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Forum Index : Windmills : Smart Drive build USA Tough
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BobMann Senior Member  Joined: 30/06/2011 Location: United StatesPosts: 134 |
Perry I will re chech with him on it. What am doing now is going forword with my back yard wind tunnel. If you follow my Mann Smart Drive you will see I can make big power at low speeds. So best for all is just do the wind tunnel test and be don with it. I can and do pull power from low dirty air with my turbines. This a hobby to me at this point a small start-up lets say. just because the air is slow and dirty don's mean we shouldent try to suck the live out of it. bob Mann |
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MacGyver Guru  Joined: 12/05/2009 Location: United StatesPosts: 1329 |
Bob, Perry, et.al. That turbine pictured smacks of an Ed Lenz design. Has anyone contacted Ed or looked on his Web site to see what kind of power his units make? Seems to me there's an article here on The Backshed somewhere using that same design; same color too, as I recall. Maybe I'll have to reasearch it myself when I've the time. If there are production numbers, maybe they could be compared to the figures stated here and clear up some of this mess, eh? Just curious, that's all. Edit: Bingo! . . . . . 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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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi All I have been following the line of thought for a while now and have noted the proposed output from the unit in the early posts from Bob. the figures quoted are realistic for the lower wind speeds most town blocks would expect to get, and in reality would save very little money in real terms compared to our so called normal power usage, around 32 to 35 KW per day when the mill is doing 1 KW per day assuming 24 / 7 wind supply a return of 25 cents a day in my case at the cost of power here in SEQ. As we all know the wind is a fickle thing so if it blows a third of the time we are doing well so that equates to $30 a year approx, this applies to all wind devices that are small. This includes WAWT and HAWT, so to be realistic wind energy in small devices is a commercial failier, but a very interesting hobby. Unless you have a wind reliability factor of 70 percent and a velocity of 6 + MS it cannot be a commercial proposition with a small machine, you need a big machine to get usable energy, that is just physics, but it doesn't stop us trying to do better and enjoying our hobby. The main problem is our expectation, we want to run, the pool pump, the entertainment system, the electric stove, a microwave oven, a toaster, coffee machine, deep fryer, two fridges and a freezer, heating and cooling air conditioner, a multitude of so called electrical labor saving devices, a washing machine, a dryer, a computer sitting on line all the time lights that are left on most times, and are a fashion statement rather than practical, TV running with nobody watching it most of the day, hair drier hair straightener spar bath sauna and it goes on and on. We then complain about the cost of electricity while wasting 80% of what we pay for. If we want to save money look at the consumption rather than the generation. In my past experience a VAWT needs to be at least 12 ft high and 10 foot in diameter to provide basic electricity for a house on a 32 volt system. Sorry Bob but your small machine will be useful only if you can get 10 MS wind most times then it may put out 2 to 3 KW a day, but even that is only useful if the use is heavily reduced. All the best Bob (Morgan) Foolin Around |
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niall1 Senior Member Joined: 20/11/2008 Location: IrelandPosts: 331 |
this may well be an urban myth ...but i think it happened here...at least i read about it ...doesnt make it true though long time back the esb (our power company) did a small study with "micro wind" basically they put a grid tie wind turbine on a selected 2 adult 2.3 kids average household to see what the results would be... the turbine was a complete failure....nothing new there .. but the rub was the family actually got clued in to the mill and tried to cut down on their general power requirements ... even if its not true it enhances the power of mills a bit..all be it in an odd way niall |
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| BobMann Senior Member Joined: 30/06/2011 Location: United StatesPosts: 134 |
Sorry Bob but your small machine will be useful only if you can get 10 MS wind most times then it may put out 2 to 3 KW a day, but even that is only useful if the use is heavily reduced. All the best Bob (Morgan) Thank you the plan was all was to go bigger. The Smart Drive is a very good unit. That is why I am building a round it. I just find the lenx wing to work very well with my MODs in dirty air. I have blown up many a part and burned a lot of cash over the 2 years. Lets look at it this way the Mann Smart Drive is a steel drum and hub good for 3500 of bearing load 24/7 and can be pushed x3 if needed. With a depth of 2 1/2 deep it will hold 2 38 poll stators Can be mounted on a 2 inch pipe slip fit I can make up any neomagnet compontion that I wish The sign wave is perfect on the labscope Has a 5 on 4 bolt hole stud flange can be used as a VAWT or a HAWT can be build in three hours and boxed ready to go. My Tree Top Wind Mill only weights with the Mann Smart Drive 85 LB ready to go. Now lets look at the wings they are water jet cut all alumanim hard to build cost a lot and take time to build if we go injected molding we can cut wing cost down by 400% I think you know what the mold runs ?? if made right 4 ft long by 1 ft wide and made to snap on end to end and bolted to gather.I will be able to go 4/8/12/18 high and add 3/4/5/6 wings to a unit and still use just one Mann Smart Drive to make cheep power and be used any were in the world that needs it at a very low cost per unit. Just a plan Bob Mann Bob Mann |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Bob I like your concept and really like the modifications to the F&P motor as it will make it twice as powerful and be a good base for many projects in low consumption systems, I was just pointing out that some people expect too much of a windmill as a money saver device, I see the use is where there is no power at all and if it can run some LED lighting a small radio and charge the mobile phone that is an enormous benefit to a subsistence power user. In conjunction with a solar panel system it could be upgraded to a really useful to rural dwellers system. The up scaling of the unit will be the most important, and believe me the bigger the better in a VAWT as in all mills as the bigger the area the bigger the power capture. If I was 20 years younger I would be building VAWT as I did 40 years ago, the mills worked well then but the cost was the killer, things have changed now with inflated power prices. As I am retired and trying to live on a feeble pension it doesn't let me play to much with larger and costly mills. When you go bigger you will find that the smart drive is a bit small for peak loading, on the ones I was building I had 42 volt generator at 200 amps and at times it was overloading, I built a purpose made generator that could do a maximum of 500 amps 42 volts, but the whole thing got to expensive for the then existing market, then the rural SWER line system was introduced with a very cheap power on the condition that the farmers decommissioned their 32 volt systems, now we are going the other way so good luck with yours. All the best Bob Foolin Around |
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| BobMann Senior Member Joined: 30/06/2011 Location: United StatesPosts: 134 |
Hello Thank you for your kind words. Some just do not get me. That was a plan some huts have nothing . Just think a few LED bulb, So there childing can read at night. So they can learn and change there oun world. Bob Mann |
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Perry Senior Member Joined: 19/11/2009 Location: Posts: 190 |
Well we may not agree on what it means to sell wind turbines on the open market but I must say you certainly do have a vision and passion for what you do. Don't take our conversation as me crapping all over your work. I just like to do the math and look at the data to see how turbines perform. Maybe I'll build a similar gen, looks fun. Perry |
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| niall1 Senior Member Joined: 20/11/2008 Location: IrelandPosts: 331 |
just a final thought Bob.. with a commercial mill (product) getting a known power/windspeed logging system would be a good thing...it,ll graph up everything nicely W kwh Power/Wind time etc.. a commercial one will come fully calibrated ....the stats will speak for themselves this,ll free up your time for other things... theres lots of info on the site/web about logging wind and output ...using one on a mill is a real eye opener , the info is there right before your eyes , thats something people really want to see...(from a commercial supplier) i dont envy anyone who makes a product and sells it on to someone else...i thought about making some standard wood props a while back i abandoned the idea later.....just to many risks for my liking with windmill blades.. niall |
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| BobMann Senior Member Joined: 30/06/2011 Location: United StatesPosts: 134 |
Here are some new spec on my Mann Made turbine Steve has done the math and helped out a lot. Bob Mann Okay, here are the results on the Smart Drive (The Mann Smart drive with the stronger magnets and the machined rotor.) These powers are calculated, but they are based on: 1) Bob's measurements of rectified Delta voltage vs RPM 2) My measurements of stator resitance vs current. I think the results should be pretty accurate, but nothing beats a real world power test. First Lets look at how this alt would work going into a 12v load. It's a high voltage alt (1v per RPM) so we'd expect it not to be very efficient. Pl is the power into the load, and Pst is the power wasted in the stator as heat. The turbine has to produce Pl+Pst at that RPM. 
And the chart shows that for high powers it is not very efficient. 
However it does have it's uses in this configuration. If you have a slow turbine that you want to get just a little power out of (20w or so), this is the alt for the job as shown in this chart with lower RPMs. I think 20 watts at less than 30 RPMs is impressive. 
Here are the same type of results going into 24v. With twice the voltage the power is better. 
Where this alt really shines is if you have a high voltage MPPT. These charts show the power vs RPM and voltage vs RPM. As I mentioned in an earlier post, this alt has the ability to heat and even destroy itself. So any load put on this alt should be smart enough not to let it produce too much current or it will melt down. I'd guess the limit is around 7 amps in delta or about 600 watts in the stator. This limit is the reason the voltage curve changes slope. Even though you could pull more power from the alt at those RPMs, I think it would melt down if you did. Still there is lots of power and it's not really much of a limitation. 
-- Edited by sjh7132 on Wednesday 17th of August 2011 10:39:57 PM -- Edited by sjh7132 on Wednesday 17th of August 2011 10:40:55 PM |
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