Winding a three phase axial flux stator the Mike's Windmill Shop way
WE ARE DESIGNING NEW INSTRUCTIONS DUE TO THE MAGNETS THAT WE HAVE BEEN USING NO LONGER BEING AVAILABLE. WE ARE LEAVING THESE UP FOR A COUPLE OF MONTHS FOR ANY OF YOU WHO ALREADY HAVE YOUR SUPPLIES THAT ARE WORKING ON THIS PROJECT
THE NEW INSTRUCTIONS WITH A DIFFERENT SIZE MAGNET WILL BE AVAILABLE HERE ON OUR WEBSITE BY THE END OF THE YEAR. ARE IN THE PROCESS OF WRITING THE NEW INSTRUCTIONS
The first step in building your powerful axial flux wind generator will be to wind a stator. Here we teach you how to wind with three phase windings. We use a wooden disk behind the windings. This makes it so that the stator plate does not have any metal behind the windings. This allows the wind generator to spin very easy and to get started in low winds. The wind does not have to fight against the pull of magnets against metal because we do not use any metal behind the copper windings. By following the method that I am going to teach you, you can build a very efficient wind generator.
Wind your own powerful wind generator the Mike's Windmill Shop way. These windings are best used with our 7'3" diameter windmill blades. You can build a fixed frame system for areas with lower wind speeds. If you are in an area that get high winds, over 50MPH, you can build one of our high wind tilt outs. This size wind generator produces great power. Your goal in winding this wind generator for a 12 volt system should be to get 3amps in 10 MPH winds. When I wind this stator in our shop I am getting 11amps at around 20MPH winds. In higher winds I have easily seen 56 amps. In extreme winds I have even seen 60-70 amps. With some practice with these windings you should be able to get the same power.
I have designed an easy to use stator plate. This allows you to easily wind your own axial flux wind generator. You can build your own winding plate or you can purchase one from Mike's Windmill Shop, LLC. The winding plate that you can purchase from us has the larger wood disk, nine smaller wood disks, stainless steel bolts in each of the nine disks along with the stainless steel nuts. It is ready for you to begin winding.
Building the Winding Plate
To begin you will need a 16-1/2" diameter plywood disk. Use 5/8" plywood. You will need a good flat piece. You do not want to end up with a warped stator. You will also need nine smaller disks made out of 5mm Lauan plywood . The smaller disks need to be 2-7/8" diameter each. You will need to evening space the disks so that they will line up correctly with the magnets that you will be using on the magnet plate. The easiest way is to mark the spots where the magnets will line up and then drill the bolt holes for the disks. They will need to line up to the magnets on the magnet plate. We will explain how to build the magnet plate and how to line up the stator to the magnets in our next lesson. You can always purchase a stator plate from us that is ready for you to wind. You will also need nine stainless steel bolts and thirty-six stainless steel nuts. Grind down the head of these bolts so that they are flat. This way you can get the magnets closer to the stator coils so that it will produce more power. In the photo below you can see that bolt A has a rounded head. This is the way that bolts are originally made. You can see how Mike has ground down the head on bolt B to make it flat. When grinding down the head of the bolt be sure to use leather safety gloves, goggles and use pliers to hold the bolts so that you hands are not near the grinder. You must use stainless steel nuts and bolts in the stator winding plate. If you use regular steel bolts they will cause a pull on the magnets and the magnet plate will not turn as easily.
Thread the stainless steel bolt through the smaller disk. On the bottom side of this smaller disk thread three of the nuts on to the bolt. You will use three stainless steel nuts. These nuts will create a spacer that will give the correct space between the smaller disk and the large disk that forms the stator winding plate. Tighten them and the cover them with electrical tape to protect the copper magnet wire that you will be using in the stator. You will be winding the wire around the bolts that are under the smaller disks. After you have all nine disks ready you will then fasten them to the large plywood disk. Place one smaller disk in each of the holes with the disk facing to the front. On the back place one flat washer and then tighten with one stainless steel nut. The stator plate is now ready to wind.
Winding the copper magnet wire
You will wind the wire in a counter-clockwise direction. Make sure that you wind each phase in the same direction. If you wind any of the coils in a different direction than the rest of them it will rob your wind generator of power. If you mark the disks as you see in the photo above it will make it easier to remember which coil you are on and which coil to wind next. You will begin with 1A. You will wrap the magnet wire in a counter-clockwise direction. Try to wrap the wire tight so that there will be enough space for all of the wrappings. We will tell you in the list below what size wire and how many windings you will need. After you have finished the windings for 1A you will continue on to 1B and then on to 1C.
After you have finished 1C you can cut the wire. Make sure that you leave several inches of wire at both ends. Now you will repeat the process for the second phase of the windings, starting with 2A, moving on to 2B and then 2C.
Repeat the same for the third phase with 3A, 3B and 3C.
For a 12 volt stator use 13AWG (gauge) copper magnet wire and wrap each coil with 87 wraps.
For a 24 volt stator use 16AWG copper magnet wire and wrap each coil with 174 wraps.
For a 48 volt stator use 19AWG copper magnet wire and wrap each coil with 348 wraps.
Make sure that you only use copper magnet wire that has a coating that is rated at 200* Celsius. This wire is usually amber colored. When the winds are high the wind generator will be producing large amounts of power. As the amperage being produced increases the wire will increase in heat. The higher amperage, the higher the heat created. If you use wire that is not rated at 200* Celsius the coating on the wire can melt off with the high heat and cause the wire within the coil to ground out against itself. This causes a burned out stator and you will have to wind another one. To prevent this you simply need to be sure that you are using copper magnet wire with a high heat rating.
After you have finished winding all three phases of the stator you will need to finish the ends of the wire. Clip the ends so that they will be even.
Next you will need to clean off the coating from the ends. To do this you will use a torch to burn the coating off of approximately 1 to 2 inches of the end of the wires. Then use sandpaper to clean the ends of the wire. Use a volt meter to test the wires. Use the lowest ohms setting. Many meters will beep to show that there is a connection. You can use this beeper setting but it is not as accurate as reading the numbers. Test the stator by checking wires 1A to 1C. Then check 2A to 2C. Last check wires 3A to 3C. Mike likes to check each phase as he finishes winding it because it is easier to correct any mistakes if he finds them early in the process.
Next you will twist the ends of the wire 1C, 2C and 3C together to create a connection. Then secure the connection to an aluminum lug. Use stainless steel bolts when connecting these lugs to the stator plate. Test the wires again. Put on lead on the number 1A wire and one on the number 2A wire. The meter should beep or show a low reading. This reading should be approximately double of what you saw when testing a single phase. This is because you are now testing two of the phases together. Now test wires number 2A and number 3A. Then test number 1A and number 3A. The numbers may not be exactly the same in each test but they should be similar. If you get a number that is too low or too high or does not read at all then there is a break in a wire or a bad connection. Usually it is just a bad connection.
Last, you will use aluminum lugs such as we show in the photo here to secure the wires. You will use one for the three ends that have all been connected together. These are wires 1C, 2C and 3C. You will use three more lugs with one wire going to each at the beginning of the wires. These will be wires 1A in one lug, 2A in a second lug and 3A in the third lug. These three connections are where you will run the wires from the wind generator, down through the tower pole and to the bridge rectifier and the run a wire from the rectifier to the batteries.
Protecting the Stator
After you have tested all phases on the stator and you have the connections finished you will need to put a protective coating on the stator. Use fiberglass resin to protect the stator from the elements. I brush on two coats of the resin. It is much easier to brush on the coating with this stator plate than it is to try to create a mold and pour a full casting over individual coils. In the photo below I am demonstrating this technique on one of our other types of stators. When applying the resin make sure that you do not cover the connections that will be needed later in connecting to the wire going down the tower pole. We also apply a protective coating of paint over the resin. Make sure that you use a high temperature paint. Your stator is now ready to use with the magnet plate to create a power wind generator that you can proudly tell your friends and neighbors that you built yourself.
Axial Flux-Lesson #2 --- Building the Magnet Plate Assembly
Axial Flux-Lesson #3 --- How to build a mounting frame for an axial flux wind generator using heavy duty bearings
Axial Flux Lesson #4 --- How to build a set of aluminum blades
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