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Forum Index : Windmills : PhillM " AX 300 -1" Next Step
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fillm Guru  Joined: 10/02/2007 Location: AustraliaPosts: 730 |
Hi all, I have been a bit quiet of late due to the a couple of projects, I was full steam on my new designs for what I call the AX300 and Ax400 when the Chinese 500W mill came along , and then comming up with a lot of mods to get that performing better. I was back on track and off course mother nature had to step in and have her say , below are a couple of pictures of the stator out of the AX300-1 that show a very quick build up of heat which expanded the copper coils and cracked the stator and caused the magnets to start rubbing. 
From previous experience with posting pictures of failures here it usually opens up a can of worms with all the failure annalys debate , and I am sure this will be no different, but in a nut shell it was an extremly quick failure as I had the mill down 30min prior to the shut down to change the blade offset to allow a lower furl set point , there was no signs of heat or burning then as it was fairly pushing out some big numbers which can be seen on the last hour of data on the " Piclog live Data " HERE I threw the short switch as I was going to take my son to a soccer game and did not want to leave the system running with my wife home alone with it , and at the same time the wind was getting stronger, the blades did not go into stall and overpowered the generator causing the instantious heating . It goes to show that these designs are not infailable, I am also in the opinion that the Aluminium GE222 blades that I run also come into play with the massive power and inertia that they develop , but it all comes down to if you can not convert the power in the wind through the blades then you wont get the power out , so I am pretty happy to have the problem of having to much power on hand in that department , so it then comes down to being able to controll the power in higher winds . This event has then led me into a completly new nacell design that has been going around in my head for a good 12mths as I have not been happy with my origional idea of only being able to adjust the blade off-set to change the furl moment . I have now come up with what I think will give me the best adjustment to furling , as I have been down the road of trying the caculations with the formulars that give you a very rough indication of what forces are required to overcome the the tail weight or to caculate tail weight and length, which in my opinion do not work as there are to many other variables in blade types , alternator RPMs , rotating mass , friction and the list can go on . So I now have a Nacell / Tail - That I can easily change the Gen Head between a Ax300 & Ax 400 - Has 100A slip Rings - Yaw Bearings that are fully sealed - The tail pivot is also on sealed bearings - The tail pivot furl angles are fully adjustable on a X Y axis - The tail stop is Spring over Hydraulic dampened Below are pictures of my new Nacell and Tail design I have almost completed along with the new stator which should be up and flying in the next couple of weeks . 
There are a few other changes I incorperated into the stator build that will allow for better cooling of the coils if they do start to get some heat and need to expand along with a better air flow . The Spring over Hydraulic tail stop damper allows the tail go to a maxium tail off-set in light wind which should allow the blades to be slightly overcentre of the blade off-set force and then become square and balance the wind in 3 to 5 m/s untill the blade offset force then then takes over and startes to furl , the damper will the stop the sudden shocks from wind speed and direction changes . The tail pivot is mounted on two adjustable rod ends which allow the side and back adjustment or on a X & Y axis , this hopfully will allow me to set up a very smooth furl as the blades turn out of the wind . Anyway all will be revealed soon when it is up and flying again which will hopfully be in the next few weeks , I am also upgrading all the wiring to my two towers as well as all the rectifiers, Cap /Dblrs and logging controls. PhillM ...Oz Wind Engineering..Wind Turbine Kits 500W - 5000W ~ F&P Dual Kits ~ GOE222Blades- Voltage Control Parts ------- Tower kits |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Phill It looks very good to me, I like the adjust ability and the hydraulic damper, it should save a lot of gyro strain on the head. All the best Bob Foolin Around |
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Great post Phill, very nice looking machine. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Bad luck with the stator burn up Phil, but then again its taken you to a higher level in design. Nice work. Wish you good luck when the bird is in the air. Pete. Sometimes it just works |
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isaiah Guru Joined: 25/12/2009 Location: United StatesPosts: 303 |
Phill, I like the new tail design and have a question. How do you calculate the square feet of the vain with the angles on the front edge ? We have found here that a tail that is taller than the width seems to stay with the wind better. I try to put the horizontal centerline of the tail on or above the centerline of the generator.They seem to respond better in our low wind area. URL=http://www.motherearthnews.com/Renewable-Energy/1973-11- 01/The-Plowboy-Interview.aspx>The Plowboy Interview[/URL> |
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| fillm Guru Joined: 10/02/2007 Location: AustraliaPosts: 730 |
Hi Isaiah, I like the idea of a tall thin tail as far back as possible as well for better wind tracking , this tail is 2.4m in length . Caculating the surface area is just the formular of length x width = area , to work out the angle area, break it into two sections, first work out the rectangular area first then treat the triangular area the same as a rectangle and divide it by 2 or if they are the same then dont as that will be the total area of the top and bottom . 
Thanks- Glenn, Bob , Pete it is all a learning curve that we are all on and failures are apart of that , furling is something that is very hard to caculate so hopefully this will give me the ability to play around with the angles easily to finally get a furling system that works smoothly . PhillM ...Oz Wind Engineering..Wind Turbine Kits 500W - 5000W ~ F&P Dual Kits ~ GOE222Blades- Voltage Control Parts ------- Tower kits |
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| JimBo911 Senior Member  Joined: 26/03/2009 Location: United StatesPosts: 262 |
Phill Hey do you ever sleep, your always coming up with new mills and new designs? Nice work on your new nacell design. I know in time you will make this design work, looks very solid. I must agree tail furling takes more trial and error to get it correct and the Alum blades your selling can really crank out the torque. Having not built an AXFX I can't say I know that much about them so this may not make any sence. Seems keeping the stator cool is a problem with AXFX alternators. (IDEA) The stator not having any iron in it does not pull and magnetick attraction so it would seem that drilling lots of small holes lets say about 1/8 of an inch in dia or smaller in the stator casting would not weaken the stator casting integrity and may allow more efficient cooling, or possibly core a larger hole (round) in the center of the coils and insert some sort of Alum heat sink to help draw the heat away from the coils? Just a thought? Jim |
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| isaiah Guru Joined: 25/12/2009 Location: United StatesPosts: 303 |
Phill That Makes the figuring easy Thank You for the tip. Now all I have to do is remember it when I get to making another tail. Your outfit looks good to me.'  'URL=http://www.motherearthnews.com/Renewable-Energy/1973-11- 01/The-Plowboy-Interview.aspx>The Plowboy Interview[/URL> |
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GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
Hi Jim, It is not a good idea to place any conductive material in the centre of the coils on an AxFx stator. These will produce a lot of additional heat and drag. I have hollow coil centres on my own mill, and I think this is what Phill intends to do. I would be interested to know how much power is needed to spin an unloaded AxFx mill at say 500rpm. This could be a lathe test. I am looking at embedding some temp sensors in my own mill to record what goes on. Phill is building a mill that will be able to be configured to surely get the furling sorted. Gordon. become more energy aware |
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| JimBo911 Senior Member Joined: 26/03/2009 Location: United StatesPosts: 262 |
Gordon I am not sure how an Alum heat sink in the stator casting would PRODUCE more heat, would it not conduct heat away from the coils? How about placing some sort of Alum heat sink on the out side edge (Dia)of the stator such as a RING to pull some heat away, of course this may cause clearance problems with any housing cover. If having hollow coil centers for cooling works well enough then thats a good and simple way of keeping AXFX alternators up and running. AMEN I will have to go on your word of not placing a conductive material in the casting being I have NO experience with these types alternators. I do like your idea of gathering data on the operating temperatures. Jim |
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| Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Aluminum becomes magnetic inside an alternator and is what Gordon was talking about with additional heat and causing drag, it would be no better than an iron core if not worst. Think of the inside of an AC motor where the rotor is a aluminum block, this needs to become magnetic for the motor to work. Try waving some aluminum strap/plate over some strong magnets any you will feel the magnetic reaction. Pete. Sometimes it just works |
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| JimBo911 Senior Member Joined: 26/03/2009 Location: United StatesPosts: 262 |
Pete Ok I am sold, no metal, got enough heat anyways. Looking forward to seeing more of your AXFX (No lathe) build. Jim |
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| Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Hi Jimbo, Things are progressing slowly with the AXFX build, as too many other things to do also. Still in the process of making the molds for the fiberglass blades, although they have been pushed back a few weeks due to a family matter. Got most of the tower sorted (still in final construction) Then it will be back to the alternator. Sorry for the hijack phil............. Pete. Sometimes it just works |
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Tinker Guru Joined: 07/11/2007 Location: AustraliaPosts: 1904 |
Actually Pete, I think the "aluminium becomes magnetic" is not strictly correct but I know what you meant. What actually happens is that any conducting material moving through a magnetic field acts like a short circuit coil and currents are generated & start flowing within the conducting material. These currents create their own magnetic field which set up a force that opposes that of the magnet the material is moving through. This is why it may 'feel' like a magnet. This short circuit also causes local heating and would worsen, not improve, the stator coils it was supposed to cool as somebody suggested above. A message to any budding alternator constructor: please avoid any conducting material (other than the stator coils) from moving through or past the magnetic field of strong magnets. This would include nuts, bolts, washers, etc. P.S. Pete's example of the inside of an AC motor (assuming he meant a 'squirrel cage' rotor) did not spell out that the rotor is actually made of iron laminations but has cast in aluminium single turn coils where enameled wire once was on older style motors. It may look like its made all of aluminium but it would not work nearly as well if it were 
Suggest you take a rotor apart with a hacksaw for a closer look Pete Klaus |
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| Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
[quote]Suggest you take a rotor apart with a hacksaw for a closer look Pete [/quote] Been there and done that, i just could not be bothered with being too pedantic with my answer, and left that for you. The message got through just the same. I must be getting old and lazy rather than old and wiser. Pete. Sometimes it just works |
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