Introduction: Pinwheel Wind Generator
Pinwheel is a whimsical kinetic sculpture and a wind generator powering LED lights. The materials are mostly re-purposed and sourced from a surplus store in Kingston, NY as part of an ongoing conversation about renewable energy, resources, and waste. In 2016 it was part of the Helen Day Art Center's exhibition Exposed: http://www.helenday.com/exposed2016
Step 1: Build a Temporary Stand
While working on the pinwheel in a studio, it has to stand upright and be easily disassembled. Here I welded together four legs made from 1" steel square tubing to a small steel pipe at the top. The small pipe at the top is wide enough to slide in the center post and I drilled holes and threaded them with a 1/4-20 tap in order to use set screws to keep the center post steady. It's clamped to 2 x 4's for added stability.
Step 2: Source a Treadmill Motor (Permanent Magnet Motor)
The specs for the treadmill motor I used are: HP: 2.0, V.ARM: 130, A.ARM: 15, RPM: 3210
If you divide the volts by the RPM, the minimum ratio should be 0.035. The amperage should be at least 5. I used this website for the information: https://www.windynation.com/jzv/inf/making-wind-po...
Step 3: Make the Blades
I sourced the template from :https://www.thespruce.com/star-pinwheel-for-scrapb...
and I scaled it so that the blades had a total span approximately 4 feet wide. First I made one out of scrap card stock paper and cut it out to get the larger template to trace onto the aluminum. Depending how thick your aluminum is, you can either use tin shears or a band saw to cut it out of the sheets. The thicker aluminum I used for the final version took two people to bend it towards the center, so I would opt for something lighter like 16 gauge.
Step 4: Make the Hub and Attach the Nose
The blades attach to the hub on 5 equally spaced nodes around a circle fabricated and welded together from 1/8" thick mild steel. You'll notice a square welded on the back, it's not necessary, I just was trying to save time and material and cover a huge hole I mistakenly put in the center rather than starting over. Then I welded 1/2" steel rod to the face of the hub long enough to slide the nose on as well as accommodate the space for where the blades are bolted to the hub. The nose is an alarm system I found and gutted and then drilled a hole in the center. I threaded the top of the rod to secure the nose in place. Also on the hub are all the holes to attach the blades. Three for each of the 5 blades on the nodes and 5 around the center for the end of each blade to curve and bend toward the center.
On the back side of the hub, there is a pipe that fits snug over the shaft of the motor. To secure it onto the shaft, I drilled and tapped a hole and a nut (for more threads) for a set screw to keep the hub from sliding off. The shaft of the motor has also been grounded down with a mini grinder just a little bit so that screw can meet a flat surface on the round shaft.
Step 5: Attach Motor to a Bed
I threaded the holes at the bottom of the motor and used 1/4-36 bolts coming through from the underside of a bed made from 1/8" mild steel. There wasn't enough room for the wires so I raised the motor off the bed by welding two pieces of 1" square tubing to about 1" in length over the holes on the bed and used longer bolts and rested the motor on the square tubing rather than directly on the bed.
Step 6: Bearing
Since everything needs to be disassembled for transport and troubleshooting, the bearing on which everything spins horizontally like a weather vane is bolted to the underside of the bed. The bearing is attached to a separate small sheet of 1/8" thick steel with brackets and set screws (the set screws can't be too tight otherwise the bearing won't spin). The cast iron bearing is also welded at it's base to a 1-1/2" steel pipe about 14' long (pipes generally come in 10 foot lengths but I had to weld an extra few feet to adjust for the fact it needs to be inserted deep in the ground). The long pipe fit snug into the bearing I had found at a surplus store. Eventually the pipe will be inserted into a wider pipe for added stability minimizing deflection from the wind (the pinwheel was made to be installed in an outdoor sculpture park for four months in Vermont and it successfully withstood many thunderstorms!)
Step 7: Nacelle and Fin
The nacelle covers the motor and protects it from the elements, and the fin helps the blades move horizontally like a weather vane. I used 16 gauge steel on a slip roller and bending break to make the nacelle and polished it with a mini grinder. The fin is made from 1/2" rods and 16 gauge steel welded together. There are corresponding holes drilled to the nacelle, fin, and bed to bolt them together. You may have to re-polish the parts if a fire in a wood shop above your studio triggers the sprinklers and and rusts everything that hasn't been clear coated or painted.
Step 8: Electrical Components From the Motor to the Battery
The motor is connected to a 12 volt battery so in order for the battery not to turn on the motor and spin the blades, I soldered a diode to the wires of the motor where it connects to the wires that run down the center of the pipe. The diode keeps the energy running in one direction. (in the picture I took, the diode is covered in electrical tape). I ordered the diode here: https://www.windynation.com/jzv/search?sq=40+Amp+6...
I also used a slip ring and a charge controller. The slip ring allowed all wires to stop from twisting around each other. The slip ring I bought was sandwiched between the top of the bearing and the motor bed. I drilled a hole in the motor bed large enough for the wires to slide through. The hole in the motor bed lined up with the through hole of the bearing and pipes.
Slip ring: I bought a "Heavy 3 phase Wind Turbine Generator Slip Ring30 amp per conductor / Wire" from Ebay. The source of that is: http://www.slipring.com/miniature-slip-rings.html
The charge controller was necessary not to blow out the battery if too much power was coming from the wind. The charge controller didn't let the volts exceed 12. I bought "Wind Turbine & Solar charge controller 440 Amp 12 volt ADG type NO BASE U" from Ebay.
The order of electrical connections: motor - diode - slip ring - more wires to travel through the pipe - charge controller - battery. And then also connected to the battery were the grounds lights (next step).
Step 9: Battery Box
I'm planning to remove the battery all together so the lights can turn on only when the wind is blowing, but for now this is how it fits. I mentioned there is a 1-1/2" pipe that is inserted into a 2" pipe (to help with deflection) and there is a hole in the bottom of the smaller pipe for the wires to run through to the battery box. There is T-coupling toward the bottom of the 2" pipe for the battery box to attach to as well as the rest of the pipe that is inserted into the ground. I drilled the hole in back of the plastic box to attach a coupling and I drilled a hole at the bottom for the wires to continue to the ground lights.
Step 10: Ground Lights
I vacuum formed plastic over PVC pipes and glued 12 volt LED boat light strips to the inside. My friend found this amazing copper pipe and after cutting it on the horizontal band saw I slid the plastic pieces through them. It was a snug fit but I sealed where the plastic met the copper with a clear sealer anyway. I soldered the wires of the LED lights to extension cords that were then buried under ground and eventually came up through the battery box. I inserted PVC pipes and PVC elbows to the copper pipes to keep the light fixtures sturdy in the ground and protect some of the wire connections. The other ends of the extension cords were soldered to alligator clips that were attached to the battery.
Step 11: Install
With help, I dug a 4 foot hole wide enough to fit a 1" wide, 3 foot long Sonotube. First I inserted a 2" by 4' steel pipe threaded at the top where the cast iron T-coupling is screwed on (the T-coupling connects the rest of the pipe and the battery box). I inserted bolts on the sides of this shorter pipe to reinforce the cement around it. I filled the Sonotube with cement. Next came the longer pipes. The 1-1/2" pipe that is inside the 2" pipe is kept in place with set screws. There is another coupling at the top of the 2" pipe with a rubber ring inside to further minimize deflection filling any space between the pipes. The motor is too heavy so you have to screw it on after the pipes are standing upright. Then lift the blades to the top and slide it onto the shaft of the motor. It helps to have another person and two ladders. And don't forget a time capsule for the wet cement.
Step 12: Take Photos of Passersby