loading

The main objective of this project is teaching everyone the basic principles of dynamos, this way everyone will be able to build a generator that can be used to convert different kind of motions into energy. This time I’ll show the steps on how to build a simple and cheap wave energy converter (WEC).

Step 1: What You Need to Know

Based on the Faraday's law of induction we know that E=-N*dB/dt which "translated" into normal English says, the electromotive force is equal to the number of turns (of the wire) multiplied to the change of the magnetic field within time. So let’s imagine we have a long copper wire and we start spinning it so it looks like a compressed spring, and now let’s put a magnet that fits inside and start pulling it in and out. If we check the two ends of the wire with a multimeter we’ll see that it’s generating electrical current.

Step 2: Materials

For this prototype I used tubes of PVC :

  • 2 of 2’’
  • 2 of 5/8’’
  • 2 of 3 /4’’
  • 8 simple 90° elbow joints of 2''
  • 8 simple T joints of 2''
  • 8 plastic caster wheels
  • Copper wire
  • Neodymium magnets (Any magnet will work but it won’t generate as much)

Step 3: Cuts

This project aims to show the basics of wave power conversion si it won't generate that much current/voltage

For a first try the measures are this:

1) Cut the 2” tube into 7.4” segments be sure to leave a bit more so you can polish the edges for an easy assemble. You’ll need 16 segments.

2) Cut the 3/4” and the 5/8” into 9.5”segments (no need to polish this ones). You’ll need 8 of each.

3) Cut the 2” tube into 4 segments, each being 18”.

Step 4: Assembly

1) Use a candle to heat the 7.4” long tubes so they can fit into the T’s and elbows, just heat one side in each tube and make 2 squares with the T’s facing up

2) Join both squares using the 18” segments

3) Drill a hole in each elbow, and place the screws from the caster wheels, be sure to cut out the secure so it won’t bother the rotation.

4) In each of the 3/4” tubes make a small cut 1inch from an edge and heat it so you get a plain part which you will also drill for it to fit inside the wheels.

5) Place the wheels with the tubes on the screws you placed in the elbows

Step 5: The Generator

On the 3/4 tubes you will start spinning the wire, now the estimation for each try is the next:

(Please nothe that I used 7 neodymium magnets of 14*5mm in only one tube)

- For around 100 spins the AC value is about 120uA

- For around 200 spins the AC value is about 21mA

- For around 800 spins the AC value is about 0.2A

Now it's up to you to decide how many spins you will make into each of the 3/4" tubes be sure to connect the coils in series.

Step 6: The Buoy

For the buoy I used an 8” diameter expanded polystyrene ball which was “secured using wire to keep it firmly joined to the 5/8” tubes.

It hasn't still been tested in the sea, but to use it safely in there, use some electrical tape to isolate the coils. Then you can put some silicone to prevent it from losing its stickiness.

As I can see, the idea is to induce EMS from small and slow movement of the magnet through the coil. On the other hand you have a great force in action. So your problem is the small dB/dt component, and not the induced current trying to stop the motion of the cylinder - put the bigest and strongest magnet and make many many turns on the coil and it will still move. So optimal for you is as big, as strong, as many you can make. On the other hand, from mechanical point of view, the bigest movement is in the vertical direction - try to put coils verticaly, or turn your design on the edge so to have vertical coils
<p>I know about the vertical direction but the sea here isn't as violent as those in Atlantic Ocean, that's why I chose to make it like that so it'll work even when the sea current is low(horizontal axis)</p>
<p>What is the wattage of the device i wonder? You only noted the short-circuit-amperage but not the wattage...</p>
<p>Wattage would be V*I right? on one coil it was about 0.04W really low but increasing the turns and the area can greatly increase the value. The original design, the one done in 3D would use a Ball and socket joint so it could carry a tube with a bigger radius, hope this helped</p>
<p>Actually if you increase turns, you increase resistance and lower the current. In the end you will gain as many volts as lost amperes and your wattage will remain the same. However, in reality this relation is not exactly linear so probably there is an optimal setup (expressed in number of turns) for your design, but I wouldn't expect more than double increase in power.</p>
<p>Yes, there is an optimal setup, but I'm still looking forward to learn it this semester. But I'm still sure increasing the area on the rings will help? I'm currently on vacations and can't find my teacher so I basically did this to get some help from people :D</p>
<p>ok </p><p>working</p>
<p>Glad I could help :)</p>
<p>how can it work</p><p>were you can placed magnets</p>
<p>Magnets go inside the 5/8'' tubes, you can place some glue to make them stay at one point of the tube.</p>
<p>neat project, how long did it take you to construct this?</p>
<p>After searching for all the materials(took me about a week) a little less than 6 hours, if you have experience into cutting and heating tubes it will take way less</p>

About This Instructable

3,929views

60favorites

License:

More by rodrigo.castro.9887:Wave Power Generator 
Add instructable to: