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Forum Index : Windmills : New here. Lots of questions.

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readyakira

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Joined: 17/07/2008
Location: United States
Posts: 114

Posted: 11:47pm 16 Jul 2008

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New to the forums, but alot of interesting info here. I work in the used appliance field and when I saw a F&P washer come thru first thing I did was tell the boss I was going to destroy it for the motor. He didnt care much as in the states it is hard to get parts for these machines yet.

So anyways I removed the motor and thought I bet this would generate electric. I cut the wires and proceeded to hold 2 of the wires to my meter with one hand. needless to say when I spun the motor I got a pretty good jolt. I immediatly got hooked.

Now, I had wanted to make a windmill, and was collecting old dryer motors to pull windings out of to make the coils from. Problem was it was way too tedious to pull all that winding wire out. So the project came to a quick halt. So with my new F&P motor dream, I set off to look for info on making a mill of my own(or a relatives since I live in a relativly dense populated area).

First thing was for me to do some basic testing. I was able to conclude on my own that the motor was 3 phase similar to the alternator in a car. I also found rectified at a hand spun rpm, I could easily hit 200+vdc! So I got to posting on oupower.com of my new toy. I use oupower pretty extensivly for my HHO projects, and they have sections for almost any type of energy you can think of. When I posted first post was to here, and now I am hooked on this site! But after 2 days of research I have a few questions I have not found the answers to.

First is that I was wondering, if I make a mill to charge say 12v batteries, then it only charges when the voltage from the mill reaches over the batteries current voltage correct? (need enough pressure to push current back into the battery.) Charging a battery with 24v when it is a 12v battery I thought was a no-no and could damage it. so how do you regulate the voltage? and what controls the current it puts out?

I read about the dump loads, and realise as resistance to the flow of current goes down the mill will have a harder time turning. thus why people us the dummy loads. But to me that seems like a waste of energy. So I will look into heating water or something. But on that note as well, if you use it in a WH then what is to prevent it from boiling the water?

Another big set of questions is construction of the mill itself. when I removed the motor I cut the bottom of the tub out figuring I could heat press the top bearing housing out and use it in my design. has anyone tried using the bearings that are on the drive shaft? They should be water tight and designed for high rpms already. The do however seem to have a high amount of resistance, which I figure is due to how tight the seals probably are.

A finaly question is the stator is a 42design, which I believe is the "60" series? So if my understanding is correct the only way to overcome cogging problem and still produce a good amount of power is to use the newer magnet assembly. This is a problem for me as my part suppliers are very very limited on F&P parts. They are still relativly new here. So does anyone have a model number for the newer and older machines I can use for reference when looking for parts?

Weight wise has anyone had experience with using aluminum for housing design? Would it be strong enough? What about aircraft grade alluminum. this would reduce weight. But would the strength be enough.

Also most of the mountings I saw were just place a pipe on another. Is this better then if there is a bearing hub assembly used to allow the yaw adjustments?

So many questions...... For now I would just like to charge some batteries and maybe use that for some fans, and some landscape lighting. I have 12v-110 inverters at my disposal. but not really sure where to go from there.

EDIT: Sorry bout the format... was in a hurry and had so much racing through my mind!
Edited by readyakira 2008-07-18

Don't you think Free/Renewable energy should be mandatory in new buildings?

windlight
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Joined: 03/03/2007
Location: Australia
Posts: 331

Posted: 12:54am 17 Jul 2008

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Wow 30 lines in one paragraph, can you help dislectic people like me and edit that into some meaninfull paragraphs, thanks.

"I like this place and willingly could waste my time in it" - (Act II, Scene IV).

Robb
Senior Member

Joined: 01/08/2007
Location: Australia
Posts: 221

Posted: 03:29am 17 Jul 2008

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To fully charge a 12 volt battery you need to get it up to 14.4 volts.
When they hit 14.4 you need some way to prevent charging continuing or else you wont do the batterys much good and if they get to 16 volts or so you may damage your load devices (been there done that

).

You will find that when you place a load on the gen voltage will drop a bit due to internal risistance.

You shouldn't just disconect the wind generator or it may over rev and explode so you need furling or load dumping.

After you'v heated your water tank you could set it up to automaticly switch over to a fan forced air cooled load dump.

I believe a common cause of F&P washing machine failure is crook bearings so they may be crook.

readyakira

Senior Member

Joined: 17/07/2008
Location: United States
Posts: 114

Posted: 12:20pm 17 Jul 2008

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So if my understanding is correct if the low speed of my mill is 12v, then at full rpm the voltage will be higher, but, when you place it to a battery the voltage will drop and current increase when it charges the battery and voltage will go up and current decrease as the battery reaches higher charges?Edited by readyakira 2008-07-18

Don't you think Free/Renewable energy should be mandatory in new buildings?

oztules

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Joined: 26/07/2007
Location: Australia
Posts: 1686

Posted: 01:10pm 17 Jul 2008

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In simple terms.... yes.

From there it gets very complicated.

1. The impedance of the mill verses the impedance of the battery bank.... Getting this right is the difference between putting all your wind power into the stator and burning it out, or putting the power into the batteries where you want it.
You can hook a high impedance 240v mill into a 12v 500AH battery bank, the batteries will pull the voltage down to 13 volts or so,..... but most of the power will be burnt up as heat in the stator (and maybe the stator as well). The internal resistance of the mill is used to calculate what happens.
The battery is usually considered as a 13 voltish zener diode of approx 0 resistance after turnon (cut in).

2. The interesting relationship between the wind and the blades. This one is incredibly complex, and easily misunderstood and oversimplified.
At the same time it can be very forgiving and flexible. We can build properly designed blade profiles, and pretty ratty versions, and get little real difference in performance for the extra effort. Thats the forgiving side.

If we overload them then stall occurs. And everything in between stall and runaway is fair game, but with the cubic power of the wind and the linear nature of the voltage/rpms, matching it up is a headache. Usually a fair compromise is the best you can reasonably do.

3.We cannot just disconnect the mill when the batteries are fully charged, we must provide a dump load or alternative work load to stop the mill running to destruction. Not like solar where you disconnect the cells when charged. Unless manually furled or braked, the mill must have a proper load.

4. Matching point no 1. to 2. will give you a good system, happily harvesting power from the wind. A mismatch between 1. and 2. will see burnt out stators, runaway mills from poor loading, or poor output from stalling systems and everything in between.
So the alternator must be matched to the blades and the battery bank. Cutin rpm is critical to dictate the way the mill will perform. ie low cut-in stall controlled or free running high cut-in.

The fun begins now as you weigh up the pro's and con's of all the schemes that will enter your head from here on. There is much to research and lots to learn.

..........oztulesEdited by oztules 2008-07-18

Village idiot...or... just another hack out of his depth

windlight
Guru

Joined: 03/03/2007
Location: Australia
Posts: 331

Posted: 02:14pm 17 Jul 2008

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I will answer one point for you, the mounting pipe over pipe. Depending on the weight of the mill I adopt the following, a steady bearing on the lower end of the over tube with the inner race locked onto the inner pipe.

On top of the inner pipe a bush (brass/Lubron) or thrust bearing, if a bush provide some greater bearing surface than the pipe end has or it will chop out the bush.

On the other hand if the mill can yaw too freely it tends to follow the wind more rapidly, most times not good. Goes to using a bush instead of a thrust bearing.

allan

"I like this place and willingly could waste my time in it" - (Act II, Scene IV).

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