Author Topic: My Lenz Tubines (Read 6996 times)

wayne · « **on:** October 17, 2005, 07:27:46 PM »

Hi

Been out of the picture for a year as building my house. Keeping up to Ed's great work or trying to. The small one on white little tower is just free running and runs in a slight breeze. The bigger one is not done yet and now have top/bottom plates with generator on bottom. It has 16 magnets and 12 coils. Wired up as 3 phase. Spin by hand get about 2 volts. Having problem keeping the steel plate horiz to coils and have a gap which is too large. Fixing this then hope tie it to top of van for a drive.

Wayne

wayne · « **Reply #1 on:** October 17, 2005, 01:28:35 PM »

wayne · « **Reply #2 on:** October 17, 2005, 01:29:04 PM »

Ungrounded Lightning Rod · « **Reply #3 on:** October 17, 2005, 02:34:08 PM »

Having problem keeping the steel plate horiz to coils

Try running the shaft through the bearing to at least the rotor's height below the genny, then put another bearing there to take the side force. That's equivalent to putting a bearing at the top, without requiring a structure around the rotor to impede the wind.

Of course you DO need a stiff shaft or it will bend. So you'll probably need to make your shaft bigger. (Or substitute a piece of pipe: essentially all the strength is near the surface anyhow, so why bother with all that weight in the middle? B-) )

The wind going around the shaft may affect the performance somewhat, but not necessarily in a bad way. (I recall Ed's early designs had a big cylinder there to speed up the wind as it passed the blades.) You might get an improvement. You'll probably get a tiny change to the ideal radii and angles for the blades.

windstuffnow · « **Reply #4 on:** October 17, 2005, 05:06:06 PM »

Nice job Wayne ! I agree with ULR, I think you'll need a stiffer shaft in the larger one to keep it stable or like I did my 3x4 with an H frame and bearing top and bottom.

What did you use for sheet to form the wings? What size is the larger one?

I just finished a 2x2ft thats going to the wind tunnel in a week or so, been playing with it and it seems to do fairly well but not as well as it should.... or as well as the others. The only thing I changed was the way the trailing edge was made making it cleaner, allowing the air to flow smoothly. My larger one has a bent end and is very dirty in the air, seems to work quite well that way. The original one is like yours, just a clean flat trailing edge and works great. I've had to change the wing angle to get the newest one to perform. There is a secret waiting to be discovered somewhere in there!

Once again, Great work ! Let us know how it does.

.

wayne · « **Reply #5 on:** October 17, 2005, 05:46:28 PM »

Thanks for your nice comments Ed. Its a start for me from my little ones. This one is 18" dia and 2 feet height. I have a 5 degree angle on each one. Can't see this on pic. I used cheap aluminium flashing for roofs to cover it. Bends easy. The shaft is only 5/16" and is the weak link. I used this because I had some roller bearing laying around looking for a home. Might be too small. Hope to fix it and test on sunday.

Thks

Wayne

rotornuts · « **Reply #6 on:** October 17, 2005, 07:11:48 PM »

Hey Wayne, the last vertical I built was 12 x 26" and I used a 3/4" shaft. The bearings at the base are 6" apart (two of them). It's a strong setup. I worked up to that from shafts that where too small so I would recommend 3/4" shaft. Seems big I know but it doesn't cost much more than 1/2" and it gives it the rigidity you want.

Mike

ozetrade · « **Reply #7 on:** October 17, 2005, 09:02:58 PM »

Hi Ed,

I'm new to the forum and wind generation. Do you think something the size of Waynes VAWT would drive a F&P that has benn decogged? Would I need to gear it to get the RPM's up?

Greg

windstuffnow · « **Reply #8 on:** October 18, 2005, 07:48:28 AM »

Hi Greg,

I've never had the opportunity to work with one of the F&P units so I have no experience with them. You would need to measure the amount of force required to start the F&P machine turning. My 2ft diameter x 2ft tall machine provides 500 grams of force in a 10mph wind measuring the locked rotor force.

.

fukenfooser · « **Reply #9 on:** October 18, 2005, 08:42:15 AM »

How do you measure the force?

tie a scale to the unit and see what it pulls to?

windstuffnow · « **Reply #10 on:** October 18, 2005, 09:45:38 AM »

I use a science scale incremented in grams which I later convert to lbs to find ft lbs. You simply attatch the scale any way you can to the outer diameter and take measurements at different positions. I usually take several measurments over a 90 degree turn and average them out to find start up torque. It doesn't tell you what the machine will do while its running only start up torque.

.

electrondady1 · « **Reply #11 on:** October 18, 2005, 10:07:32 AM »

congrats wain , nice vawt. looks like your on the right path.!

wayne · « **Reply #12 on:** October 19, 2005, 08:27:56 AM »

Hi Mike/ Ed

Thinking now of using 3/4" shaft and using two plates 6" apart with bearings. Then no top support which might be better. I went out to auto stores and asked for bearing and got the run around O.D, I.D bearing loading, what type? And on and on. Mike do you have any pics of your support I could see and what bearings should I use.

Thanks

Wayne

windstuffnow · « **Reply #13 on:** October 19, 2005, 12:06:00 PM »

Hi Wayne,

Look on ebay... people sell some very inexpensive bearings. I've made bearing hubs out of plywood using a hole saw the same od as the bearings ( sometimes adding paper or cardboard to "shim" them in tight ). A 3/4" plywood box makes a very strong bearing hub and its quick and simple. Also, you can get some reasonably inexpensive bearings ( and shafting ) from Enco ( http://www.use-enco.com ) They're great people to deal with and fast shipping.

For your project, I wouldn't worry about using specific bearings, simply tell them your looking for an id of 3/4" the od can be worked into the design. Personally I go for the least expensive ones. Inch size bearings are typically more expensive then the mm sizes but there are some out there that are very reasonably priced.

.

Norm · « **Reply #14 on:** October 19, 2005, 03:26:43 PM »

The front fork assembly from a bicycle makes an

excellent bearing assembly .....or the back wheel

for the bottom and the front wheel for the top...

all kind of bicycle bearings suitable for windmills.....

( :>) Norm.

rotornuts · « **Reply #15 on:** October 19, 2005, 06:19:27 PM »

I should tell you I'm actually running on bushings with a single point bearing(a pin(screw head actually) to carry the axial load. I found some overhead cam lifters that fit a 3/4" shaft perrrfectly.

A fliudfilm bearing works remarkably well once you get the alignment right. The only problem is a verrry slight increase in start torque is required to get the shaft "floating" in the journal. The single point bearing to support the wieght of the rotor works like the bearings in a watch and I'm also very suprised at how well it works. The rotor runs totally silent and vibration free. You can place your ear up against the support and hear nothing at all when it's spinning. I guess the other problem is the need for re-oiling the bushings and the point load will wear quickly.

Solvable problems but I'm afraid to go there right now for fear of getting off track yet again.

Like Ed said go for the cheap bearings for your experiments and I could be wrong but I wouldn't worry about axial loading with such a small load (just get a regular straight bearing not the tapered bearings). You'll just need a collar or two.

Mike

inode buddha · « **Reply #16 on:** October 19, 2005, 10:29:55 PM »

The shaft is definitely weak IMHO. I would try 3/4" steel pipe. As for the plates you could probably put stiffening "spokes" or ribs onto the plates in a radial pattern. Thick plate (say at least 3/8") would work but they would take too much force to start spinning I bet -- too much inertia.

ozetrade · « **Reply #17 on:** October 22, 2005, 05:35:45 AM »

Thanks for the reply Ed,

Most of the information I have been able to find comes from http://www.ecoinn.co.nz They state in this file http://www.ecoinn.co.nz/pdf/smartdrive_wind_turbine.pdf that the Cogging force in grams measured at perimeter of rotor for an uncogged stator is 900-950. After the stator has been decogged, it is 450-500.

Based on what your reply was, I would need to build one a bit bigger if I want it to start in lighter breeze - any suggestions for a starting point?

I have rewired mine as an 80SP which is supposed to start generating usable watts a 250-300 RPM - well enough for me, I'm only looking to keep a single 120A wet cell deep cycle charged that has a constant 5.5-6A draw on it. (graphs at the bottom of this file http://www.ecoinn.co.nz/pdf/smartdrive_what_is_it.pdf).

Also, since I'm not really comprehending some of the settings you guys use mentioning, I was going to make my wing adjustable and measure any RPM differences.

I also thought of an idea, since kitno455 mentioned it here(if we could only get rid of the downwind blades - http://www.fieldlines.com/comments/2005/8/18/19637/0978/7#7 ). This modified diagram of yours will describe it better.

As a newbie, I'm probably treading on covered territory, but I'm going to try it.

BTW, I am building to your current design. The above image was the easiest to find and use to describe my idea ;-)

Greg

ozetrade · « **Reply #18 on:** October 23, 2005, 04:45:25 PM »

Thanks for the reply Ed,

(Admin - Sorry for the double reply, but I realised after I did the first one that it wasn't a reply to Ed's reply, but to the original poster. Assumed Ed would not be aware of my reply.)

Most of the information I have been able to find comes from http://www.ecoinn.co.nz They state in this file http://www.ecoinn.co.nz/pdf/smartdrive_wind_turbine.pdf that the Cogging force in grams measured at perimeter of rotor for an uncogged stator is 900-950. After the stator has been decogged, it is 450-500.

Based on what your reply was, I would need to build one a bit bigger if I want it to start in lighter breeze - any suggestions for a starting point?

I have rewired mine as an 80SP which is supposed to start generating usable watts a 250-300 RPM - well enough for me, I'm only looking to keep a single 120A wet cell deep cycle charged that has a constant 5.5-6A draw on it. (graphs at the bottom of this file http://www.ecoinn.co.nz/pdf/smartdrive_what_is_it.pdf).

Also, since I'm not really comprehending some of the settings you guys use mentioning, I was going to make my wing adjustable and measure any RPM differences.

I also thought of an idea, since kitno455 mentioned it here(if we could only get rid of the downwind blades - http://www.fieldlines.com/comments/2005/8/18/19637/0978/7#7 ). This modified diagram of yours will describe it better.

As a newbie, I'm probably treading on covered territory, but I'm going to try it. I'm thinking that as the wind hits the back of it, the blade will be forced to a more accute angle and actually acyt as wing and generate power rather than resistance. At worst it may spark some new line of thought. :-)

BTW, I am building to your current design. The above image was the easiest to find and use to describe my idea ;-)

Greg

windstuffnow · « **Reply #19 on:** October 24, 2005, 08:00:29 AM »

I've run into a couple oddities on the newer versions. The control system you have there may take it from good performance to better as the wind pick up. Originally I thought it would make the wings a bit more dirty by changing the angle. In reality it changes the angle that the power pulse occurs. By changing the wing angle closer to the 0 degree mark will actually speed it up. This is still in its early testing stages but the control system may actually help not hinder as I thought earlier.

.

wayne · « **Reply #20 on:** October 24, 2005, 02:22:17 PM »

Hi All

Thanks for all your help and hope to change shaft/bearings this weekend. I was sent away for a week so had no time. Will post a update once its running and pics. Hope more will try Ed's Lenz and different mods and have a great VAWT.

Wayne

wayne · « **Reply #21 on:** October 31, 2005, 11:46:54 AM »

Hi

I finally got a new 3/4 SS shaft and two bearings at bottom. This seems really good and no wobble and very solid. So on sunday took it for a drive. When I spin by hand the output is about 2-3 volts. As I drove to 5mph the turbine would not turn and seems to lock, and as I drove faster it finally unlocked and spun. Not happy here and maybe the angles are not right. My little one turns in a slight breeze. As for power to charge 12 volt battery this was about 15mph at about 3.5watts. Very sad with this after all the work. The turbine is not spinning fast enough I guess. So have 2 problems now is need low RPM gen and fix the stall problem. Back to drawing board again.

Wayne

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Author Topic: My Lenz Tubines (Read 6996 times)