DIY Wind Turbine Using Car Alternator

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Introduction: DIY Wind Turbine Using Car Alternator

About: Being a science student i love to indulge in projects related to engineering as i love to learn things practically...

So its time to try our hands on building a wind generator using a truck alternator.

Yup we recently did came across a 24v alternator thats in brand new condition so we built a wind generator completely out of scratch. Our goal is to figure out if this idea is worth it or not, so its time to find out.

Step 1: Supplies

The list of tools and material used in this project are listed below:

MATERIAL USED:

  • 24V 60Amp Alternator
  • 20mm square metal bar
  • Metal tubing
  • Metal shaft
  • 8' metal plates (round)
  • 6mm metal plates
  • Wire
  • 6' PVC pipe
  • Nut,bolts & washer
  • Paint

TOOLS :

  • Welding plant
  • Grinder
  • Drill machine
  • Belt sander

etc.

Step 2: Alternator Mods

In order to make this alternator usefull for our wind turbie we have decided to do some modifications & alteration. For that there in an oil pump / peristaltic pump that we dont need anymore so we unscrewed that and now we are ready to remove the pully and the cooling fan behind that.

So we have got the alternator dissassembled and as you can see over here this commutator provides the power to the rotor in order to magnetize it and this connector that might seems like its connected to the rotor is not, because there is a voltage regulator in between that makes sure that regardless of the engine speed the alternator generates consistent voltage so we need to bypass the voltage regulator andd directly connect a pair of wires to the carbon brushes to magnetize the rotor coil using an external battery pack.

So we have sucessfully hacked this alternator and its producing 18v at arround 700 RPM besides that the rotor coil is drawing nearly 30 watts of power from a 3 cell lithium battery. Now its time to built the frame for our wind generator.

Step 3: Main Frame

Now time to get our hands dirty as we built the frame to hold everything together.To make the whole unit sturdy we have used 20mm metal bar for the main frame. Once we chopped all the parts we threaded the motor mounting that will later allow us to glue the parts before welding them together.There are three mounting holes on the alternator, two of them are inline while the thrid one is on the opposite end. So we built the frame arround the alternator. We started with the inline holes and then added pieces to get to the third one. Once all these pieces are welded we than trimmed the excess length of the metal bar using a hole saw. This will help us to attach the frame to the bearing holder that will allow the turbine to follow the air direction. Then we have welded the 2' metal pipe which act asa bearing holder for our frame and we have welded some additional metal bar to give its some extra rigidity.

Step 4: Furling Tail Mechanism

The frame is built arround the alternator followed by a bearing holder that will allow to point the generator into the wind direction. Now instead of going with the fixed tail design we decided to built a furling tail that will prevent the generator from overspeeding. For that we have used a metal bush which we extracted from old hoverboard and some metal pieces. After doing some research on internet we have find out the best position for furling tail mechanism is we have to mount our tail holding bush in 20 degree tilt angle. So we have welded 6mm piece with bush in order to maintain distance between bearing holder and tail.

For the tail bar we have used 14 gauge 1*2 inch metal tubing 40 inch length welded with 25mm metal shaft with the 20 degree angle. And the drilled some hole on the other hand to attached the acrylic sheet.

Step 5: Front Plate & Blade Holder

After completing the tail mechanism now its time to make the front plate assembly which will later going to attach to our alternator rotor in order to rotate it. So for that we have used 5mm thick round metal plate which will enough for are five and three blade design. Then we drilled the holes and threaded M6 in order to avoid using the extra nuts.

For clapping our blades to the front plate we have used the 6mm thick metal strip in order to get the rigid base for our PVC blades. And again we have drilled and tapped M6 threads to clap our blades.

Step 6: Paint Job

After finishing all the parts now its time to get the paint job done, for that we first clean and degreases all the parts and then painted with matt black auto paint. The whole paint job proces was very satisfying and the results were pretty decent.

Step 7: Making PVC Blades

Once we set the parts to dry it was time to start working on the blades. To keep things simple we used PVC pipe thats 6 inchs in diameter and 44 inches in length. We started by chopping the pipe into three pieces each of which was later sliced into a pair of blades. And then rounded up the edges and drilled the holes according to our mounting plates.

Step 8: Final Assembly

First we have added the ball bearing in the main frame cylinder and slide it on the main shaft which is soon going to be attached to our main post on top of our roof. And then attached the alternator to the frame by using M10 screws and then placed the front plate and tightened up by using impact wrench. Then palaced the metal strips in order to mount our PVC blades together. After that we slides our tail rod and attached a piece of 6mm thick acrylic sheet in order to make our wind turbine to follow the wind direction.

Step 9: Mounting the Turbine & Gathering Results

Now its time to take our wind turbine on the roof our workspace and then we have fastened the turbine unit with the plate of our post and done some wiring work by attaching the rotor coil to energize our electromagnet and also made the connetion for our main output possitive terminal and the whole body as negative terminal.The wind was blowing quiet alot and if you have noticed the tail started furling towards left, this happens when the blades achieve momentum as turbine reach its threshold speed, which can be lowered by decreasing the size of tail and its weight and vice versa. This prevents the turbine from overspeeding as the blades are not following the wind direction anymore.

Aside from having this much wind we are unable to get the required RPM. We were aiming for 700 RPM while the turbine initially achieved 200 so we switched to shorter blades which did increased the RPM but still we are half way down there at 350 RPM. The maxiumum output we were able to get was arround 50 watts which barely compensates the amount of power we are using to magnetize the rotor coil and is way less than what we have expected.

Using a car alternator for a wind turbine might not be a good idea but there are some tweeks that we are looking forward to overcome these issues like replacing the current rotor with a permanent magnet one and increasing the rotor speed using a higher gear ratio between the blades and the alternator. Now thats something we will cover in another video, so drop down your suggestions in the comments section below.

Now thats our take having fun with the winds and building this wind turbine, hit thumbs up if you loved the built and we will see you soon in the next one

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    26 Comments

    0
    bpark1000
    bpark1000

    Tip 10 months ago on Step 9

    Your statement "Using a car alternator for a wind turbine might not be a good idea" except replace "might" with "IS". Car alternators are designed to be CHEAP. In their intended use, they are lucky to be 50% efficient (who cares? There is a 100HP engine behind it. What do you think that fan is for?) The steel laminations in the stator are way too thick causing high eddy-current losses. What some have done is to replace the rotor electromagnet with rare-earth magnets. This gets rid of the rotor power loss, but because of the thick laminations in the stator, the losses there are high. You also have to position the magnets carefully to minimize "cogging torque" which can prevent the turbine from starting up.
    There is something else that is not right (that may be the more serious problem why you are not getting more power). You reduced the length of the blades, & the speed went up! That shouldn't happen. There is something wrong with the pitch/shape of the blades. THEY MAY BE BENDING. A commercial turbine, blades a little shorter than yours, (made with alternator similar to car alternator except better laminations & permanent magnet rotor) gets 500W maximum in 30MPH steady wind.
    One thing you should try is changing the pitch of the blades (rotate them about the rod you have fastening them to the center). Ideally, the pitch should be set so the blade's speed through the air is 7 times the wind speed. The blades should twist along their length (you can heat the pipe & twist it, or cut it into sections & have each set at a little different angle. Other option is to have NO BLADE near the hub.)
    Another thing you need is a "maximum power point tracking" system. The load on the alternator needs constant adjusting as wind speed changes. (For example, if wind speed doubles, turbine speed needs to approximately double (which will double output voltage). If the load is resistive, the current would double, quadrupling the power to the resistor. But the power available from the wind goes up by 8 under those conditions, so the current needs to quadruple. If you connect (rectified) alternator directly to a battery, the turbine will be held back at high wind & run too fast at low wind. You need DC/DC converter between the alternator & the DC bus you are feeding. (This can be simple in the hardware, because the inductance of the alternator windings can form the "hard part" of the converter, requiring only a FET and a diode). For high-wind protection, the same FET that does the DC/DC conversion can short-circuit the output of the alternator. This causes the turbine to "stall" & turn slowly. You could also build a voltage regulator to adjust the rotor current instead of the DC/DC converter (if you use the original rotor electromagnet). You then need circuit to sense when the wind is not enough to provide rotor current in this case & prevent discharge of the battery.
    You might have better luck with a hoverboard wheel motor for the alternator.

    0
    static
    static

    Reply 6 months ago

    Yes porkomy is correct, you have things backwards, go back and put the a;alternator in it's stock condition. Put two 12 V. in series so the alternator can function in the matter it was signed to to work. vehicle alternators are a poor choice for wind turbine. On reason,is ther need to be means to energize the stator, if there's enough wind is wind and de-energise the stator, when the wind stops to avoid depleting the battery bank. A PM rotor coul help in that matter. But reports are, they are prone to cogging*, an locking in place to a point it takes a strong wind to get the rotor spinning Most vehicle alternators, aren't physically robust enough for turbine service. In the event having a wind turbine ia critical for anyone, I suggest https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwiJuOig2ub0AhW2kIkEHRd1DAEQFnoECAQQAQ&url=https%3A%2F%2Fwww.engineeringforchange.org%2Fsolutions%2Fproduct%2Fpiggott-axial-flux-alternator-wind-turbine%2F&usg=AOvVaw00qktDUGSyl851HNOxMsZJ

    0
    static
    static

    Reply 6 months ago

    Respectfully; this is far from the Hugh Pigggott design. The Pigott design use an axial flux alternator. .The only off the shelf alter google showed me costs over $4,000, so a Piggott alternator most likely will be home shop built. The Piggott design. is probably the most robust home shop build wind turbine out there

    0
    fCauneau
    fCauneau

    8 months ago

    OK, in fact as your design and project is a clone of the Pigott WT concept, you should have gone to Pigott's builders websites and forums first. This should have avoided many troubles to you.
    And when you say : "We were aiming for 700 RPM while the turbine initially achieved 200 so
    we switched to shorter blades which did increased the RPM but still we
    are half way down there at 350 RPM"
    No : If you shorten the blades, you just decrease the power. Go back to your first blades, and keep only three of them. This will almost double the RPM, ad if you keep only one blade, you'll almost 7X your 200 RPM (and still the same power). So remind it : keeping constant the rotor size keeps the power, and changing the number of blades changes the rotation speed.
    Notice : if you try a one blade rotor, you must put a well-balanced short counterweight on the opposite side to balance your rotor (or you'll destroy it).
    You may try also a two-blades rotor, this will be closer to the 700 RPM you wish. But such rotors are subject to blade bending when functionning, and you risk the destruction due to schocks on the mast.

    0
    wdsparrow
    wdsparrow

    9 months ago

    Thank you! That was so much fun watching you build it. You answered my question I had about using a non permanent magnet alternator (providing power to the winding). It's unfortunately your result did conclude with no tangible benefit, but I learned lot. Thank you so much.

    0
    stackerjack
    stackerjack

    9 months ago on Step 9

    I think the blades are all wrong. Much better if you were to cut the blades at an angle to the axis of the pipe. Look up "Making A Propeller for a model Plane"

    0
    shalnachywyt
    shalnachywyt

    10 months ago on Introduction

    Intriguing. I have an old groundhog and other ground pest-type "windmill" that I was going to use as an "art" project, but after seeing this I was wondering if I couldn't adapt your project using that "windmill" instead. Do the length of the blades have to be a certain length? The blades on the "windmill" I have are 18 inches (45.72 cm) total long.
    I think the only trick would be getting some type of smaller (?) alternator to use. Got any suggestions?

    0
    bpark1000
    bpark1000

    Reply 10 months ago

    Most of the "groundhog" & farmer's water-pumping windmills are focused on high torque & low speed. They have many blades, set at steep angle to the wind. They are not good for extracting power from the wind.
    With 18" blade, set at low angle to wind, you should be able to get 300 to 400W from the wind at 30MPH with proper alternator & tracking circuit. The blade's angle is correct when the blade's tip speed is 7 times the wind speed.
    You could try some of the larger "outrunner" airplane motors (smaller turbine), or hoverboard motors (larger, slower-turning turbine).

    0
    Incognatio
    Incognatio

    10 months ago on Step 1

    In a past working life, mid 1980s,I re-purposed automotive alternators for Pelton turbines. A company then called Tamar Designs in Tasmania manufactured a bronze Pelton turbine for remote power applications. Key criterion was that it had to be uncomplicated and inexpensive to maintain. The era was pretty much before that of readily available of permanent magnet units. In a nutshell, we repurposed both the 24 V and 12 V Bosch pattern automotive alternator designs by simply fitting a rotary rheostat between the inbuilt brush box regulator and the slip-rings. To the attached control panel we added an ammeter on the output supply. Functional control was simple. With the Pelton wheel up to speed at full resistance on the rheostat and output amps at nil, increase excitation voltage with the rheostat watching the ammeter increase. At the point where the output maximised, the maximum available kinetic energy from the Pelton wheel for that particular penstock had been extracted. For such a simple re-purpose, the outcome was as good it is could be for a regulated excited alternator. Of course service was simple, anywhere even in Papua New Guinea, Timor, Pacific region and off grid Australia. With the advent of low cost readily available permanent magnet motors/generators, excitation losses reduced and system % increased. Now the design, although redundant commercially, is but a cinch to build in the back shed. Face book contact at nulla incognatio for tech details-- if I still can find them.

    0
    bpark1000
    bpark1000

    Reply 10 months ago

    The problem with wind is that it is not as consistent as water. You would need a "little man" constantly tweaking that rheostat. That's why commercial turbines have "maximum power point tracking" circuits. Modern electronics makes this simpler.

    0
    pokorny
    pokorny

    10 months ago

    If my memory serves me correctly you should be engrizeing the stator not tge armature. The reason being is the regulator engerzige the ststor of the firld to generate and the aramture then spins through the magnetic feild cresting power

    0
    bpark1000
    bpark1000

    Reply 10 months ago

    They are energizing the correct part (the rotor).

    0
    ziqfriq.
    ziqfriq.

    10 months ago

    The weak link seems to be your turbine. It's great you were able to construct one out of cheap and widely available PVC pipe, but more time spent on the design of the blades and perhaps having them fabricated or buying some off the shelf blades might really pay off. I know the idea was to use cheap or scrap parts, but 14KW of free energy might pay for itself soon!

    0
    doctormarkglickman
    doctormarkglickman

    Tip 10 months ago

    They could have attached the propeller blades with metal wire. It would be cheaper and more reliable. Nuts and bolts and become loose. Alternatively they can also rust and it can become impossible to remove them if they rust.

    0
    PeterH293
    PeterH293

    10 months ago

    With blades that long your turbine should be whizzing round.l think your problem is in the design of the blades, which need a high angle of attack at the root and a smaller angle of attack at the tip. Your tip angles look to be almost flat.

    0
    ron342
    ron342

    Reply 10 months ago

    Blade design might be the problem, hard to tell from the pics how this is configured but a lot of science (and experimentation) goes into the blades!

    0
    Atilla De Hunn
    Atilla De Hunn

    10 months ago

    I built a wind turbine using a car alternator wired up the same way it is in the vehicle for powering the magnetic field. Old car generators are very hard to find now days as most were sent to scrapyards many years ago. For the turbine blades, I used two oil drums split in half and each half mounted horizontal, in reverse of the other to catch the wind and provide a larger Torque Arm for low wind speeds. One set mounted above the lower set at 90 degrees offset. It was mounted on a turntable with a bearing underneath, and a central pone with guy-stays from the top of the pole pegged into the ground. It produced enough juice to power the lights and appliances in a remote cabin. All lights and appliances came from a junked RV whish was designed for 12 volt DC operation. All batteries were wired in parallel to provide a large source for operation (salvaged car batteries). The rig was mounted on an old Windmill platform.

    0
    rossnmare1
    rossnmare1

    10 months ago

    Washing machine (Fisher & Paykel) electric motors have been used for home generators.