| Post Info | TOPIC: Stator for a Lenz VAWT |
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turnymf
Veteran Member
Posts: 39
Date: Mar 10, 2010
| RE: Stator for a Lenz VAWT |
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No inductor
One reason I stopped is my cro stopped, not because of the circuit but something in it's kv side driving the tube.
Where you thinking of ringing damping
cheers?
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sjh7132
Guru
Posts: 1252
Date: Mar 10, 2010
| RE: Stator for a Lenz VAWT |
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| turnymf wrote:
If I track it down I'll show it, but more than likely I'll be getting the bread board out and starting again
cheers
Cool. If you have trouble with the mosfets burning out, I'd suggest checking 2 things: 1) Make sure they are turned on fully. If they are partially on, they get really hot. 2) Make sure you don't exceed the rated VGS. That's how I tend to kill my FETs. :-) Did your circuit also use an inductor?
Steve
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turnymf
Veteran Member
Posts: 39
Date: Mar 10, 2010
| RE: Stator for a Lenz VAWT |
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| I didn't wire the stator Here is a link, mine would be a 80 series
http://www.thebackshed.com/windmill/WhatFP.aspAs far as the circuit goes I can't find it....it's been a while Basically I have a big electro on the bridges The battery sits on the other side of a mosfet For memory I used a op amp comparator to compare the big cap voltage to a reference preset v, say 35v When the comparator fired, a oscillator driven mofet switched the big cap's stored energy to the battery The circuits +ve ran off the big cap via regulators If I track it down I'll show it, but more than likely I'll be getting the bread board out and starting again cheers |
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keithturtle
Senior Member
Posts: 174
Date: Mar 10, 2010
| Stator for a Lenz VAWT |
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| sjh7132 wrote:
What is everyone else using for an alternator configuration on their Lenzs? And what wind speed do you need to start charging.
I'm asking because I'm having trouble finding any configuration on 10" disks, even using the big magnets, that will charge a battery in a 15 MPH wind and match the power of the turbine.
I figure the 3ft dia x 4ft Lenz is turning at 83 RPM in that wind and producing as much as 80 watts at the shaft.
I should have some approximate data eventually. The 9 ga 9", 5" centered disk on right was a stamping shop reject- I scarfed up several dozen from the dumpster. The polycarbonate indexer plates were milled on a turntable for accuracy, probably within a half degree. Coils go in the 6-hole plate; 1" round 1/2" neos in the 12-slot. I made these last year- just gotta get it all together. I intend to use coil pairs for 3-phase, total 6 coils. The flux alignment issue is addressed by three different diameters of coil to align with mags Turtle, slow -- Edited by keithturtle on Wednesday 10th of March 2010 12:41:10 AM
Soli Deo Gloria |
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sjh7132
Guru
Posts: 1252
Date: Mar 9, 2010
| RE: Stator for a Lenz VAWT |
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| turnymf wrote:
I have a lenz of about that size driving a unmodified fischer n parkel into a 24volt battery and the most I have seen is about 3 amps in about 40k turbulent winds
In light winds, the load holds the lenz to about 60 rpm (which seems to be about cut in for the f&p at 24v)
I have been trying to make a simple circuit that uses a rpm input to change the pwm output of a big cap sits on the main dc after the rectifiers via a mosfet into the battery
The same thing those little 12v solar panels the you put into the cig lighter socket of you car, the cheap ones with the flashing leds
Everything I have made so far I have managed to kill in testing, usually by pedaling to fast
O well
I'll get back to that
Cheers
Do you happen to know what you used for wire size, number of turns, and magnet size? If I had those I could use your numbers to verify my spread sheet. If you would like some feedback on your circuit, post it. I'm an expert in burning out mosfets and know just about every way to do it. (and now how to avoid it.)
Steve
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turnymf
Veteran Member
Posts: 39
Date: Mar 9, 2010
| RE: Stator for a Lenz VAWT |
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I have a lenz of about that size driving a unmodified fischer n parkel into a 24volt battery and the most I have seen is about 3 amps in about 40k turbulent winds
In light winds, the load holds the lenz to about 60 rpm (which seems to be about cut in for the f&p at 24v)
I have been trying to make a simple circuit that uses a rpm input to change the pwm output of a big cap sits on the main dc after the rectifiers via a mosfet into the battery
The same thing those little 12v solar panels the you put into the cig lighter socket of you car, the cheap ones with the flashing leds
Everything I have made so far I have managed to kill in testing, usually by pedaling to fast
O well
I'll get back to that
Cheers
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sjh7132
Guru
Posts: 1252
Date: Mar 9, 2010
| RE: Stator for a Lenz VAWT |
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| d3lilley wrote:
When my magnets are attracted to each other they have a pulling force of 53 pounds if that helps. I have no idea how to figure out the gausse rating. For future alternators, if I bought the magnets suggested would the alternator be fine?
What is everyone else using for an alternator configuration on their Lenzs? And what wind speed do you need to start charging. I'm asking because I'm having trouble finding any configuration on 10" disks, even using the big magnets, that will charge a battery in a 15 MPH wind and match the power of the turbine. I figure the 3ft dia x 4ft Lenz is turning at 83 RPM in that wind and producing as much as 80 watts at the shaft.
Steve
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Lohearth
Veteran Member
Posts: 46
Date: Mar 6, 2010
| RE: Stator for a Lenz VAWT |
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| Caleb wrote:
Lohearth wrote:
The general rule of thumb is total magnet thickness => air gap between the magnets
By "total magnet thickness" do you mean adding the thickness on both sides of the gap? So if I had two 1/4" thick magnets facing each other, I should have a gap of about 1/2"? Just checking to be clear; nice rule of thumb! Is there a similar one for thickness of steel behind the magnet?
-- Edited by Caleb on Thursday 4th of March 2010 02:39:06 PM
The two mag rule is the Max opening for the air gap. The way it was explained was as the magnets move farther apart, flux leakage increases. Once this distance becomes greater than the thickness of the two magnets, the flux will want to go to its own opposite pole rather than the opposite pole of the other magnet. That is why the air gap must be no greater than the thickness of the two magnets. Ideally, you want the distance smaller to get better flux and the flexibility to open the gap a little if it becomes necessary to better match the alternator to the turbine. If your final build is off a bit from what you expected, it's a good idea to have as many options to tweak it . That's why I prefer the idea of leaving the star points open The rotor test is to put a paper clip against the rotor behind the magnet. If it doesn't stick to the rotor, then your good. The thickness required for a specific sized magnet is something I would have to look up. |
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wiboater
Senior Member
Posts: 242
Date: Mar 4, 2010
| RE: Stator for a Lenz VAWT |
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No offense taken here. :) I wasn't really suggesting he use an inch airgap . I was wondering about those 1x1 magnets myself because the shape of the coils on my stators is wedge shaped to match the magnets. Kinda wondering how his coils are shaped and sized.
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sjh7132
Guru
Posts: 1252
Date: Mar 4, 2010
| RE: Stator for a Lenz VAWT |
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| wiboater wrote:
Just to be sure were all on the same page here. When I am saying a1/2 inch air gap I'm talking about the distance between the 2 magnet surfaces not the clearance between the stator and the magnets. I think your thinking about the clearance Steve.
Sorry, didn't mean to imply that any one person is crazy. I could see half an inch with large enough magnets. If there was a good rule of thumb it would be based on the minimum of the width or length of the magnet and the distance between magnets on the plate. If the gap is too large compared to these distances, then the field lines just curve around to the same magnet or to the magnet next to it on the plate. On this rotor the magnets are only 1" x 1". Those will need a small air gap. Does anyone have numbers for alts with thick stators? We could use them to figure out the field strength.
Steve
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Zapmk
Veteran Member
Posts: 49
Date: Mar 4, 2010
| RE: Stator for a Lenz VAWT |
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| sjh7132 wrote:
Lohearth wrote:
The general rule of thumb is total magnet thickness => air gap between the magnets
Not sure where that comes from. Ideally you'd make the stator as thin as you can and still fit the coils you need. (An alternative for larger coils is a bigger diameter). An inch air gap because you are using 2 half inch thick magnets is crazy.
I have seen this before, I beleave it was posted by Flux on OP, can't find the post right now. Crazy? maybe maybe not, real world testing is your best bet. |
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wiboater
Senior Member
Posts: 242
Date: Mar 4, 2010
| Stator for a Lenz VAWT |
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Just to be sure were all on the same page here. When I am saying a1/2 inch air gap I'm talking about the distance between the 2 magnet surfaces not the clearance between the stator and the magnets. I think your thinking about the clearance Steve.
-- Edited by wiboater on Thursday 4th of March 2010 05:23:59 PM
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sjh7132
Guru
Posts: 1252
Date: Mar 4, 2010
| Stator for a Lenz VAWT |
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| Lohearth wrote:
The general rule of thumb is total magnet thickness => air gap between the magnets
Not sure where that comes from. Ideally you'd make the stator as thin as you can and still fit the coils you need. (An alternative for larger coils is a bigger diameter). An inch air gap because you are using 2 half inch thick magnets is crazy. If this stator we are talking about has more than about a 3/8" air gap, there is no way it will charge a battery with a Lenz. -- Edited by sjh7132 on Thursday 4th of March 2010 03:38:19 PM
Steve
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Caleb
Senior Member
Posts: 473
Date: Mar 4, 2010
| Stator for a Lenz VAWT |
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| Lohearth wrote:
The general rule of thumb is total magnet thickness => air gap between the magnets
By "total magnet thickness" do you mean adding the thickness on both sides of the gap? So if I had two 1/4" thick magnets facing eachother, I should have a gap of about 1/2"? Just checking to be clear; nice rule of thumb! Is there a similar one for thickness of steel behind the magnet? -- Edited by Caleb on Thursday 4th of March 2010 02:39:06 PM
- Bryan
Mechanical Engineer turned stay-at-home dad. |
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electrondady1
Senior Member
Posts: 430
Date: Mar 4, 2010
| RE: Stator for a Lenz VAWT |
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ah, yes.
just trying to inject a bit of the old humor .
only simulated goats were harmed during the process.
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wiboater
Senior Member
Posts: 242
Date: Mar 4, 2010
| RE: Stator for a Lenz VAWT |
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That's what I thought, thanks.
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Lohearth
Veteran Member
Posts: 46
Date: Mar 4, 2010
| RE: Stator for a Lenz VAWT |
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The general rule of thumb is total magnet thickness => air gap between the magnets
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wiboater
Senior Member
Posts: 242
Date: Mar 4, 2010
| Stator for a Lenz VAWT |
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I'm confused about this 1/4 inch stator size. My stators are built from ed's instructions on his site and mine are 1/2 inch thick . There's no way to fit the coils I have in a 1/4 inch stator? I thought I saw somwhere that your stator should be the thickness of the 2 opposing magnets combined which in my case would be each magnet is 1/4 inch thick so, 1/2 inch stator. So if he has 1/2 magnets his stator should be able to be even a little larger thickness. I'm no expert on this though.
-- Edited by wiboater on Thursday 4th of March 2010 12:40:33 PM
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keithturtle
Senior Member
Posts: 174
Date: Mar 4, 2010
| RE: Stator for a Lenz VAWT |
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| electrondady1 wrote:
d3lilley,
i sacrificed a goat and read it's entrails
you are in big trouble
please check your profile for a private message.
i think you should sell all you have and send me the money.
That just ain't right. If you really want the answer, use a one-year-old lamb without spot or defect... <groan> Turtle
Soli Deo Gloria |
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Lohearth
Veteran Member
Posts: 46
Date: Mar 4, 2010
| RE: Stator for a Lenz VAWT |
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| d3lilley wrote:
When my magnets are attracted to each other they have a pulling force of 53 pounds if that helps. I have no idea how to figure out the gausse rating. For future alternators, if I bought the magnets suggested would the alternator be fine?
They usually give a gause number where you buy the magnets from. That would be greatly effected by how thick your stator is. The easiest way would be to make the rotor first and then make a test coil to see where your cut in would be and ajust from there. |
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Lohearth
Veteran Member
Posts: 46
Date: Mar 4, 2010
| RE: Stator for a Lenz VAWT |
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There are still too many variables to take into account. Unless some one has built an identical alt (or very close to it), it's still a guessing game with so much of the necessary info missing. The only way to know for sure is to test it once it's built
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d3lilley
Veteran Member
Posts: 49
Date: Mar 4, 2010
| RE: Stator for a Lenz VAWT |
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| When my magnets are attracted to each other they have a pulling force of 53 pounds if that helps. I have no idea how to figure out the gausse rating. For future alternators, if I bought the magnets suggested would the alternator be fine? |
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electrondady1
Senior Member
Posts: 430
Date: Mar 4, 2010
| RE: Stator for a Lenz VAWT |
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d3lilley,
i sacrificed a goat and read it's entrails
you are in big trouble
please check your profile for a private message.
i think you should sell all you have and send me the money.
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sjh7132
Guru
Posts: 1252
Date: Mar 3, 2010
| RE: Stator for a Lenz VAWT |
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| Okay, my 6000 Gause assumption might have been low. It might be closer to 7500 guass because your magnets are N42 and I calculated for N38. This makes your alt voltage and Ed's about the same. (12v RMS at 340 RPM). It seems low to me, but if it works for Ed, I guess it will work for you. Your current will be lower because you have smaller wire, and you'll put less power in the battery, but hopefully you'll get something. BTW the spread sheet for this is located HERE. See the second tab for alternator calculations. If it is wrong maybe someone can point out where. Steve
Steve
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sjh7132
Guru
Posts: 1252
Date: Mar 3, 2010
| Stator for a Lenz VAWT |
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How thick is your stator and can you measure the resistance?
Did Ed know the size if your magnets when he said this would be okay?
-- Edited by sjh7132 on Wednesday 3rd of March 2010 10:08:59 PM
__________________
Steve
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sjh7132
Guru
Posts: 1252
Date: Mar 3, 2010
| RE: Stator for a Lenz VAWT |
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| d3lilley wrote:
Alright here we go
Did you use Ed's magnets? If not I probably can't make a good guess. I don't think so. I am using 12 grade 42 1"x1" by 1/2" neodyminium magnets per rotor.
Is that 12 of these magnets per side or are you only using one plate of magnets? (or 6 on a side)?
Steve
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d3lilley
Veteran Member
Posts: 49
Date: Mar 3, 2010
| RE: Stator for a Lenz VAWT |
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Alright here we go
Did you use Ed's magnets? If not I probably can't make a good guess. I don't think so. I am using 12 grade 42 1"x1" by 1/2" neodyminium magnets per rotor.
2) What is the space between the plates or magnets? (or if you have the alt built, tell me the AC voltage on a phase for a given RPM.) I do not have it built yet.
3) Do you have the option to either use Delta or Star wiring, or is that connection already made internal to the stator? I already made a start connection internally.
4) Are you planning to make the standard 3ft dia x 4ft high Lenz or a different size? Yes I am, but if I have to make a bigger one to get the alternator I am building to work then I will.
5) What are your average winds? Do you mostly see 10MPH or 15MPH or what? I believe the average wind speed is somewhere around 8 mph but lately its been around 10-12.
I am sorry if I did not provide enough information. I emailed Ed and he said my stator should be fine, but I should test it. So if you are too busy please don't worry about it.
6) If you can, measure the resistance of one phase. Or give me a guess at how much wire went into the coils of each phase.
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wiboater
Senior Member
Posts: 242
Date: Mar 3, 2010
| RE: Stator for a Lenz VAWT |
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Your wrapping pape idea should work fine, If you have a little more aluminum at the end you can trim a little off. better over than undersize. If you build it to Ed's dimensions on his drawings a 48inch by 26 inch will be enough. If you go to the search feature on this site and type in bearings you'll find some sites to get bearings at. On Ed's 4 ft design you use 2 pillow block bearings. The size you need depends on your shaft. Mine is a 1 inch so you'd need a 1 inch I.D. ( inside diameter to slip over the shaft. You can start with one 4 ft turbine and if you need more you can alway's add a section on. It would be nice to know ahead what you need though because it would be cheaper to build one say 6 x 3 instead of 2 4ft sections stacked etc.
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sjh7132
Guru
Posts: 1252
Date: Mar 3, 2010
| Stator for a Lenz VAWT |
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| d3lilley wrote:
Hello,
Now I want to switch to a Lenz VAWT, but I have a few questions. I would like to know if I could still use the alternator I originally made for the HAWT. THe magnet rotors are 11 inches in diameter and each have 12 poles. The stator is the same exact design as the one suggested for the LENZ EXCEPT they used 14 gage wire whereas I used 18 and they gave their coils 42 turns whereas I gave my coils 75.
Thanks,
Drew
Okay I can't stand it. I thought I could be lazy and ignore this question but I can't. If you give me a little more info I'll tell you how your alt will do compared to Ed's standard. 1) Did you use Ed's magnets? If not I probably can't make a good guess. 2) What is the space between the plates or magnets? (or if you have the alt built, tell me the AC voltage on a phase for a given RPM.) 3) Do you have the option to either use Delta or Star wiring, or is that connection already made internal to the stator? 4) Are you planning to make the standard 3ft dia x 4ft high Lenz or a different size? 5) What are your average winds? Do you mostly see 10MPH or 15MPH or what? 6) If you can, measure the resistance of one phase. Or give me a guess at how much wire went into the coils of each phase. -- Edited by sjh7132 on Wednesday 3rd of March 2010 09:36:45 PM
Steve
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electrondady1
Senior Member
Posts: 430
Date: Mar 3, 2010
| RE: Stator for a Lenz VAWT |
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it's easy to get volts but tough to get amps
to get more volts you simply use more turns.
ed has given you a green light on the changes you've made so i wouldn't fret.
i don't know what level your building skills are
(they will be good by the time your done)
but i would make it as close to what ed has recommended as you can .
having said that, there are guys on the forum that are stacking them up and turning them in opposite directions,
all kinds of fun !
if you have doubts, just ask .
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sjh7132
Guru
Posts: 1252
Date: Mar 3, 2010
| RE: Stator for a Lenz VAWT |
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| d3lilley wrote:
I don't know if I will test it out though because if it doesn't work I am not making another stator. It would be too much time/money. So I would just re design the LENZ to fit with the stator. (making it bigger)
If you error on the side of too much voltage you might be able to use electronics to change the extra voltage into extra current. That's the purpose of an MPPT controller. Mine is still vaporware, but I am really working on it.
Steve
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d3lilley
Veteran Member
Posts: 49
Date: Mar 3, 2010
| RE: Stator for a Lenz VAWT |
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hey electro,
Yeah well as soon as I mentioned VAWT at the other power, they were very closed minded towards them. What they don't understand is that I am not living in some desolate, remote place where my power is contingent upon this wind turbine. I live in a more urban area and I just want this turbine to power a few appliances.
Anyways,
I was going to originally use the trailer hub with a spindle when I designed the HAWT. Now that I am going to make the LENZ VAWT, do I still use the trailer hub/spindle or to I buy some bearings? If so which bearings (fyi I have absolutely no experience with bearings. Somehow I managed to always use an alternative in every project I've done.)
As for the question about the stator, I resolved it. I emailed Ed and he replied saying that it should work, and might even be more efficient with this one, but to test it out first.
I don't know if I will test it out though because if it doesn't work I am not making another stator. It would be too much time/money. So I would just re design the LENZ to fit with the stator. (making it bigger)
Also, theirs been a few answers about the material used for the "skin" or the material used to cover the wings. Is aluminum the best option? and If so, could I get the exact dimensions I need by just taking some wrapping paper and covering the wings, and then marking off the area I used?
Thanks
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electrondady1
Senior Member
Posts: 430
Date: Mar 3, 2010
| RE: Stator for a Lenz VAWT |
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hey d3, its good to see you here.
you escaped other power with out getting skinned.
if you are using a trailer hub as you intended.
how were the stator support brackets tied in.
i have used a similar hub and the there is a stub that goes into a pipe to form the trailer axel.
so i used a lightly larger dia. pipe and welded angle iron to it for the support bracket.
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d3lilley
Veteran Member
Posts: 49
Date: Mar 3, 2010
| RE: Stator for a Lenz VAWT |
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| Alright I will test the alternator out as soon as I can. I am almost completely finished with it. 3 of my magnets that I was going to use for one of the magnet rotors broke, so I am waiting for 3 more in the mail.
When I do get the magnet rotor finish, how could I test the alternator? Do I just put it on a shaft and support the stator with something while I rotate the shaft? Then calculate the electrical output? |
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keithturtle
Senior Member
Posts: 174
Date: Mar 3, 2010
| RE: Stator for a Lenz VAWT |
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I have not had time to develop the ABS blades. I think there is potential there, but a lot of support is likely needed, like bends in the plastic and rib structures.
No time for it (ABS) right now; going with aluminum for the LENZ blades
Turtle
__________________
Soli Deo Gloria |
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Lohearth
Veteran Member
Posts: 46
Date: Mar 2, 2010
| RE: Stator for a Lenz VAWT |
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If the magnets are the same, then with a finer wire and almost doubling the turns,your alt will hit cut in much sooner. You might be able to go with a larger diameter for more torque.
The only way to make sure is to spin up the alternator and find the cut in speed for the voltage you want to go with and see if your available wind in your area will work. If you need more rpms, reduce the diameter, if you need more torque to turn it under load then build it higher.
Once you get the spec's of the alt worked out there will be a lot of people here that can help you out with the math to get you to a starting point for your dimensions
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d3lilley
Veteran Member
Posts: 49
Date: Mar 2, 2010
| RE: Stator for a Lenz VAWT |
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I found a source online where I can get them for about 25 dollars per wing. 48x26 are the exact dimensions that I will need if I follow the Lenz plan with all the right dimensions and everything? And is their anything less expensive then aluminum? I saw people talking about ABS plastic
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wiboater
Senior Member
Posts: 242
Date: Mar 2, 2010
| RE: Stator for a Lenz VAWT |
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I go to a sheet metal shop to buy my aluminum. .025 thickness is about $20. per wing, my first Lenz is built to Ed Lenz's size. I used a 4 ft. X26 inch piece per wing. The sheetmetal shop will shear them for you , sometimes they charge a cutting charge sometimes they don't. Usually only a couple of dollars. You can score it yourself with a razor knife and cut it that way also. They get the aluminum in 4X8 sheets. I'm not sure about your stator, I think it would work but somebody like Ed Lenz would have a better answer for you.
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d3lilley
Veteran Member
Posts: 49
Date: Mar 2, 2010
| RE: Stator for a Lenz VAWT |
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Just fixing one quick thing. I used 16 gage wire rather then 18 gage
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d3lilley
Veteran Member
Posts: 49
Date: Mar 2, 2010
| Stator for a Lenz VAWT |
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| Hello,
This is my first post on this site. I originally started to design a HAWT but then I realized that it is not practical in the more urban area I live in. I researched and found then a Lenz VAWT is very good for starting in lower wind speeds. I already had my HAWT design, just not assembled yet (with the alternator already made).
Now I want to switch to a Lenz VAWT, but I have a few questions. I would like to know if I could still use the alternator I originally made for the HAWT. THe magnet rotors are 11 inches in diameter and each have 12 poles. The stator is the same exact design as the one suggested for the LENZ EXCEPT they used 14 gage wire whereas I used 18 and they gave their coils 42 turns whereas I gave my coils 75.
Will that difference make my stator completely in effective? If it does could I just build my LENZ bigger or smaller then the plans call for to make up for the difference?
additionally, for the lenz blades, what is the best material to use for the "skin"? The website suggests aluminum sheet or pvc sheet but when I checked the prices both are pretty expensive.
Thanks,
Drew
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