high voltage axial flux

[fanman]

hello fellas,

fanman here,

im just trying to get this posting done and what a mess, all my pictures were taking in the wrong pixel size and i don't know how to make them smaller, so i went with some finished pictures instead i had to readjust my camera for these, anyway ive made a 120 volt axial flux machine the last couple of weeks its been an alful lot of fun for me.

i made the gen with 1/2" steel plates so there would be no flexing, i used24 magnets per plate. 18 coils of wire each with #14 wire one in hand 110 turns. as ive built this i tried to get all the information possible from the board and use it wisely, so my generater is kind of a mix of alot of things on this board

i didnt completly fill the magnet plates with resin because i thought that it would create a little bit of air flow around the coils, and my coil plate is a little thicker than most it is 5/8" thick, i made it that way for one to get the voltage i needed with the wire i had and for two,i will hopefully have a little better efficienties at higher wind speed, hopefully thet will eliminate some of the stall problems people seem to have

i made the fram from a 4" pipe mainframe and 3" offset fram it is guite tough and hardy, i guess i can say it is overbuilt a bit, but anybody in this type of hobby knows mother nature will always win. hopefully ive eliminated a week framwork, i also as you can see used 3/4" allthread in my hub, instead of 1/2" again for toughness,the hub itself is a 3500# rating so hopefully that is strong enuogh also,

i used all the angle info from hugh manuel on the tail furling part of this machine, the tail is about 72" long, i havent got the tail blade on yet i am working on that.i sure wish i could of used all my other pictures on this gen owell.

. i also am in the process of building blades for this machine. ive built a handy little jig that i can use to create the blade face, ive made several sets of blades with this jig and it works great, you just place the blank in it and make a plate for your router which rides along the top edges fo the box, if you notice the box has a straight edge on the back, which would be the leading edge of the blade, and the closer edge if you notice has the appropriat angles for the trailing edge of the blade



i just looked at the blade box picture and i guess you cant see the trailing edge sorry, anyway im making these blades out of 30 year old pine i got from a remodle job super dry and straight, i laminate it together with epoxy resin and that makes them super strong and water tight. well i hope to have this on a tower in a month or so and see what it will do. it will be a short test tower, i really need to fine tune this before it goes on my permanent tower, which is 158' tall and homemade,i really enjoy building my own things and creating my own power. i would really like to make a much larger machine like a 10kw, so anybody with some helpful ideas, lets talk. thanks all you guys for your input and for making this world a better place. if you notice in the last picture behind the tablesaw there is a whirlwind machine on the floor does anyone have anything good to say about that machine. the tag says its a 5500watt 120volt unit ive heard that there governing system sucked, but its never been put on a tower, i have the sitka blades and all that goes with it, i got it at a sale here in northern mich. what a find eh?

[Slingshot]

Fanman,

That router-guide box is a really cool alternative to marking and laying out lines on each individual blade.  Looks like you use a long extension shaft or something, or a very long router bit?

[Flux]

Nice machine.

Only comment is that your stator support system doesn't seem very torsionally stiff.

As long as you don't stop it by shorting it should be ok, but if you have to, I suspect there will be a lot of twisting force on the ears of your stator.

Keep us posted on progress.

Flux

[SmoggyTurnip]

Hey thanks for the pics.  It is a great looking machine and your jig is giving me some ideas for when it comes time to make my blades.

[fanman]

hey slingshot

yes the router bit is a 3"long 3/4"wide straight cutting bit and of course its carbide, 1/2" shank

[Cjohs]

hi fanman

looks like a great machine

did you say 158' high tower? - homemade? Any info on that?

what are the dimensions of your blades? looks like about 8m diameter (sorry I'm european) that would be about 25' ?

[fanman]

hey cjohs

 fanman here,yes i built a tower for my first jacobs wind machine back in 1997, it was a three legged, free standing tower with a 20' footprint the legs were made from 3" oil well casings, the kind they drill with. and about 95 20'sticks of 2x2x1/8" angle irons, i designed and built it on the ground, and hinged to of the legs to my anchors that were buried in the ground then i had a crane service com stand it for me with the jake machine on top, that was an awsome day, that crane just picked it up like it was nothing. and my blade box works real well, it only does the face of the blade but it does a great job, the blades in my pictures are only 8' long and they are 8" wide at the root and tapered from 5 degrees at the tip to 10 degrees at the root the blades are only 1 1/2" thick so the root isnt real deep, ive made several sets for jakes in the past, out of spruce, pine, redwood,cedar, and they all work fine, the pine tend to warp if not real dry.

[Experimental]

 Very nice fanman,

    And I love to see laminated blades, as they are much stronger and ridgid -- I do them a little different, but yours look great !!

   With a little modification,of your router box, you could do the back side as well, at any rate a flat rough out, then all that would be left is taper the back edge, and round the front !!

   Great job and keep those pictures comeing !!!   Bill H......

[richhagen]

Your metalwork looks nice.  I suspect it will be strong enough, with the half inch steel.  It looks like you used 1/4" bar stock for the stator mounting brackets, which is probably strong enough as it is what others have successfully used, but you beefed up most everything else with the stator and rotors.  Thanks for the post.  Rich Hagen.

[harrie]

Hey Fanman, looks good. I have just completed three 9 foot blades using the same method that you are with the router, except I used a skillsaw. I would have used a router too, but I didnt have a long enough bit. anyway, they turned out perfect. some are going for stright angles on there props now, but I perfer the twist and the jig works great for that. I normally keep the tips flat, and twist down from there to a 2 inch thick root. I think the flat tip, is the reason I get very little noise from them in motion.

Great fun, Harrie

[Frank06]

Without having any real-world experience with this at all, I still worry when I see things hanging out that far (stator) and was wondering how stiff it was?  I would say that if you can move it at all by hand that you should try to improve torsional stiffness perhaps by using large washers on each side of where the allthread bolts to the stator mounts?  Maybe you could gusset the allthread somehow?

Nice looking shop BTW and great looking project!

[theTinker]

that is a very fine looking machine, you must be very proud,

i hope u dont mind me feeling intense jealousy.

[SmoggyTurnip]

That tower sounds increadible - do you have any pics of it?

[John II]

Hello Fanman: What a fantastic looking axial flux machine !

Are you running a 120vdc system ? If you are.... I'd love to hear more about it. I'm trying to do the same and having some problems finding voltage regulators etc.

On the Whisper unit, I'm somewhat familiar with them. My father was a dealer for a while.

My experience with them, is that there was just enough slop in the bull wheel ( the big gear that is used for steering these machines out of the wind ) that as the small top fan tried to turn the props out of the wind... it would set up a severe vibration that would almost shake your tower to pieces. This problem increased with the size of the machine. Their smallest machine had such a high tip speed that the vibration was minimal. There 9kw machine was horrible. Another problem is when wind gust hit these machines the machine could not respond to it quickly enough and it put a lot of stress on the blades. That's the advantage of a tail.

One of two things I believe would totally solve this.

( 1 ) Go to a 3 blade prop... but you'd have to go to a slightly higher tsr or your voltage would drop because your RPM's would be slower then the original two blade.

( 2 ) Go to the cantilevered tail method. ( still a 3 bladed prop should no doubt be used )

Please let me know more about your 120vdc system ( If you are running at that voltage ) I need all the info I can get on setting my system up here in S.W. Missouri : )

John II

[BigBreaker]

I'm curious why everyone uses radially oriented stator brackets?  It would be better to have them project from an offset point form the axle and at a significant angle versus radial.  That would swap a lot of the torsional stress for compression or tension in the steel which is MUCH stronger.  The configuration that most people use creates a huge lever arm that transmits a lot of torque through a weld point!  Never a good idea...

Spoked tires use the same configuration that I am suggesting.  A bicycle's wheels use spokes that attach to a circular offset on the axle side and project from that offset to the tire in a non-radial direction.  Said another way, if you follow the path of the spokes past their attachment point you don't hit the axle or pivot point.  This allows a thin member which is totally incapable of transmitting torque to operate in tension to accomplish the same task.

Now imagine if the bracket spokes on our turbines were single bolted to the frame and made a few inches "too long".  Then each one is rotated in the smae direction so that they form a smaller radius circle than if pointed radially.  This smaller circle lines up with the bolt holes for our stator casting.  With the offset spokes bolted to the stator casting you have NO torsional stress.  It only uses compression and tension.  The stator casting also needs to be strong in those modes but that is much easier to reenforce and you have avoided creating a big lever arm.

[DanB]

It's beautiful...

I've just been reading the comments and JohnII suggested going to a 3 bladed prop.  I couldnt tell from your posting if your planning a 2 blader or not.

If so.. I would seriously re-think that!  Or put some weights on to make it 'act' like a 4 blader at least.  My experience with a two bladed prop on this type of machine with this furling system suggests that you'll have a disaster on your hands.  I think betweeen the offset, the loose tail, and the loose pipe over pipe yaw bearing you'll be astounded how badly a 2 blader is going to vibrate things when it yaws.  We tried that last year - it lasted for about 15 min (and it was scary) in moderate winds before the tail fell off.

Were doing a two blader now, (old wincharger prop) but I think the air brake will counter balance things to some point, and the tail will be rigid (not hinged).

So... if yours is a two blader I would maybe cut her in half and make one more...

[Ungrounded Lightning Rod]

I wouldn't sweat it too much. Even radial the strips are flat so they have lots of bending strength in directions corresponding to the rotation drag.  If they extend a way (like two or three times their width) across the flange and are welded along the edges they should perform more than adequately.

Offsetting them the way you describe would transfer some (not all) of the bending load into tension for one direction of rotation and compression in the other.  Transferring to tension is great.  Transferring to compression is rotten.  A thin strip is really weak and subject to buckling failures under compression.  (Better than either would be do do the spoke offset in BOTH directions, making a little V frame for each bolt support.)

But I wouldn't sweat it too much for something that's only handling a couple horses of "fluid friction" drag.

The main weakness is along the axis, and there's virtually no load in that direction.  (Unfortunately, even a minor offset that way risks letting the rotor drag on the stator, so you have to be sure it doesn't flex enough to let that happen - especially if a vibration makes it ring and build up a wiggle.)

[Ungrounded Lightning Rod]

I'm trying to [build a 120V DC system] and having some problems finding voltage regulators etc.

Voltage regulators?  I presume you mean "dump load controller", "DC circuit breakers", and maybe a "low-voltage cutout relay".  The batteries should do a great job holding the voltage stable enough to keep your equipment happy, as long as you arrange to keep from overcharging them and don't let them drain too far down.

A 10% variation in "line" voltage is not a big deal for most equipment (and only makes a 21% variation in power delivered to resistive loads like heaters).

[finnsawyer]

So, the question is, "Why not use bicycle rims in the design of a PM alternator?".  You mount a ring of iron in the rim's slot, then the coils, and finally provide another ring of iron around that.  Or the coils could be mounted to the outer iron ring.  I wonder if anyone has tried this?

[fanman]

hey smoggy

 i rounded up some pictures this morning for on my tower set up, like i said its 158' to the top of the generater, the gen that is up there is a homemade jobby, tis a combination of a jacobs blade activated governer and a permanemt mag radial flux generater, the magnets were ceramic 8 mostly because of cost, they do work good but the flux is minimal of course, and the blades are to heavy for the springs so it furls before it should, i get 20 amps quite easily from it, then it furls

i keep all the diodes at the bottom of the tower for ease of replacing them, you know when mother nature calls, and she does strike here quite often, and i have a couple capaciters in there to smooth out the waveform a bit

i built the tower on the ground and hinged two of the legs to the anchor so i could have it hoisted into place and it worked great, a crane picked it up and stood it easily

heres a shot looking up one of the legs of the tower, its pretty cool thing to up like that it almost makes ya dizzy,



theres a close up of the gen, you can see the stater in the back there, its 24 pole as well, i used half of a stack of lams from a 65hp electric motor for the stater about 4" thick 12"inside dia.



this picture is the whirlwind gen i have in the shop, ive heard alot of good about this machine, the furling does look like it wouldnt be acceptable, i thought that i would do the offset tail methode to it,

and there is one of my batteries i charge, they are 36 volt forklift batteries i got from a gm plant in texas, i split the cells up and rewired them for 120 volts boy they are used but very good shape yet, well there ya go smoogy i have more updates coming, im building the blades for my axial flux right now.

[fanman]

hey john 11

 yes i run 120 volt system and i love it, i really kind of stumbled upon a big com jacobs wind turbine, i was building a house here and the neighbor was out for a walk and asked me to come over for some repairs to his house, so i went over and i noticed a tower in his yard, and happened to ask what that was for and he said it used to be a wind turbine on it and that it was out behind the garage and had been there 30 years,let me tell you about three months earlier i was in the book store and home power magizene caught my eye,and it had a jake on the cover, i thought that was pretty neat so i bought it and was reading how these machines were the dinasuers of gen, and so on . well here i am now in this guys backyard looking at one of the dinasuers itself a 120 volt 3.5kw machine with the blade activated governer still attached, and it was buried half in the sand. what a find eh, i traded that man half of the repair bill for the gen, the governer, and a 6000 watt scr controlled inverter he had, it was approx, 240 bucks what a great deal, and thats when the generater bug got me, and ive been doing it eversince, any way back to the system, i really like 120 volt systems because there is no loses, i can use almost all garage tools on dc i can run all lights on dc, including any electronic ballast floresence light they sell at the home depot. the electronic ballast just rectify the in coming ac anyway, so why not run dc,you do need click type swithces on your shop tools or they will eventually burn out on you.

 but the one best thing about 120 dc is that i can make my own inverters to run the few ac things , like washer dryer,  tv, things like that.

 i do have plans that i will sell for $40.00 each it is a 4000 to 6000 watt mosfet driving inverter and is very easily to assemble all with radio shack componants, mostly the mosfets you must order from digakey, this is really a great inverter

the only one thing that it doesnt have is regulation, so if your batteries are at 130 volts so is the inverter, to me that is no big deal, tools and electronics can uasully take a great amount of fluxuation, ive been doing that inverter for about 6 years and have never burned a thing up with it, maybe im just lucky i dont know but it works great.it is modified square wave only. well  anyway john i have lots more to say but i have to go to town now,

[iwanamaka]

hi

It looks great, I am building a similar machine to run electric heat when the wind blows my heat away it will make more heat. I just finished machining my half inch plates (my new rotary table works great),next week I will glue and cast the magnets to the plates. I want to have 240 volt to power my heaters and I am making a 20 foot 3 blade prop, I will wind a 100 turn test coil and figure out my winding from there.

best of luck iwanamaka

[BigBreaker]

Turbines only spin one direction so its easy to keep the "spockets" under tension rather than compression.  Bicycle spokes use a V shaped push/pull configuration just as you suggest.

[BigBreaker]

Very nice setup.  Regulating the AC is MUCH easier if you start with a higher voltage that your AC peak.  Budget 50% higher DC than AC (RMS voltage) and you can use a PWM setup with your FETs.  That saves you a buck convertor or alternatively a transformer.

I'm glad your system is working but someone who could safely complete your inverter project could probably design their own on the back of a napkin.  Be careful who you give those plans to... 120 DC out of a battery is more than enough to kill a person!

It's safe to say that we all have tower envy.  My "tower" is 190 feet high and catches lots of wind.  Unfortunately my condo board won't take kindly to a big turbine mounted off my balcony!

Love the router jig for carving props - genius...

[jbear]

Fanman, if you do not mind I would sure like to look your system over and buy you a cup of coffee hey?

I live in Northern Michigan and would like to meet?  jbear@surfbest.net

[fanman]

hey jbear

fanman here, you say your in northern michigan eh? whereabouts in mich. i live manistee, brethren area, is this close? i just got my big axial flux up yeserday and i love the coffee so if you want to look me up feel free, let me know

[Nando]

DAVE:

I am including the message you post Jan/ 16/ 2006 where you indicate that you have a transformerless inverter that can handle 5000 watts.

Do you care to share the topology of such inverter, is this a choke flyback inverter ?.

A good description or even a schematic is appreciated.

Nando

~~~~~~~~~~~~~~~~~~~~~~~~~~~

Re: coils and magnets (3.00 / 0) (#2)

by fanman on Mon Jan 16th, 2006 at 05:01:14 AM MST

(User Info)

shadow i need a 120volt gen. because i live on a 120 volt dc system and it is a great system also i have no complaints about that, i understand that the gen only need to create 85 volts and because of the rectifacation and all will put it at 120 or so. also ive made my own inverter of 5000 watts, i did buy a inverter from exeltech that supplied 120 in and 120 out, very expensive and only 1100 watts, and guess what mother nature called and hit it with lighting, gone now i set out to make my own and i did, mosfet driven transformerless inverter that can handle a steady 5000 watt, and if hit by lighting 20 minutes tops to be back on line, but it is only modified square wave, but ive never had a problem with anything running,so there ya go shadow thanks much for the reply

fanman

fanman dave