Author Topic: 26 foot progress (Read 3353 times)

harrie · « **on:** September 19, 2006, 02:34:49 AM »

I was surprised to see how the 48 volt cut in was at 48 RPM rectified, but I think Im happy with that. The air space is now 15/16" wide. Rotors are 24 & 3/4" dia, 24 2" by 1/2" rnd mags N38 each rotor and 18 coils two in hand #15 wire with 75 turns. First picture, is of the yaw bearings, I wanted something that would turn very easy in very light winds, and this did the trick. you can see the top bearing, and there is enother one like it at the bottom of the 16" section of 4" pipe.

This is a low RPM, high torque 12 volt motor that will have a cable running down the outside of the tower along with the power cable for the motor. The cable will engage the gears and will turn the turbine out of high wind, and lock it in place, or at least give me a chance to short out the geny at a low RPM. Im doing this because I will have no furl. I live in a low wind area, and am counting on the turbine going into stall before it runs wild. I guess we will see!

This shows a small sleeve that will alow the back end of the hub to slide inside to help keep water out of the rear bearing.

This is a hub from a 1996 ford two wheel drive that has had the rotor machined off, leaving the flange, and also machined to accept the two rotors at close tollerance. also in the picture is the outer flange and shims used to set air gap.

Rotors poured with vinyl ester with sheetrock texture added.

30" stator with back rotor on. one can see how the mags line up in phase, and out of phase.

This shows the front flange in place, and ready for the front rotor.

Front rotor in place, with 5/8" by 7" thru bolts in place, along with the jack screws.

view of back side, showing stator supports. I was able to use 3 & 1/2 by 5/8" stainless steel bolts to mount stator, I welded the heads to the bracket, and have enough threads to set stator.

Now to find cedar for the blades, lots of fun.

Shadow · « **Reply #1 on:** September 18, 2006, 09:23:26 PM »

Wow! Harry, They just get nicer and nicer every one you do! Any specific reason for using round magnets? I did the same thing with mine, used prefit shims for air gap, now I just put it together and tighten the bolts. Only adjustment I have is moving the stator in or out to get equal distance from both rotors. Again very impressive professional work!

harrie · « **Reply #2 on:** September 18, 2006, 09:51:20 PM »

Hi Shadow, Yes, Im not to hep on hanging all that weight on allthread, and only one nut to worry about and that is to hold the blades on. The shims work out good too, no movemnt. The mags, I guess ive had good luck with, so keep using them. Also the price is right, and I get good results. Thanks for the comment.

willib · « **Reply #3 on:** September 19, 2006, 02:02:01 AM »

Awesome Harrie !

very professional looking

Titantornado · « **Reply #4 on:** September 19, 2006, 03:24:13 PM »

WHOA!! I can't wait to see the blades for that monster!

I'd like to see an automatic furling mechinism, but I'm sure you know what your doing.

Nicely done!

jimjjnn · « **Reply #5 on:** September 19, 2006, 07:01:57 PM »

What kind of bridge rectifier or diodes are you going to use? Going to be a lot of amps going out of that monster

harrie · « **Reply #6 on:** September 19, 2006, 07:57:17 PM »

Well its 48 volt, so hopefully it will go into stall before the amps go too high, at least this is what Im trying to do, keep cut in low enough to stall it. I plan on using just three 50 amp full wave rectifiers. As DanB said I may have to lower the blade dia. some, we will see.

harrie · « **Reply #7 on:** September 19, 2006, 08:03:46 PM »

Hi Rod, well, Im not sure I know what Im doing, and I wish I was smart enough in electronics to make it a automatic furl, which I think would work, but for now it will be only accomplished hands on. I sometimes just get a crazy idea, and go for it. ha.Thanks for the repley.

makenzie71 · « **Reply #8 on:** September 19, 2006, 08:43:41 PM »

Harry, if you don't want to build one simply due to inexperience, then buy one. You can buy the furling tails from any place that sells windmills. They're not cheap, but the quality of a proven, mass-production piece is unbeatable. Hit me up if you don't know who to call.

harrie · « **Reply #9 on:** September 19, 2006, 10:16:48 PM »

Now what kind of furling tail are you talking about, I have built tilt back furling, and the offset swing tail that is common on this site. If your talking a device to measure the speed of the wind, and electronicly turn it out of the wind at a set velosity, than I would be interested. I have a 12 foot dia. , and a 18 foot dia. flying now, and both have tilt back furling, but rarely do we have wind that need furling. Only time that happens is in a occasional storm, when I usualy shut them both down and disconect the line to the battery banks in the event of lighting.

makenzie71 · « **Reply #10 on:** September 19, 2006, 10:36:57 PM »

no what I'm talking about are purely mechanical...similar to the the offset tails on this site but they work directly behind.

DanG · « **Reply #11 on:** September 20, 2006, 07:15:08 AM »

Not to be standoff-ish, looks like 100% forever build so far, but.. . gangly 13' blades woofering in turbulence, is it gapped enough from the mast? What angle set-back is the shaft from level and what type & size lumber, er, timbers will you be using to carve blades from? Good work & thanks in advance!

DanB · « **Reply #12 on:** September 20, 2006, 08:02:30 AM »

Nice work. I wonder if you have an idea about the resistance of the stator. If not I think you could get in the ball park if you have an idea about the total weight of copper you used.

To me it seems your cutin speed is in the ballpark (if not a bit slow) but I cannot imagine that the alternator will be powerful enough to hold back 26' blades - it seems like the resistance in this will be too high to be very efficient above perhaps 2KW. I expect it's going to be a good bit higher than it is in my 17' machine (Which just burned out again this weekend). I worry about the blades running away and heat in the stator... time will tell though! Those are just my thoughts on it - otherwise, it's very neat!

Flux · « **Reply #13 on:** September 20, 2006, 08:36:10 AM »

I have to agree with DanB.

I don't see any prospect of holding this in stall with 26ft blades. It looks as though it will run up through the range at tsr6 and will be on the top of the power curve. At 20mph your stator will be loosing about 2kW. If you never have winds in excess of 20 mph it may be ok.

If you want to hold it in stall then I think about 20ft blades is nearer the mark.

Nice work as usual. you know your wind conditions better than I do.

Flux

harrie · « **Reply #14 on:** September 20, 2006, 04:43:41 PM »

Not sure what you mean by gapped enough for the mast, If you mean the blades far enough away from the tower, than yes, it will have 16 inches. the shaft is 90 degrees to the tower. I plan on using western cedar if I can find it. Ill be laminating up 3 inch thick by 15 or 16 inches wide. thanks for the comment.

harrie · « **Reply #15 on:** September 20, 2006, 05:16:42 PM »

Hi Dan, I appriciate you comments, I know you have the first hand information on the ones you have built. The stator weights 32Lbs, so Im guessing the copper would be about 26 lbs subtracting the resin? I havent checked the resistance yet,so dont know. I will probley end up down sizing the blades like you said, but I still think its better to make them alittle long, cause you can always cut them off. If they are too short, you need to make another set. Sorry about your 17 going bad again. I just know this is alot of fun for me, being retired and able to learn something new.

harrie · « **Reply #16 on:** September 20, 2006, 05:22:49 PM »

Wow, 2kw loss. I hope that never happens. You think 20 foot huh? I really wouldnt want to cut 3 feet off each blade, maybe pick a happpy medium and start out with 23 foot. Im alittle stuborn, but I know you guys know what your talking about. Ha. Thanks for the comment Flux

Marco · « **Reply #17 on:** September 21, 2006, 12:37:57 AM »

I've used red western seeder for some outdoor garden furniture, where in scotland it is blasted by the most horrible wet damp weather and the wood holds up well.

Is a 13ft blade not coming close to the limits of a wooden prop?

Marco.

Flux · « **Reply #18 on:** September 21, 2006, 01:52:43 AM »

If you have already made the blades then by all means try them at 26ft, but make absolutely sure that you can shut it down with the slew motor. I doubt that shorting the alternator will stop it in a high wind with 26 ft blades.

If you haven't made them yet then starting at 23 ft would be better. If you have to cut them down a lot you have to reduce the width and tip angle to keep the tsr somewhere near right.

With no furling system you will need to be very careful until you know its capabilities. By all means go for the best low wind results as long as you can control it.

Flux

paradigmdesign · « **Reply #19 on:** September 21, 2006, 06:46:49 AM »

In a few months I should have some 11 foot comopsite blades ready for testing, if you are interested, and willing to wait till then.

What kind of clearence are the blades going to have from the tower. I can't tell the angle it is mounted from your pics.

harrie · « **Reply #20 on:** September 21, 2006, 08:29:13 AM »

Hi, I have 16 inches from the tower and have the shaft 90 degrees to the tower. should be plenty of room

Countryboy · « **Reply #21 on:** September 21, 2006, 12:42:33 PM »

Harrie,

Read the latest Monday thread. An interesting idea was mentioned which would eliminate cutting blades down, and running the risk of cutting them shorter than necessary.

Use thick tape on the leading edges of the blades. This disrupts the airflow enough that it lessens output. You may want to make the 26 foot blades, cover the last 3 feet on each blade with the tape, so they act like 20 foot blades. If all goes well and you feel you can get away with a bigger blade, remove some tape until your blades safely perform the way you like.

Once you have the blades matched to the machine, the amount of length of tape left on the blades will tell you how much you need to cut down each blade.

paradigmdesign · « **Reply #22 on:** September 21, 2006, 01:58:10 PM »

I belive there is some company in Africa that has built like 70 foot wooden blades. I will see if I can find the link.

harrie · « **Reply #23 on:** September 21, 2006, 07:35:51 PM »

now that might be worth a try, I just know that on my 18 foot that has been flying now sence may, has never been close to a overspeed condition, its in 12 volt, 16 inch rotors with 12 coils 2 in hand #15, with 60 turns. It is always in stall at around 40 RPM. Yes the amps are low, from 2 to 7, but I never have to worry about it, and it keeps the batterys charged and almost always has the dump load lit up thru my C-40. Thats what I hope do do with this big one only in 48 volt. Again tho, Im not off grid, and only use it for some things and for backup. Lots of fun, thanks for the advice. Harrie

jlt · « **Reply #24 on:** September 23, 2006, 05:29:35 AM »

that,s a good looking wind turbine you are building. i also live in a low wind area. but i still get storm fronts that come through. with 50 to 60mph gusts.i have lost more than 1 to them.it always happens when i,m not at home.with that much effort you have put into yours .it would br good insurance to have a folding tail maybe with the gear moter that you allready have. anyway thats just my thoughts.hope yours lives a long and heathy life.

pepa · « **Reply #25 on:** September 25, 2006, 11:00:21 AM »

hi harrie, you have made a beautiful machine. it seems that you and danb have the same problem that most of us have with these larger machines, keeping them safe when no one is around to watch over their operation during high wind times. my largest winmill to date is a 17ft. danb copy that works great with no problems so far, i built a automatic cutoff switch that was controlled by the speed of my anemometer. after some negitive feedback from some of the board members, i stopped using it as a kill switch until something safer is developed. i like your geared motor for furling, but not the idea of no machanical furling. i am sure that some of the electrical people on the board can show you a way to have the motor activited by some type of electric relay to make it automatic. i like flux's idea of a heated oil activated switch in his reply to danb. building for fun is a lot more fun than building for the need for power (have to have), pepa.

Eurapart · « **Reply #26 on:** November 07, 2006, 08:21:17 AM »

Very very impressive! The lines are smooth and the design great! Looks sturdy enough.You are truly a gifted individual! Cedar blades are best? Any tips for a beginner?

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Author Topic: 26 foot progress (Read 3353 times)