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Forum Index : Windmills : AC or DC for distance
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MacGyver Guru  Joined: 12/05/2009 Location: United StatesPosts: 1329 |
Oztules "AWP"? While I'm at it, I already asked this somewhere else (?) but what's a "bit"? I already know about the twisty-drills, the one in the horse's mouth and its reference to a "quarter" in American money; what's it mean in Australia? . . . . . Mac Nothing difficult is ever easy! Perhaps better stated in the words of Morgan Freeman, "Where there is no struggle, there is no progress!" Copeville, Texas |
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oztules Guru Joined: 26/07/2007 Location: AustraliaPosts: 1686 |
Ok Mac, It is a radial flux windmill. I have done stories for it here, and here and here... you will find a few more in my profile page. Because of where it is, it will easily do 24kwh per day and lots more. Karl would be happy with this I suspect. It uses ferrite magnets, iron core, and is everything I try to avoid..... but as Pete says, sometimes it just works. I think it is designed by Hugh Piggott, who also made the AXFX a mainstream item... I smart windmill man indeed. It would be my pick of windmills if I had to buy one. ...........oztules Village idiot...or... just another hack out of his depth |
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GWatPE Senior Member  Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
Good luck buying an AWP. A mate has paid good money up front for one and is still waiting after a year. There has been a difficult transition to a NEO rotor without success. Gordon. become more energy aware |
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niall1 Senior Member Joined: 20/11/2008 Location: IrelandPosts: 331 |
mmm.... at a risk off opening a can of worms here there was a small thread tail on fieldlines where a proven machine was opened up for maintenance and revealed what made it tick.... from what i could gather everything about it seems to push the conventional thinking about axial flux machines a little further .... the stator seemed to have a laminate based core with toroid windings ?... and seemed to need jacking screws just to get the thing on....also and more weirdly it seemed (according to the post) to use big ferrite based magnets i wonder if theres an argument here for taking a breath and going back from the trend of using neo based magnets ....yes a laminate stator does just seem wrong...but the ferrites ? ferrites (or better) seem to have drifted well below the radar .....but there going to need a market somewhere..... niall |
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| oztules Guru Joined: 26/07/2007 Location: AustraliaPosts: 1686 |
Simplicity and low wind startup are the hallmarks of the axfx. It produces in fragile winds very well if thats what you wind for. It is so versatile, that it is the best for a home brew, made from scratch mill. I quite like the AWP style, and if I were a manufacturer, I would not make the transition to neo based machines.... unless I was trying for lots of power in a small diameter alternator.... ah la motor rewinds like Bryan has done. There you need all the flux you can get. But, if you have access to laminate stampings of the size required for the mill you wish to make, it is as good a way as any, with almost no drawbacks.... except braking, and some iron drag.... and with ferrites, it is not too bad. Those that have used neo's with the seeley or the F&P appear to have not been that excited about all the extra work and drag, just to get a bit more on the top end If you put 30 big neo magnets on the AWP, you'd be scratching to make it turn..... Jamie has asked me about doing that.... and I flatly refused. True, it may not make quite as much as the axfx version of similar design parameters, but what it loses there it will make up with sheer toughness, and no magnet problems. For a manufacturer I would see these as very strong arguments for steel based machines. It is not hard to saturate the steel with ferrite, and so any flux you pay for after that, behaves as though the steel was not there, so you still get advantage, but it is severely curtailed, as the coils will be down the slot a way, and the flux will no longer link the excess flux through the coils as it did when the steel was the flux carrier. However, if you are going to make a radial drum type like this one: 
then you need Neo's if you want some kw power. It gets away with this because the air gap is quite large (12mm?)compared to normal iron core practices (1mm or less), so the drum drag is not too bad. So, yes, Neo's are not for everyone, and some designs I feel will be nicer without, but to get more power density in smaller alts, then we start to need higher flux fields dt do it. I can't see an AWP doing well with neo's, unless it is completely re-designed, otherwise startup would be very high, and rpm range very tight. It is fine as it is. ............oztules Village idiot...or... just another hack out of his depth |
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KarlJ Guru Joined: 19/05/2008 Location: AustraliaPosts: 1178 |
OZ, indeed I would be happy with 24KW/day!! and the transformer you show for the AWP, that would make one kick ass microwave eh? Have you ever thought of building a 20KW microwave WOW, hot pie in 5-10 seconds melt glass in a minute or two. mmmmm the fun you could have! Luck favours the well prepared |
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| oztules Guru Joined: 26/07/2007 Location: AustraliaPosts: 1686 |
Cavity resonant magnetrons are not that easy for me to get up to that power level. From memory, "large" magnetrons of 2 or more megawatts.... are water cooled and pulsed with very short pulses, and so even then only generate a 3-4kw average..... (bit like an electric fence I guess in that way) not sure if just upping the voltage and beefing up the permanent magnet will do the trick. Cathode design will need to be changed too I reckon. The cavities may well stay the same, but the electron density must go up... So I don't think I'm up to the challenge. I like the 5 second hot pies idea, but can't see how you can heat the glass without water molecules present. I know CR magnetrons are notoriously wayward frequency generators.... but I don't see glass heating in the mix. 
.............oztules Village idiot...or... just another hack out of his depth |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Karl Did you want to heat the pie or blow up the pie? that sort of energy would blow the fat molecules in a couple of seconds and melt down the solar panels. We had a plastic welder ex GMH that would be suitable, but would wipe out all the TV in the area. Still have the tranny in the shed 100 amp input and 2500 volts out. All the best Bob Foolin Around |
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| KarlJ Guru Joined: 19/05/2008 Location: AustraliaPosts: 1178 |
LOL you guys are great! apparently a "normal" microwave will make glass, google it for some giggles. dont know that i'd give it a try in mine. 
nothing ever as simple as it appears. Now that OZX is about i'm based at RISE Murdoch university. they have a 30KW westwind and all its power goes to a dump load as the manufacturer of the inverter disappeared many years ago. I mentioned I knew a bloke (thats you OZ) that could fix basically anything. are you interested in giving it a crack? obviously it would take months for them to come up with the funding just to get it to you but I see some promise. Luck favours the well prepared |
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| oztules Guru Joined: 26/07/2007 Location: AustraliaPosts: 1686 |
Eeeek... 30kw.. I suspect that this thing is a huge double filing cabinet sized thing with a transformer weighing about 100kg... 3phase. I had the opportunity to look at a westwind installation over at Cape Barron Island. (small community south of here). It will take you a long time just to extricate it from the generator electronics and the inverter electronics. (if it drives a battery bank) From memory it was a big 3 phase unit made up of three slave single phase units under the control of a master computer that co-ordinated the three single phase critters and gave you your 415v 3 phase output... this then "was" the grid over there. Fixing it without circuits will be difficult.. but not impossible, but fixing it without having the paper work that describes the interfacing with the ancillary equipment may be next to impossible.... This means that although you get the pwm sections running and fixed, the computer may be looking for a series of events to be in place before it will allow the unit to fire up. If we don't know what these inputs are, it may never start again, even though the power side will be technically fine..... why I hate computer controlled pwm units. Good things about it..... you have three identical slaves to work with, so the chances of fixing these power circuit problems is very high..... something for your electrical engineer undergraduates perhaps.... Bad things.... if the problem was originally in the master controller, we may never know how it worked, and as the control pulses will come from there. We will probably not get it to run again, even though the power section will be fine as we will not know what inputs it needs to see to fire up.... perhaps a problem for the computer science kids to build a new master driver. A few photo's may help a little, and there are brighter folks than me here to look at them, and maybe some who have actually played with them. I wouldn't mind having a play, but I suspect these things need a forklift, and a few thousand dollars to get to this end of the universe from there..... and no guarantee I would be even able to test the unit out.... I have no 30kw source @ X volts DC.... slight problem. I was offered the unit from Cape Barren, but decided against it for all of those reasons....and what to do with it, if and when I got it going..... If yours is a grid tie inverter.... I have no 415v three phase either. only 240v 3 phase I create from the 240v single phase. So interesting project, but success looks distant at this stage. I haven't checked google yet, but was under the impression that the microwave only vibrated the water molecules.... (why pyrex and other water inert substances do not respond to the microwave energy). Will have to look into this when I get time.... ..........oztules Village idiot...or... just another hack out of his depth |
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| MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
Oz What would pwm units and pwm sections translate to in English? . . . . . Mac Nothing difficult is ever easy! Perhaps better stated in the words of Morgan Freeman, "Where there is no struggle, there is no progress!" Copeville, Texas |
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Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Mac, PWM means ...Pulse Width Modulation....which is referring to adjusting the Duty Cycle or the width of a pulse within a given time period. For instance if the output when high for 50 milliseconds and low for 50 milliseconds we would have a Duty Cycle of 50% in a 100 millisecond Period. By adjusting the duty cycle within a period, we can increase or reduce the power output. Pulse means it swings high and low. Width means the % of the duty cycle. Modulation means adjusting or changing. Have i confused you yet?? Perhaps Oz can explain better. Pete. Sometimes it just works |
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| oztules Guru Joined: 26/07/2007 Location: AustraliaPosts: 1686 |
Thats good Pete.... but I have found Mac likes to have a plumbing flavour introduced... so I will try this angle. Mac, If we had a conveyor belt passing in front of us, full of buckets side by side, going past at a fixed rate. We can say we have say 50 buckets per minute passing us. Now this conveyor empties these buckets into a tank at the end of the belt, and the cycle continues. If we have no water in the buckets, they still empty into the tank, but no water goes into the tank, coz there is none in the bucket.... but we keep on going. If we were to 1/4 fill each bucket at the source of the belt, we would see a procession of 1/4 full buckets going past, and dumping these 1/4 full buckets into the tank, the tank fills at that rate.. that rate being 50 buckets per minute X 1/4 for the bucket, will give you the amount of water going into the tank. If we 1/2 fill them, then twice as much water gets into the tank in the same time. If we fill the buckets, we get 50 full buckets of water in the tank each minute. So by changing the amount of the bucket that contains water, we change the flow rate. When each bucket has no water, we say it has 0 duty cycle. The buckets still pass, but nobody's home. It follows, that as we half fill the buckets, we have 50% duty cycle, 3/4 full would be 75% duty cycle, and full buckets will be 100% duty cycle... or fully utilised, or a maximum water flow
So the pulse can be the buckets. The duty cycle is how full they are. We can change the flow rate (modulate) by changing how full the buckets are (pulse width). But we keep the number of buckets moving past constant (frequency) There.... it involved water at least... ............oztules Village idiot...or... just another hack out of his depth |
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| Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Very good Oz, but my mind boggles on how they can fit those tiny conveyor belts and all those buckets of magic smoke into those iddy biddy little packages. 
You could say that is a wet answer you gave, but i like the KISS theory. 
Plumbing is a downhill slide, and guess old habits die hard. Pete. Sometimes it just works |
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| MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
Thanks Oz; that makes it crystal clear for me. [Quote=Pete]Plumbing is a downhill slide . . . You're 25% on your way to being a plumber, mate! There's only 4 "rules" to my job and you've just hit on the very first one, *&#@ flows downhill!
. . . . . Mac Nothing difficult is ever easy! Perhaps better stated in the words of Morgan Freeman, "Where there is no struggle, there is no progress!" Copeville, Texas |
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| grub Senior Member Joined: 27/11/2007 Location: AustraliaPosts: 169 |
MacGyver said, "*&#@ flows downhill!". I thought it was "Water flows downhill, but it ain't always water". Are you familiar with a "Bondi Cigar"? Very common around sea outfalls. |
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