Author Topic: More on 22 foot duel rotor (Read 3654 times)

harrie · « **on:** May 31, 2007, 12:05:31 AM »

The winch had no problem bringing it down, I think it will be ok, because of the worm gear reducer. I agree with dan, that the winch alone, is not really what you want for this application.You can also see how I beefed up the unguyed area, and added more guys, I now have 12 guys at the top of the tower, I think this will do the trick. I also think the counterweight system in the next picture I installed takes alot of strain off the winch.

I took the vertical tail I had off, and replaced it with a cylinder tail, made out of a fiberglass resin tank out of a water softerner. I was able to balance it to the turbine by placing sand in the tank. With the tapered roller bearings I have in the yaw system, I beleive the tail will still have enough surface to turn the turbine. this is pictured below.

The next picture shows the yaw motor, that engages by a cable that runs down the tower, and is powered with a 14/2 115 volt wire that also runs down the tower. It is a 2 RPM motor that is geared very low.

I had to put about three pounds of lead on the one blade to get it into balance as shown in the next picture

I thought I would show a different kind of cable clamp, that we used for rigging on construction projects, OSHA requires this type when they are supporting people in their work area.

Ok, I need some help from you guys that are up on electric problems. When I had the mill up, at 15 amps, it started to make a terriable loud noise, like it would if you thru the short switch at high RPM. than, it would quiet down at 20 amps and made no noise at all up to as high as I let it go which was 40 amps. I also while putting the mill together, before the blades were on, wired it to my battery bank and spun the rotors as fast as I could by hand, and noticed a noise comming from it like sticking a wire into the spokes on a spinning bycicle wheel. I than checked my battery bank, and discovered I had not closed the knife switch on the battery bank ground. I closed it, and the noise went away. Is this a normal condition, The only other thing i can think of is my rotors are not running as true as I would have liked them to be.the run out may be as much as 1/16 inch. would this effect the frequancy and cause viberation??? Thanks in advance.

jmk · « **Reply #1 on:** May 30, 2007, 07:03:10 PM »

It looks like you drilled holes at the root of the blade to put in lead for weight? I hope they aren't to deep or that blade will break. A definite weak spot there. You need the root to be strong. If it breaks it is going to break there. I had a problem with mine. A couple of months after I put it up I had to rebalance it. I had to take weight off the side I had put it on the first time and put it on the other side. Well, I am sure you know what your doing Harrie. I just thought I would add my two cents. I need to do that bracing method to my tower too. That's some wind farm you got going. I wish I had a better spot for a larger turbine.

dastardlydan · « **Reply #2 on:** May 30, 2007, 07:37:32 PM »

On my new Genny it's only a 10 footer,

that makes a lot of Amps.

When the volts and amps get to be the same it

make a odd noise, this happens at 14 volts and 14 amps,

as soon as the amps go up it gose away.

It sound like a growl or whine.

I kinda like it

You can tell when it starts charging.

++++++++++++++++++++++++++++++

jmk · « **Reply #3 on:** May 30, 2007, 07:51:32 PM »

My grawl gets louder as the amps get higher. Herrie's description sounds different than a grawl. Something has got to be rubbing. Does the click equal the amount of slots in the rotor in one rpm?

harrie · « **Reply #4 on:** May 30, 2007, 08:00:30 PM »

No, it is definatly electrical, I have a full 1/8 gap between each rotor and the stator, so nothing is rubbing. The click heard when I was turning by hand, was erratic, not steady. As far as the drilled in weight, they are 1 inch deep and the blade is three inchs deep. I have always did it this way, and have not had a problem. they are epoxed in, and fit very tight!!

Flux · « **Reply #5 on:** May 31, 2007, 01:36:15 AM »

Not sure about the noise, especially the noise on no load, there shouldn't be any under those conditions.

Noise on load will almost certainly be a resonance of something at that frequency and if it is bad enough may indicate serious vibration that may leave to failure in the long term.

Most alternators growl (probably at the six pulse rectifier frequency in most cases) but it is a modest noise and most is transmitted down the tower. Some noise may be audible directly but it shouldn't be much to worry about. If this is a terrific noise as you say then it needs investigating. When you get to these large size machines there are large forces present and if something is not rigid enough and you hit resonance the vibration could be considerable.

Most likely area is the stator or stator mounts but I suppose "bell mode vibration " of the magnet discs can't be ruled out.

If you can measure the frequency of the noise and relate it to the alternator frequency then you will have a better idea where to look.

Flux

tecker · « **Reply #6 on:** May 31, 2007, 04:29:03 AM »

I think your listening to the load balancing . It's hard to get a perfect alignment . Even if you got perfect geometry you might still git kick backs as the rectifiers blend. Multiphase stators with Air cores barks back in that way (even grid stators with metal cores buzz back with unbalanced load s ) .You might Scope the three phases and look for differences. It sounds like back emf builds faster in some of the phases and your listening to harmonics until the inertia builds and the stator conduction equalizes between phases .

tecker · « **Reply #7 on:** May 31, 2007, 04:37:22 AM »

The low speed tick sounds machanical You got one heavy blade there. That's a big unit and a very nice build .

harrie · « **Reply #8 on:** May 31, 2007, 09:43:25 AM »

thanks for the repley Flux, The noise I heard spining by hand, was with the wires connected down thru the tower, and into the bank. the positive was connected to the bank, but the negative was not. Of course this was going thu the rectifiers. I thought maybe because the negative wasent connected to the bank, I was getting some kind of a jump to natural ground out of the stator???. There is no noise at all when the wires are not hooked into the bank. Also, I notice the anolog meter I have measureing the AC volts, bounces alot on the way up to 48 volts. I think that is normal, but not sure.

I have no way of measureing fequency, and have no wave monitor. And yes, it is a very loud noise, no noise up to 15 amps, and quiet after 20 amps?? Im going to try and put some rubber hose or something on the stator brackets and see if that helps?

Flux · « **Reply #9 on:** May 31, 2007, 11:43:18 AM »

"Also, I notice the anolog meter I have measureing the AC volts, bounces alot on the way up to 48 volts. I think that is normal, but not sure."

That doesn't seem normal to me. With those large blades there is almost certainly no chance of instantaneous changes in voltage.

There should be no difference on open circuit with the rectifier connected or not as long as the battery is disconnected. If you have something breaking down in the cables stator or rectifier it could lead to trouble.

Flux

TomW · « **Reply #10 on:** May 31, 2007, 12:49:05 PM »

flux;

There should be no difference on open circuit with the rectifier connected or not as long as the battery is disconnected. If you have something breaking down in the cables stator or rectifier it could lead to trouble.

I tend to agree here. the symptom certainly would be consistent with that type of failure. Something reaches breakover voltage on it and shorts across for a millisecond or two and repeats.

All of the dual rotor units I have observed [not a great many] have a characteristic growl when charging that is not there with no load. It is not very loud and usually mostly heard near the tower.

My other thought was a loose or insufficiently solidly mounted stator jumping around under load or in reaction to the induced fields.

I would be suspicious of that jumping meter reading myself as it seems unusual.

I hope he figures it out before it causes other trouble.

Don't you love remote troubleshooting.

Cheers.

TomW

outback · « **Reply #11 on:** May 31, 2007, 04:50:38 PM »

Dandy machine there i really like your prop but i hate to be you when the wifey discovers something missing in the kitchen! the last time i had a noise like that i discovered a broken weld on one of my stator mounts.it made a funny noise only at certain times i guess because of certain vibration at certain speeds.fine looking work and let us in on it when you figure it out.

harrie · « **Reply #12 on:** May 31, 2007, 08:45:50 PM »

Maybe that is the problem, The AC is taken off ahead of the rectifiers from only two wires, and the battery bank is connected after the rectifiers?

Anyway, we had a calm day, and she is now up, but being calm I dont know nothing yet, but will let you know what happens.

Thank you all for the help!!

harrie · « **Reply #13 on:** June 01, 2007, 03:01:27 PM »

Hi, yes, I think your right. It is up now, and we have aabout a 10 mile wind, and It still makes a little viberation noise at 13 amps, but no where near the noise it made before. I dont know if the rubber I put on the stator bracket helped, or taking the sheet metal tail off.

It is performing just the way I want it, its been doing between 5 and 20 amps all day at from 60 to 75 RPM.

The unguyed section at the top, now is very ridged.

The yaw motor works great also, I can turn it into the wind, and keep it locked in. no more swinging back and forth with turbulance.

Thanks again, Harrie

johnnythefox · « **Reply #14 on:** June 02, 2007, 08:20:22 AM »

Hi Harrie

I was thinking on your noise you were talking about and believe it maybe the circulating current in the coils with the blade switch open I would think it would be very loud.

Please keep an eye on that blade you added all the weight to that's (the) week point,there is a reason is called the root,better to add the weight in the length of the blade in the thick part.

This is important enough to advise you to start construction on a new blade now, better too error on the side of caution than to rebuild the whole thing if it fails. Nuf said

All things considered this is a very impressive project.

Good work

Good luck

Johnnythefox

harrie · « **Reply #15 on:** June 02, 2007, 10:08:47 AM »

No, I totaly disagree on the saying I have weakend the blade, that is the thick part of the blade, and if anything to epoxy a diffent substance into it, will make it stronger! IM not worried!

ghurd · « **Reply #16 on:** June 02, 2007, 03:50:31 PM »

I am not sure where this fits, so I will put it here.

Muzzle loader builders often pour molten lead into holes in the stock.

It works, and the wood has not caught on fire or scorched for me.

Often at the front of the stock, sometimes other places too.

Sometimes wet heavy paper grocery bags are used to hold the molten lead back.

I would pour the lead into a hole (with a larger bottom than opening) rather than trust epoxy to broken wood fibers.

Maybe that's just me.

G-

PS- When do plan on building a "Full Sized" windmill?

Dang, that thing is a monster!

harrie · « **Reply #17 on:** June 02, 2007, 08:32:06 PM »

Yes, I have saw this done also, and yes I thought about pouring the lead in, but the hole was so close tollarance that I coated the entire hole with the epoxy, and than had to pound the lead in. I poured them in peices of copper tubing first.

Ghurd, I beleive this is the last one I will build, I remember when I first came to this site, and during a converstation with DanB, he said that bigger is not neccesarly better, but guess Im stuborn. Ha. I have also did a couple of 3 phase motor rewinds, ( thanks to Zubbys great site.) I have them driven by gas motors to charge my two banks if it is needed.

I think I now want to work on a elect bike, or maybe even a small car. I hate these gas prices.

Thanks for the repley. Harrie

jimjjnn · « **Reply #18 on:** June 02, 2007, 10:15:47 PM »

Harrie,

With your stubborness and persistence going for you, you managed to do a lot of things. Successful or failure, you persisted. I hope you will still be here as your projects are always good reads and much fun.I am unable to do these things due to age and the fact I live in a condo where rules keep me from having the fun that all of you on this board are having.

I can only applaud you for your persistence and stubborness. You have succeeded

Stay on the board and keep us aprised of your new projects.

Keep having fun.

harrie · « **Reply #19 on:** June 03, 2007, 08:52:41 PM »

Thanks Jim, Ya, I know what you mean about getting old, Im 65 now and sometimes wonder if I should keep doing the things I do, but I guess ya cant sit around and wait to die, so what the heck, gota keep busy. Im sure I will stay around this site, the guys and gals here have sure helped me out with the electronics. Thanks again for the kind words. Harrie

jimjjnn · « **Reply #20 on:** June 04, 2007, 12:10:01 AM »

72 here in a couple of months so I have a couple of hours on you. :-))

elvin1949 · « **Reply #21 on:** June 04, 2007, 05:30:43 AM »

It ain't time that get's you down.

It is the mileage.

later

Elvin

phil b · « **Reply #22 on:** June 04, 2007, 03:38:56 PM »

harrie,

several of my older mills had a big growl. I took them down several times looking for something wrong. I thought it might be the vibration of the stator. I noticed it seemed to be related to RPM and the state of the battery charge. I just left them alone and accepted it. My newest has a slight growl at low RPM.

News:

Author Topic: More on 22 foot duel rotor (Read 3654 times)