of each individually is turned to DC with a beefy bridge rectifier, boosted with an electrolytic capacitor and then all four DC sources are wired in series to obtain max voltage possible output. This runs about 500 feet one way to the house through #2 AWG aluminum and #4 AWG copper cable. Loss will be negligible at 60 volts and 40 amps.
I managed to fabricate the sensing tail fin system that uses wind direction against the fin to activate one or other of two microswitches which relays drive commands through a buffer and time delay circuit to the AZ/YAW DC gearhead motor. This sysetm keeps the turbine tracking straight into the prevailing wind direction.
To take advantage of a power AZ capability as a substitute for power controlled blade pitch, I have also set a large format 3-cup weather station tachometer on an extension arm located below the main turbine propeller. The 3-cup spins a beefy 72 volt PM, with brushes tape drive motor. This has been feeding a 12 volt neon automotive light in my house basement all winter, reaching full brilliance on many occasions when the winds are elevated. The power from this tachometer generator is used to power a small 28 volt PM brushed armature gearbox motor from a peristolic pump salvaged from a refreshment vending machine. This gearmotor is able to wind up a spring coiled around a shaft which is allowed to rotate up to 90 degrees. The microswitch plate is mounted on this shaft. When low winds are present the microswitch 'zero point' ( i.e. both switches open circuit) to the wind vane is in line with the nacelle pointing at the wind direction. As the 3-cup starts to spin, it generates rotation against the spring on the microswitch plate creating a new 'zero point' which the AZ motor is commanded to maintain in reference to where the wind is holding the direction vane. By this technique there is an increasing offset nacelle pointing angle to the oncoming wind introduced by this control system. When the winds are dangerously high, this system will keep the turbine propeller at 90 degrees to the prevalent wind direction, and if that dangerous wind changes direction the 90 degree to it null pointing will be actively maintained. A further function of the 3-cup wind sensor it to activate a shorting relay which shorts the generator output whenever the blade is commanded to the 90 degree out of wind offset.
Is anyone following this? ???
So this just past Saturday I had a couple of friends over and between the three of us we managed to get the top package out to the field from the shop and installed onto the top of the tilted down tower. All the cabling, already in the tower from last year was terminated to the top package, propeller was bolted on, the wrong way at first, but unlike NASA and the Hubble I caught the mistake before we flew it. ;D The top package with blade weighs about 350 lbs. I had to add a total of 500 lbs in 100 lb. concrete patio stones as counter balance at the bottom to make the system work properly. I could probably add yet one more patio stone to the mounts I fabricated at the bottom of the tilt tower to receive as many as 8 of these. The 12 volt electric winch is handling the job like a champion right now, so no worries.
I have uploaded two videos to Youtube. One showing me and friend installing the propeller incorrectly after which I had to go fetch the nosecone which was needed to determine the lock down position on the shaft for the prop. During that walk back to the shop it occurred to me that we had just placed the blade wrong side out. :o A friend who installs wind and solar for a living tells me people make this mistake all the time. As he puts it, it is during the champagne moment that one has to tell folks it is a downwind turbine! :D
https://www.youtube.com/watch?v=hUEX6yYqG6k
https://www.youtube.com/watch?v=inm-YjwtF6I
I took still pictures of the work yesterday. I'll post them when I get a chance to shrink them first.
I still have to fabricate the electronics control package that will live in the weather tight electrical cabinet now in place at the base of the tower. That won't take long. Where I have just arrived is almost the Champagne Moment, so this weekend represents a huge milestone marker for this project.
The damn thing is finally UP! :) 8) 8) 8) 8) 8)
Regards,
DIY Rob
edited to correct typo. I don't have a 'hose basement'! :D
Following with interest, yes.
Yours is a self monitoring. self-correcting "upwind?" turbine.
A local fellow here built an actual downwind turbine. Got real cranky after suckered on dumping a few hundred grand into his project for the feed-the-grid for $'s Myth.
They did not want his power. He could not force this no matter how long he tried, and how many of thier compliance $'s hurdles he would jump over.
I've alway'd been curious how this thing turned itself for protection with changed wind directions and forces. I've actually seen it head direction rotating recently. Haven't seen it ever spinning/producing though for years. Locked rotor. It never looked like it had blade feathering? capabilty at the small center hub.
Ah . . . he does not respond to questioning. Greets would be visitors with a shotgun now. Bitter, bitter man now. He'd be a happy man now if he'd just been building smaller with far less bucks out for just personal self-sufficiency power.
What I have discovered in the woodgassing fueling area also - - WHY; and for WHO a fellow is developing/building if far more important than the actual system for sucess satisfaction.
Thanks Mr Rob. Now I know how it's doing this rotating turning.
Regards
Steve Unruh
Here are a few construction picture you guys haven't seen yet of the nacelle.
Here is the microswitch assembly that is modulated by a finger on the direction sensing tail fin. This plate is rotated up to 90 degrees as described in previous text by the wind strength related power from the 3-cup anemometer on the same tower.
The rest of the photos show how I can still get it up these days. :D
And here it is UP!
The nosecone on the prop is a cooking Wok stainless steel cover sandblasted and painted white. Found it at the local landfill site. I am truly the master of recycle and repurpose.
The propeller shaft is 66 feet above grade in nice clear, low turbulence air. I have an excellent siting for this turbine.
You can view a test I did spinning the pack of generator heads in the shop. Since the test I did pack high modulus of elasticity silicone sealant into all the clearance fit motor mounts and let cure for two weeks undisturbed. It now runs silently and there should not be little piles of metal particles accumulating under these moving motor mount bolts.
https://www.youtube.com/watch?v=n9t2xm57t34&feature=endscreen
Quote from: SteveU. on May 06, 2013, 05:34:54 PM
Following with interest, yes.
Yours is a self monitoring. self-correcting "upwind?" turbine.
A local fellow here built an actual downwind turbine. Got real cranky after suckered on dumping a few hunderd grand into his project for a the feed-the-grid for $'s Myth.
They did not want his power. He could not force this no matter how long he tried, and how many $'s hurdles he would jump over.
I've alway'd been curious how this thing turned itself for protection with changed wind directions and forces. I've actually seen it head direction rotating recently. Haven't seen it ever spinning/producing though for years. Locked rotor. It never looked like it had blade feathering? capabilty at the small center hub.
Ah . . . he does not respond to questioning. Greets would be visitors with a shotgun now. Bitter, bitter man now. He'd be a happy man now if he'd just been building smaller with far less bucks out for just personal self-sufficiency power.
What I have discovered also in the woogassing area also - - Why and for Who a fellow is developing/building if far more important than the actual system for sucess satisfaction.
Thanks Mr Rob. Now I know how it's doing this rotating turning.
Regards
Steve Unruh
People really ought to learn that the government has deteriorated into a massive POS that is only there to sucker punch them. Many farmers in Ontario got burned trusting in the government's promises about their FIT program. I have a friend who sells and installs small wind, or make that tiny wind, and solar systems. As far as having a grid tied system, his favorite line is "Anyone who spends $80,000.00 on solar panels and has no electricity when the grid goes down is a special kind of loser!"
As you know, downwind turbines are inherently self tracking. It would take a motor to pull them around out of the wind. This would take energy to do. Big problem with downwind turbines is the shadow of the tower causes significant thumping stress on the blades as they move in behind and then back out of the shadow of the tower.
i have a long history of stating point blank
"i would never produce a single solitary watt of power for sale to the grid"
it has far higher value to me, even if i don't need it just then.
utility companies produce power very inexpensively, even if they charge a higher amount.
and they don't like messing with inputs from other sources, and they really don't like competition from any source, big of small.
the only way a small producer can make a dime in this game is with government subsidies of some sort, and as we all know, what the government gives it surely can take away.
bob g
You've got some real kinetic art there! We've got one of those 8' decorative windmills in the back yard and I've spent hours (perhaps to many) watching which way and how fast the wind is blowing.
Quote from: Tom on May 07, 2013, 10:40:06 AM
You've got some real kinetic art there! We've got one of those 8' decorative windmills in the back yard and I've spent hours (perhaps to many) watching which way and how fast the wind is blowing.
Thanx. yes, I think this is a pretty neat looking piece of yard sculpture! Looks more advanced than the big pile of cow manure that my neighbor across the road has in his yard after clearing out his barn with a bobcat and then leaving it there for months. This would be the same neighbor that physically assaulted me because I do not waste my precious time and energy cutting my front lawn.
Well, been quite a while since I posted an update. Have not been at all well this spring and summer. Haven't been able to engage in any work at all. Thank goodness I got the nacelle and active azimuth platform built last winter and then installed and up this spring with the help of friends! I have been puttering away as able for several months trying to get the electronic control system that will manage the turbine over different wind conditions built. I have finally finished this mission critical component. I went with basically relay logic and various DIY function modules that plug into octal relay sockets. Some provide TD functions, another is a PWM speed controller for the AZ drive gearmotor, another senses windspeed and points the turbine proportionately out of the oncoming wind. When storm strength winds are detected it stows the blade 90 degrees to the wind and applies a two stage short to the generator output. I don't wish to overtorque any weak links in my powertrain trying to slam on the brakes. If the wind direction changes during stow, the system actively keeps the blade pointed 90 degrees to the wind. I gave the logic 12-1/2 minutes after a stow to 'take another look' at windspeed. If the storm front has passed by then the system resumes normal operation. If dangerous winds are still present it stays stowed for another 12-1/2 minute cycle.
This would have been better served with a PLC, but I am old school and haven't learned this newfangled stuff yet. At least I didn't employ vacuum tubes! Ha ha. ;)
Only had one wiring error that was easily discovered. Remedy was to move one wire on a relay socket to a different terminal on the same socket.
A week ago I placed an order for some commercially manufactured fiberglass composite wind turbine blades (made in China) and they are supposed to arrive at my door by end of today. The DIY blade I made so pretty out of steel reinforced PVC pipe worked like gangbusters but would have littered the yard if it had been allowed to overspeed. Additionally, it was not capable of spinning as fast as I need this turbine to spin to make full power. I'll sleep better knowing my blades are speed safe. I had the luck of selling some Hi-Fi gear recently which was able to fund my blade acquisition. It was quite a large chunk of change, because I had to ship in from the US. The border doubles the cost of anything I buy from the US. Free trade my ass!!!! >:(
Need to make a new hub once I have the blades in my hands. Maybe I'll finally be making power within the week.
This has been three long years in the making.
I have solar panels to put up next and need a summer to build a tracking frame for them. Doesn't look good for this year now. :( Then I need to get back to finishing the larger BGT VAWT.
Cheers,
Rob
I was able to get the custom hub fabricated over the past couple of days and yesterday was able to install the new set of blades. There was a period of break in the total calm where a small wind came up and the blades took off running. Looking good so far! 8)
Had problems with a tower lifting winch that was dead in the water. I don't have much luck with electric winches. Every single one that I have located outside gets fuck*d up and dies from all the rain we get. This one was no exception. I managed to figure out that the brush gear has gone to poor contact and by whackiing the end of the motor I was able to get the tower to the seat backs in the upright position. All the brand new galvanized wire rope I bought and have had exposed to the elements is starting to rust badly in less than a year. WTF? >:(
Anyhow, I am an old fart now but here's proof that I can still get it up! :D
Just a bit of work now on the completed controller to shake out a glitch (occasional false trigger of the braking sequence from a circuitry surge) and then I can install it once we get a suitable work day. Today is a nasty, hot and sticky humid stormy day so this will be a good opportunity to work on the controller in the comfort of the lab. I hear lightning cracking on the AM radio right now getting stronger. To tame this glitch I think I need to sprinkle a few ferrite core donuts here and there. Maybe a bypass cap as well.
Almost there!
Rob
Here is a close up of the business end with the new blades installed.
Beautiful work! my hat is off to you and all your efforts on this project.
i do have a question though, mainly because i can't tell on my little netbook screen
it relates to the blades... the side facing the wind...
are the blades mounted where the convexed side is facing the wind? or the concave/flat side facing the wind?
bob g
Quote from: mobile_bob on September 02, 2013, 11:26:00 AM
Beautiful work! my hat is off to you and all your efforts on this project.
i do have a question though, mainly because i can't tell on my little netbook screen
it relates to the blades... the side facing the wind...
are the blades mounted where the convexed side is facing the wind? or the concave/flat side facing the wind?
bob g
Thanx Bob. On the previous DIY PVC blades the concave side was facing the wind. On these commercial blades they are truly formed like an airplane wing and that which would be the convex shaped upper side of a airplane wing is pointed towards the oncoming wind.
That is some project. That thing is huge. Great work! I am at total amazement what you built there.
Henry
Thanx for the support Henry!
The control cabinet at the bottom of the tower operates on a 12 volt AGM 50 A/hr storage battery. The relays and contactors, as well as the azimuth motor brake release solenoid required 28 VDC to operate, so a 12 to 28 VDC upconverter was included in the design. Upon opening the control cabinet weather sealed door this maintenance panel becomes accessible. For example, one function I can access from this panel is to apply the brake and place AZ in manual mode. Here I can rotate the nacelle either CW or CCW in order to 'polish the brushes and slip rings'.
Due to health problems I have been unable to do much of anything this year on the nearly operational HAWT. The system exhibited destructive tower resonance and was really oscillating like a standing wave on a skipping rope. Left to run I'm sure this would have collapsed in short order, just like the 1940,Tacoma Narrows Bridge disaster. Google 'Galloping Gertie'.
I have had to tinker with the new hollow, fiberglass Chinese blades since rain water got into one through a bolt hole through the root and really unbalanced the assembly. I also had to re-machine the input shaft coupler to the first of the four pancake generators as it was causing a slight wobble (like a precessing gyro), of what is essentially a rotating flywheel and this wiggle was modulating the tower!
The good news is that I don't think I'll have trouble getting 3kW+ out of this package since it already easily made 2500 watts on a short test in 'not so big wind'.
This summer I managed to get most of the work done to add six more guy wires which will be at 120 degree points and place a much more favorable angle where they attach as close to the tower below the spinning blade as practical. I did pre-paint the two arms and support members before installation, however I do not possess a ladder long enough to get to the 21 foot long guy wire outrigger arms, so the support weld partway out is not finished nor painted yet on each of the two arms now in place. Lastly I have to add a 13 foot extension pipe to the 8 foot arm that is out to the right at the tower tilt point as seen in the attached picture. This will place one more guy like the other 120 degree ones and complete the guy package. I have done this in such a way as to avoid planting 120 degree spaced guy wire anchors 50 feet from the tower and reducing the practical enjoyment of my field.
No further work at all on the larger BGT, VAWT. I was held back by not having critical material needed for the blades which I finally scored last summer.
I must apologize that the videos I had linked to from some posts here are no longer available. I'll have to remove or replace the links. Those videos are not currently hosted.
I'll post again when there is more to tell.
rca
VERY nice work Rob!! 3kw is pretty significant.
BTW the "Night Crawlers" are new, PM me when you get the chance.
Ron.
Quote from: vdubnut62 on September 02, 2014, 12:20:41 PM
VERY nice work Rob!! 3kw is pretty significant.
BTW the "Night Crawlers" are new, PM me when you get the chance.
Ron.
Ron,
Pls check your email box.
rca