The following project is a little bit different when compared to the usual things I post about. Although there isn’t really any fabrication details I am going to talk about it still constitutes as a worthy blog entry and involves the garage and building cool stuff.
At the beginning of the school year I had talked with my daughter’s grade 5/6 teacher and offered to help out with any projects that he may find I was skilled enough to deal with. He had been teaching a renewable resource and a “Mission to Mars” unit lately and wanted to have the students build an electrical generator. He approached me with a set of plans that outlined how to build wind turbines that would power an LED light. After looking through the information I agreed to help out but it would have to be done gordsgarage style.
The plans he gave me, which outlined the build steps, were good in theory but lacked some serious user friendly build techniques. Lots of glue, time, and balancing techniques were used to come up with a turbine that might work but would take a week to complete. I decided to introduce the “lean thinking” philosophy and cut out everything that wasn’t required, streamline the build process, make sure that failure was not an option, that 28 could be built in less then 1 school day, and redesign the project so that the turbines would result in proud students.
As much as I would like to share the original, supplied, design the information is irrelevant. My design involved using cheap, some donated, materials that would provide a well balanced and rigid wind turbine. Using DVDs, recycled plastic tubes, MDF (medium density fiberboard aka wood), dowels, and wood screws made sure the project would come in on budget. In order to ensure the success of the project jigs were built to help the students “measure” and line things up as they fabricated.
The basic concept of the wind turbine is as follows. The turbine has 4 neodymium one inch magnets glued to the bottom of the lower turbine DVD. The MDF base has 4 coils wound from magnet wire that sit just below the magnets. As the turbine spins the magnets pass over the coils of wire thereby inducing a voltage.
So before I get you on board with what I all did I am going to start with the end. In the end the project was a success. Students each created a functioning wind turbine making 28 turbines in total in less then 5 hours. Although some of the turbines required some tweaking in the end to get there “spin”on they all generated a voltage and lit up an LED. I have posted a “how to” video towards the end of this post. I initially created this video as an instructional aid for the adult volunteers that helped with the success of the project. The video is just over 14 minutes long and I am not expecting people to dedicate that kind of time to watching it but it does clear up how all the jigs work and the entire process involved in the build. If you’re a hard core blog reader start by watching this video. On with the show!
So here it is in all its glory. The wind turbine! Get Mother Nature cranking on this thing and it’s sure to move some electrons. Built from DVDs, plastic tubes, and wood it’s ow budget electricity.
These are the guts of the system, 4 coils of magnet wire and 4 neodymium magnets get the juices flowing. The center wood screw that the turbine spins on allows for fine tuning of the air gap between the magnets and coils.
The following video gives you an basic idea on how the turbine functions using compressed air to spin it up.
For those of you interested in the nitty gritty details here is the scope pattern I pulled off a turbine during testing phase (ha! I said phase)
That’s right boy and girls, 1.620 volts! I actually got almost 2 volts out of it with a bit more spin. I never measured the amperage however it would be just enough to light up the LED.
So on with the stuff I built in my garage. Much of my time was spent fabricating jigs. Pictured here are is mostly fabbed hardware that makes up the magnet wire coil winding machine.
This is the flywheel for the coil winding machine. It was built from MDF wood to give it some weight to help the spin. It was built to provide an 8:1 wind ratio.The students are required turn the flywheel 25 times for each coil which results in a 200 winding coil. Multiple this by 4 coils per project and 28 projects this wheel was spun 2800 times in 1 day of building which resulted in over 22000 windings.
This is the completed coil winding machine. The bulk magnet wire roll slides onto the lower right aluminum peg and the wire gets wound onto a bobbin.
This is the bobbin which the 200 wound coil ends up on. I built is for quick disassembly and reload. If you want the see this machine in action you’re going to have to watch the dreaded 14 minute video near the end of this post.
The next few photos involve making sure students would have success at using power tools. The MDF base and upper turbine support needed holes. Letting students loose with cordless drills didn’t seem like a great idea so I built this jig to clamp the wood in. The hole spacing, and depth, were all marked out so perfect, consistent, base prep would take place.
Here the jig is opened up and the wood, and upper square dowel, are clamped in place. Again, if you want to see this in action then watch the video.
In order to ensure the right size holes are drilled everything was color coded. Depth stops were also fabbed for some of the drills.
Magnet safety was a big concern for me. I could picture the chaos that would occur if you let 28 students loose with 112 neodymium 1″ magnets. These things will pinch, and break skin, if they snap together. Since all the magnets would need to be handled I built a holder that was parent supervised. Each student could determine correct polarity of the 4 required magnets and then place them in the safety holder while gluing on 1 magnet at a time. This picture shows the internal guts of the holder.
This is the assembled holder where 1 magnet gets loaded at a time. The center MDF ring then gets rotated to the next detent so the magnet is held for safe keeping.
This jig is used for gluing magnets and washers onto the upper and lower DVDs. The lower DVD is sandwiched between the red base and upper aluminum spacer. Items can then be hot glued in place to ensure perfect alignment. The red base then gets flipped to provide a different jig for the upper DVD.
My original turbine blades consisted of 3″ cardboard tubes however I eventually got onto plastic ones. These are the inside tubes of 3M automotive paint protection film rolls. I have friends that apply this stuff so they were kind enough to collect the left over tubes for me. The plastic made way better blades. They were light, clean, and easy to hot glue.
The long plastic tubes needed to get cut to length and then split down the long way to make 2 halves. I built a wooden jig to aid in cutting the tubes on the radial arm saw.
This is the jig used to hold the turbine blades in place while gluing on the upper and lower DVDs. Again…watch the video!
If you’re gonna do it then do it right. I decided to use my vinyl plotter to create some station signage.
Magnet safety again. Once the magnets get glued onto the DVD base I felt as though kids would be holding a loaded gun. The solution was having each student keep their project in a plastic shoe box during the entire build.
All supplies were cut to length, counted out, and organized for each build station.
I had timed myself to see how long it would take to wind a coil. After the calculations were made it would appear that there would not be enough time in the day for each student to wind 4 coils. I opted to pre-wind some coils in order to ensure the project could be completed within a day.
The day of the build finally arrived. The fabrication shop was set up in the school gym. Stations were created, and run by parent volunteers, for each step of the build process. Here students stated by prepping and drilling the MDF base.
Station 2 consisted of gluing the magnets and alignment washers onto the DVD.
Station three consisted of joining the prepped DVDs to the plastic turbine blades.
Station four turned out to be the magnet wire coil winding bench.
And station five was where everything came together in the end.
This brings us to the dreaded 14 minute “how to” video. If your interested in seeing how all the components fit together to create a functioning wind turbine it is highly suggested you watch the video. It’s actually not that bad, I’ve got some catchy music and I tried to keep things flowing to prevent boredom.