wind generator query

[23skadoo]

I have a Greenpower 24V 200W wind generator and control box. I am replacing the controller with a Oatley kit K241 as the original unit is badly designed. I am interested in any feedback other owners of these units will be able to offer. The blades are fairly noisy in operation, and I was wondering if rounding the blade tips would reduce this(they are cut square)Also to reach 24V the unit seems to be spinning very fast, is there a way to use more of the low speed energy.

[jimovonz]

Do you have a link or specs for the 'Greenpower 24V 200W wind generator'? I have seen a number of the same cheap Chineese turbines go by different names.

[nothing to lose]

In building PVC blades I have found two things that often quit blades but does not effect their work.

Round the tips. This helps to quit them compared to a square tip blade. Rounded edges seem to work as well or better and certainly more quite with what I make anyway.

Also thinning the tips. That is to say that if they are 1/4-1/2 thick now, sand them down on the last inch or so to taper them to be as thin as you can at the final tip egdge. A drastic drop from 1/2" to 1/8" is not good, it should be a smooth taper as needed for as long as needed. 1/16" right at the tip should be good. Do not weaken the blade though while doing this tapper. Last Inch or 3 should be enough to acheive this and it should be smooth not a sudden drop.

Rather it helps on your blades I can't really say, but it works well for PVC and such blades I been building myself.

Also a rounded leading edge helps to cut the wind, and a thin taper on the trailing edge helps to avoid drag as the air at front and rear re-combine together as the blade passes. That trailing edge tapper may also help reduced noise.

[Jerry]

Hi NTL.

I've tryed the rounding at the tips and you are quite correct. It reduces noise alot. It also seems to smooth things out a bunch and the blades spin abit faster.

I'm getting closer on finishing my first set of PVC pipe blades. I'm hopeing to cut the wooden hub out tommorow?

I'll post a few pictures when the blades are ready. I'm building two 4ft tip to tip sets.

One is useing the 6" diameter 1/16" thin wall pipe. The other is useing the 6" diameter 5/16" wall foam filled pipe. I'm building a triangle shaped wooding hub for these.

PS NTL could you e-mail me a note, some one needs some of your curved NEOs. I liked to put him in touch with you.

Thanks.

                               JK TAS Jerry

[nothing to lose]

wow Jerry that was fast.

I may have more #29 type arcs in a month, right now I'm out. I may have all the cash together to place the order next week. Been a rough year last year here. Lot's of outgo but little income.

Yes, I like the rounded tips alot, but thinning them as I mentioned also helps I think for both rotation speed and less noise too.

 At the tips not alot of strength is needed like at root or middle of blade, and thinning the tips seems to work nice. I take down the front side of the blade for thinning and leave the back as is for the curve.

I'm gonna try to post two ways I make my Pvc blades. With a handheld jigsaw works one way, with a bandsaw works another way. I get what I call A and B blades, both very good sets but not exactly equal if on the band saw. I spent allot of time typing up a text version the other day and was going to add pics later, but one wrong keystroke and it was all wipped out before it got posted.

[Jerry]

Hi NTL.

Care full with that spelling thing. I got in trouble for that.

                             JK TAS Jerry

[Turbulent]

G'day, I also have the same type of wind genny that you discribed and found it seemed to spin very fast before anything happened, I did some checks on the controler and found one of the rectifiers was faulty, unit was replaced under warranty but the replacement unit also had the same fault and same rectifier location.  I just replaced the rectifer pack with some heavy duty units myself in the end and also replaced the power cable that came with the unit ( as it is only power cord extention lead ) with cable 4 times the size and now it boots with some go getter amps with much slower spinning reqiured to start up charging, And yes I did work on the blade ends to deal with the noise problem.

 Been up 2 years now with no problems since so far so good for a cheap unit.

[TomW]

Jerry;

Care full with that spelling thing. I got in trouble for that.

Oh, that is funny, truly funny. I try to spell check everything [my computer does it on the fly].

I also try to say things clearly and precisely but a fair % of the readers on this board just read into it what they want.

Thats how I get into trouble.

As far as spelling goes, it has little to do with sharing information. I could go on, but I am already drawing a lot of fire lately and I can't dig up the energy to mix it up with a bunch of whiners who apparently can't understand properly spelled posts, either. Unlike them, I will not mention any names.

A favorite quote:

Mark Twain:

I don't give a damn for a man that can only spell a word one way.

Cheers.

TomW

[finnsawyer]

Damn it Tom, you have to get a thicker hyde.  Or is that hide?

[wayne]

I have a broken 12v 200W one with no blades and broken hub. The hard part is a shaft is bent too. Making a  straight shaft can do on my lathe but can't do taper. Like to find parts for this thing but seems a dead end road so far. Does anyone a parts guy.

Thks

Wayne

[jimjjnn]

Tom , Keep doing what you are doing, your way. Spelling? Who cares as long as I can understand the person.

I love Jerry's spelling (kidding). He is very informatime and his posts are always good.

There are many not using their own home language on this forum that use translation software that isn't up to par, but they are still readable. I can'y punctuate worth a damn but don't let it bother me. TOM, YOU ARE DOING A GREAT JOB !!!!!

[wayne]

[DanB]

I got Hugh Piggott's opinion on this once... it was something like 'lots of silly things get done to the tips of blades'.  I expect in some cases rounding them might quiet things down.  I think the biggest problem is that it runs fast - a high TSR and those sorts of machines tend to make noise.  I used to round the blade tips and find that it makes no difference in noise - square cut blade tips seem perfectly quiet to me, but I expect that's because the machines we make run at a lower TSR.

[nothing to lose]

Ya, my spelling gets pretty darned bad at times, allot of it is typos more than not knowing how to spell. If you saw some of my posts BEFORE I proof read them you would have a hard time reading them for sure.

Too bad the forum does not have a way to edit to correct a post once posted, I alsway spot more mistakes I made as soon as the "Thanks for Posting" pops up, but too late then. Simple spelling errors are not so bad, but when info should be corrected for a typo it would be nice to edit our own posts. No biggy.

"Mark Twain:

I don't give a damn for a man that can only spell a word one way."

I like that, and when in dought how to right a word, write it both ways, one might be correct and then people think the wrong one was a simple typo

Just don't waist bandwith cause band with is a terrible thing to waste.

Problem with spell checkers is that half the wrong stuff is correct! Waste, Waist, bandwith, band with, right, write, etc.. All spelled correct though half are wrong.

[23skadoo]

I have done a search on the Greenpower alternator ( sold by Jaycar Australia)but found no information. It is likely these Chinese units have been marketed under other names as well. The information on replacing the 4 core cable is a good idea and one I will persue. I have finished building the new controller box, gutted the old one and fitted the Jaycar kit unit. I would also like to fit a rope to the tail to disengage it without having to lower the mast, the only problem is the rope will have to pivot on the turbine outer and the travell down the inside of the mounting pole much like the output cable. I havent yet figured out how to get the rope entry to the mast with this unit. Anyway all good fun.

[23skadoo]

Thanks for your helpfull comments, the controller boxes must have had a lot of failures as I purchased 2 extras from another outlet(Oatley Electronics) for $10 each. They are a good source of parts and were sold for the heater load for another controller kit. I will look at the rectifier section and see if the others have the common fault. Tried to get a schematic from the sellers but they were not available.

[jimovonz]

I have imported a number of these same turbines direct from China. The controller is worth nothing (as a controller) so you have done well to replace it. 2/3 of the ones I have recieved are DOA and the other 1/3 are not far of dead. I have added rectifiers and my own shunt regulator. I have had good success modifying the blades to achieve both quiet running and better performance. The stock blades are distorted with flat piece under the leading edge where I presume it has sat while curing. I remove this flat to give a more appropriate shape to the aerofoil. The trailing edge is too bunt so I also sharpen this. This should make the blades substantially less noisy. I also round the tips and taper the blades over aproximately half their length (depending on diameter/model) and refrom the aerofoil. This gives a higer TSR blade that manages to eek out more from the woefully inadequate alternator. I have seen over 500w into a matched load from the 200w rated turbine without altering the furling point. This is the turbine that I have been using to develop my MPPT system.

EcoInnovation have information on modifying these turbines here: http://www.ecoinnovation.co.nz/links.php?code=8 (scroll down to the Wind section)

[23skadoo]

Thanks for your comments, I have saved the information and will modify my unit before re-installation.