Author Topic: My first project (Read 4781 times)

SmoggyTurnip · « **on:** December 13, 2005, 08:14:39 PM »

Hello everyone, I live in Prince Edward Island, Canada. I have been reading the board for quite some time now and searching the net for info on building wind turbines. I have decided to take the plunge and give it a try. Here on the Island there is a wind test site used for testing commercial wind mills and they have collected data on the wind speeds every 10 minutes for the past 6 years. They were kind enough to give me the data and I made the following chart to help me in my design plans. The data is for 6 months starting on October 1 and ending on March 31 for last year. The x axis is the wind speed in mph and the y axis is the number of minutes that the wind was at that speed or higher. So for example the the first column is 262800 minutes because the wind was 0 mph or higher for the whole 6 monts.

Each colum is 1 mph so the graph goes from 0 to 50 mph.

Also note that the wind speed was at a height of 30 meters. The goverment on PEI sponsered a project where a 3D computer model of landscape of the island was created from satellite data and used to predict the wind speed at any other part of the island to a resolution of 30 meters. I turns out that in my area the wind speed is pretty much the same as it is at the test site.

What I want to do is build a turbine that will assist in heating my home during the period that is shown on the chart. I have 60 Neo magnets 1" X 2" X 1/2". I have no design yet.

This diary is intended to be a documentary on the whole process from design to completion.

I will try to keep this diary up to date so that you all can gain from the many mistakes that I am about to make. And I hope if you see them comming before I do you will let me know.

This project seems to be a little different than most turbine projects described on here because it does not involve charging batteries. If you know of any stories on the board that involve this type of project please let me know.

Any comments would be greatly appricieated.

Smoggy

SmoggyTurnip · « **Reply #1 on:** December 13, 2005, 02:30:47 PM »

This is a picture of the bearing I plan to use for my mill. I am not sure if it is big enough. How can one tell. I am thinking along the lines of a 17' dai mill aprox 3-4 kw.

willib · « **Reply #2 on:** December 13, 2005, 07:22:08 PM »

i suggest you should download this program .

http://www.emachineshop.com/download/index.htm

then you can try out different scenarios as i have.

electrondady1 · « **Reply #3 on:** December 14, 2005, 07:53:39 AM »

dear Mr.turnip

if you plan on posting a lot of photos ,

please reduce there size.

ive got an xp op.system, all you need to do

is click file , "resize picture" and it will make a smaller copy

i live in ontario, very interested in a heat generation system as well

good luck

SmoggyTurnip · « **Reply #4 on:** December 14, 2005, 10:26:02 AM »

Yes you are right about the picture size. I am new at this so it will take some time to get these posting details down. Is it possible for me to edit the above posts and use the smaller versions of the pictures I made?

TomW · « **Reply #5 on:** December 14, 2005, 10:32:50 AM »

Turnip;

Sure is.

Just delete the originals and upload your resized files with exactly the same filename. Case matters on filenames too.

Cheers.

TomW

SmoggyTurnip · « **Reply #6 on:** December 14, 2005, 11:06:18 AM »

Thanks Tom - it seems to have worked.

Waterfront · « **Reply #7 on:** December 14, 2005, 11:34:22 AM »

Nice! I live in NB, Canada, and I'm planning to try out a first «big» project too. It's to bad you didn't get 64 magnets, you could have made 32 mags per rotor, and had a nice 3 phase system (with 24 coils).

What kind of configuration were you planning with your 60 magnets?? 28/21 with a few spares if you accidentally let a few of them snap together and they break? (Happened to me, I saw sparks, but thankfully they didn't break...)

Keep posting on your progress!

SmoggyTurnip · « **Reply #8 on:** December 14, 2005, 12:41:27 PM »

I haven't decided yet. I think I will put 28 magnets on 2 disks and experiment with some different coil arrangements and go from there. I was thinking along the lines of Hugh Piggots Nirvana machine but I am kind of worried that I can't find any info on the end result of that machine.

coldspot · « **Reply #9 on:** December 14, 2005, 10:26:04 PM »

"build a turbine that will assist in heating my home"

I also will be very interested in watching this happen. Good Luck!!!

But, I don't follow how you intend on doing this- just running heat "DumpLoads"

with the power generated??

electrondady1 · « **Reply #10 on:** December 15, 2005, 08:34:41 AM »

smoggy , thanks for the photo reduction.

it sounds as though you want the same thing as my self . that is ,

when the wind blows your geni kicks in and powers up sone heaters.

no batteries involved!

here's what i've figured out so far;

the stator coils supposedly release as much heat from resistance as what they make in electricity.

ac travels better than dc

resistive heaters don't care if it's ac or dc

watts is watts the heaters don't care much about volts and amps

windmills don't like to start under load

some sort of voltage sensitive device is required to limit the initial load seen by the genni and to allow it to get up to speed.also to feed in more load gradualy.

the nature of this device eludes me but i continue my search.

Flux · « **Reply #11 on:** December 15, 2005, 08:54:41 AM »

One or two points that need clearing up.

For a heating generator you certainly don't want to dissipate half your watts in the stator, keep the efficiency as high as possible or you will be limited by stator burn out. This does probably need a bigger generator but it is also a case of proper load matching.

Heaters do care about volts and amps. The voltage you apply will determine the watts you get from the heater. You can under run them, but if you exceed their voltage rating they will not last long.

You are right about needing a device to switch the load in when there is enough wind to power the generator and with simple switching control you will need to add heaters as the wind speed rises.

AC is much easier to switch, but DC is easier to keep a balanced load on the generator but you will most likely need electronic switching or very expensive DC contactors.

Unless you can use pwm with mosfets or Igbt's you would be wise to stick to AC.

Flux

electrondady1 · « **Reply #12 on:** December 15, 2005, 11:28:54 AM »

flux, thanks very much for your insight.

"keep the efficiency as high as possible"

ok, my understanding to date, an "efficient" genni, would have low internal resistance. ether through the use of large conductors or better, through the use of multiple small conductors avoiding eddy currents.

"if you exceed their voltage rating they will not last long."

ok the heaters i have in mind (base board type) are normaly rated at 220vac and according to code are fused with a 30 amp breaker.they can be used with 120vac but produce less btu's .

in my dreams i can build a genni capable of such output. well maybe if i get sixty big neo's like smoggy!

"you would be wise to stick to AC."

unless it was plug and play,no contest, my understanding of solid state circuits is zero.

here is what i was thinking would be required.

a small load on the genni that would not impede start up but provide a current to flow. this current would then trigger a solenoid (or perhaps a series of solenoids) closing a circuit to a heater.the term cascadeing comes to mind.

i have been thinking if the geni output was rectified to dc, something like an old style voltage regulator could be adapted to serve the purpose. i have been google searching the archives but have had no luck .

farmerfrank · « **Reply #13 on:** December 15, 2005, 11:36:29 AM »

Most heaters have too much resistance to get much heat from them at low voltage. Connecting a heater directly to a genny will stall it due to the fact of constant load. Some sort of regulator and a battery is required to get the turbine up to speed without load. DC actually has less losses than AC due to hysteresis. Large windmills that are offshore use DC to bring the power to land for this reason.

The power goes up with the square of the voltage. I have tried all this.

SmoggyTurnip · « **Reply #14 on:** December 15, 2005, 11:48:00 AM »

I am not sure if I agree with this. Let's say I built a generator that can produce an output of 2K at 20mph wind. Lets say It is running at 80% efficiency. Supose further that it cost me $2000. Now I am sitting in my house on a cold winter day looking out the window admiring my accomplishment and thinking to myself "I just built a wind powered heater for $2 per kilowatt). But then I continue thinking and I say to myself I wish I had more heat in here. Maybe I should have spent more money and build a bigger generator. hmm, if I just go adjust the heater so that its resistance is closer to the internal resistance of the generator I will get more heat in here and it won't cost me any more money, as long as I don't burn out my stator. But my generator will be less efficient - ah who cares I will do it anyway.

So it seems to me that what ever size generator I build if it is really efficient I will always want to run it less efficient because I will get more heat for no extra cost.

Of course you have allot more experience in this stuff so please help me find the flaw in my reasoning.

SmoggyTurnip · « **Reply #15 on:** December 15, 2005, 02:57:51 PM »

Below is a diagram of the rough idea of the generator I am thinking about. Much the same as most dual rotor systems that I have seen on here. I am a bit foggy on the details of the attachment of the blades. I have not seen a good picture showing the details of the attachment. What I have drawn is what I assume is done but I am concerned that if this is the way the blades are attached that a small amount of flex in the blades would cause the front rotor to bend and crash the magnets into the stator. Any comments or advice would be welcome.

Thanks in advance,

Smoggy.

Waterfront · « **Reply #16 on:** December 15, 2005, 03:46:59 PM »

Yeah, I saw your posting asking what happened to the Nirvana machine. I haven't seen any other info about it either, maybe Hugh just put the project aside. If it's flying sucessfully, it would certainly be a good starting point, as far as prop measurement and angles, along with some good ideas on the tail and just general construction tips...

farmerfrank · « **Reply #17 on:** December 15, 2005, 04:13:44 PM »

Oh I wish it was all that simple and cheap. I am afraid that without a battery system of sorts and an inverter things wont exactly work as planned. Reducing the resistance to get more heat works in theory but not so good in practice. Let me know how you make out!

farmerfrank · « **Reply #18 on:** December 16, 2005, 06:42:53 AM »

Where in Ontario? I am in the Chatham area. Hello neighbour

Gary D · « **Reply #19 on:** December 16, 2005, 07:37:06 AM »

It's Greek to me, but Hugh Piggott(sp?) has a circuit that does heating without batteries. The nervana (sp?) project I think was designed for this exact reason (Space heating). As with all info. on the otherpower site, build at your own risk (personal responsibity rules here!) The info. below the circuit on the link page could also be interesting. Link below... Gary D.

http://www.scoraigwind.com/circuits/

Gary D · « **Reply #20 on:** December 16, 2005, 07:53:35 AM »

Not noted by me was the fact that this circuit was probably designed for a specific size machine. The frequencies (hertz?) would be much lower for a larger machine as would the need to dissipate more watts.... but the circuit could be revised(changed values?) for differing voltages and amps by an electrical Guru...Gary D

electrondady1 · « **Reply #21 on:** December 16, 2005, 08:25:33 AM »

farmerfrank, i just noticed this post, i live in wasaga beach . i've been to chatham, i nice town.

SmoggyTurnip · « **Reply #22 on:** January 27, 2006, 10:19:13 AM »

Here are some pictures of my new rotors, stator mounting bracket and bearing. The rotors are 20" diameter and 1/2" thick. The Stator mounting bracket is 24" diameter and 1/4" thick. Both were waterjet cut and turned out real nice. The bearing is a 6 bolt trailer hub rated at 5000 pounds. I plan on attaching stainless sheet metal from the spokes of one rotor to the matching spoke of the opposing rotor to assist in air flow over the stator. I will also be covering the holes or one rotor with sheet metal for the same purpose - what do you think?

Sorry about the poor quality pics but I am no photographer. I also resized the pics twice but when I preview the post the pics still come up very large in size but at lower resolution. Am I doing something wrong here. How can put just a link in my post rather than the actual picture?

SmoggyTurnip · « **Reply #23 on:** January 27, 2006, 10:25:33 AM »

I posted my rotor pics and now when I open my diary all the pics are comming up larger than my screen - they were ok before. What's going on?

ghurd · « **Reply #24 on:** January 27, 2006, 10:33:11 AM »

You compressed the pixels just fine, but the dimentions need changed to 4x6" or 5x7" or whatever. At least they load fast!

SmoggyTurnip · « **Reply #25 on:** January 27, 2006, 10:43:06 AM »

But I saved them as 1 inch wide - and I don't understand how that could change the size of pics I posted weeks ago.

pyrocasto · « **Reply #26 on:** January 27, 2006, 11:14:00 AM »

There is code built into the board sizing the pics dependent on that user's screen. I'm on 1280x1024 so it blows them up for me, making them look a little pixelated.

SmoggyTurnip · « **Reply #27 on:** January 28, 2006, 01:58:34 PM »

I am now building my alternator I am thinking ahead to my blade design. I am planing on building 6 meter blades with tsr=5. Using the spread sheet calculator with Blade diameter = 6 meters, tsr=5, blades=3, angle of attack=5.5, coefficient of lift=8.5 and number of stations = 10 I get the following results:

Wood width at tip = .259 meters

Wood width at .9 meter radius = .696 meters.

Wow! this seems alot wider than I figured on. Can I reduce the width of these blades without a big power sacrifice?

ghurd · « **Reply #28 on:** January 28, 2006, 04:30:26 PM »

I'm no blade expert, but I think the TSR of 5 is causing part of the problem. Most guys try for about 6~7. Also, faster blades are usually better concerning the alternator design.

SmoggyTurnip · « **Reply #29 on:** February 02, 2006, 07:36:59 AM »

Using the spread sheet program with the following inputs:

Tsr = 7

Blade diameter = 5.5 meters

Number of blades = 3

Angle of attack = 5.5

Coefficient of lift = .85

I get the blade shown here:

And this is what it would look like on the tower:

These blades seem very thin to me. Do you think this is a realistic blade design? Would you trust them to be strong enough? Is there enough tower clearance? Should they be built using hardwood to increase stiffness? Any comments would be appricieated as I don't know anything about blade design.

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Author Topic: My first project (Read 4781 times)