Wind generator up again!

[tcmtech]

Well I am back at it after many months off from being able to play around with my wind power stuff. The weather warmed up this last week and was favorable enough to be able to work outside and up high without freezing or being blown a way.

This is my latest homemade wind generator that is once again made from old parts I had around the farm. The main frame is the same one I have been using for 9 years now but the blade and generator system that goes on it has been through a number of redesigns over the years.

This time I have set up with a 9.5 foot rotor, my biggest set yet so far, running on an old commercial inline gearbox that gives it a 16.5:1 speed increase from the rotor to the modified 28 volt 100 amp Leese Neville commercial alternator.

The gearbox is rated for around 8 - 10 HP at the speeds I will be running it at so its unlikely it will have problems. Plus I have full synthetic oil in it so it is not stiff at cold temps. The alternator is a modified Leese Neville 28 volt 100 amp unit that I changed the winding configurations from a double Delta 28 volt output to a single Wye output that gives me 100 volts at 28 amps so it basically just a reverse of the voltage and amperage numbers. This is also a heavy duty high duty cycle rated alternator so it will be able to run for long periods at the top of its output range without burning up.
This alternator is rated for full output at 3600 RPM or higher which in this aplication will be at a rotor speed of around 218 RPM which is about half what the actual blades are rated for. Given the overall system efficiencies the rotor will have to produce over 3 KW mechanical power at that 218 RPM to exceed the alternators minimum full output design capacity which should limit runaways in high winds this time hopefully.

I removed the stock regulator and am now just using a pair of 150 watt bulbs in parallel as a current limiter for the field coils. By doing so the two bulbs have a resistance of about 4 ohms cold and the rotor field coils are about 7 ohms cold which gives me a low speed self exciting ability but then limits the field power proportionally to the output afterward.
When hot the field coils are roughly 10 ohms and need 2.5 amps of current for full saturation. This works well being the alternator should top out at around 160 - 170 volts giving me a roughly 25 volt field voltage and a 140 - 150 voltage drop across the bulbs which are 130 volt rated.
The bulbs are 20K hour rated commercial bulbs that have heavy filaments and have shown that they can take far higher voltages for long periods of time without burnouts too. I tested one a while back at 170 volts for over an hour without it burning out.

Eventually I will have a SMPS that drives the field power at a constant 24 volts when ever the alternators output voltage is high enough but for now the light bulb shunt method will just have to do.

Now I am just waiting for some wind and hopefully this one lasts more than a few weeks before a blade comes apart.

 

[Vizier87]

Wicked TCM!!!! I've built a generator of my own too (fits my palm):
**broken link removed**
30V at no-load, 3500 rpm. Neo-mags from hard-drives, plastic pen tubing, perspex end-bells and some titbits.
Very inefficient compared to yours.

How's your output regulation?

 

[tcmtech]

I am not exactly sure how my output regulation is going to work. By the numbers it seems good and the test spin on the lathe showed good results as well but still when put in the real life working environment and aplication this stuff always seems to have a slightly different working characteristic that what the bench testing shows. The design is electrically tunable being all the control stuff is at ground level and easy to reach this time.

The weather forecast says near no wind for at least a week now which is typical of whenever I get a wind generator up and ready and actually want high winds for full testing and tuning purposes.

 

[HiTech]

A Leece Neville alternator with an output at a mere 100 amps? I thought they were built for and known to be amongst the heaviest duty, highest output alternators for big rigs? 200 amps+ output is more like a Leece unit.

 

[bryan1]

It is typical when you put a wind genny up there is no wind for a week or more....
Soon I'll be ordering some 50x15mm N52 round neo magnets to make a dual axial flux genny that should be in the 3kw range for 24 volts. Once I get this project going like this thread it should of gone in the RE section, I'll make a thread detailing how easy it is to make a 3kw wind genny......

Cheers Bryan

 

[tcmtech]

A Leece Neville alternator with an output at a mere 100 amps? I thought they were built for and known to be amongst the heaviest duty, highest output alternators for big rigs? 200 amps+ output is more like a Leece unit.

Leece Neville makes all sizes of alternators from 12 volt 35 amps up to at least 24 volt 370 amps and countless other voltages and current capacities as well.
This is just one I got from the junk yard for $10 so what do you expect?

I used what I had available that had a power rating in the realistic working range I expect to have for this system. I do have a 4800 series that puts out 28 volts at 185 amps but needs to be rebuilt first.
There was just no point in putting a 4 - 5 KW capable alternator on a 1 - 1.5 Kw wind generator.

Once I get this project going like this thread it should of gone in the RE section, I'll make a thread detailing how easy it is to make a 3kw wind genny......

If you want one I can write this up as a DIY thread for the AE section. I have loads of other pictures and other referance information and can include much more detail in how I did everything including the alternator rewire, the frame design, and the tower install as well.

 

[tcmtech]

Well I had some wind today finally, 15+ MPH.

I am not happy to report it but the Powermax blades I bought are junk. **broken link removed**
I would have written them a bad review on their site but they took out the written review part and only leave you with a weak star rating system which doesn't allow anyone to say anything about why they rated them as they did.

These 9.5 foot turds have almost zero starting torque even at 15 MPH. Without the alternator connected they can barely start up the gearbox by itself even though that can be turned just by the weight of a common vice grips hanging on the main shaft in a horizontal position. They dont have crap for power either once they do get up to speed and they are noisy as well which is most likely from the rough leading and trailing edge seams.

When I get a chance I am going to have to take the whole unit down and make an adjustable pitch hub so I can change the angle they sit at to try and improve the starting torque plus clean up the leading and trailing edges to see if that quiets them down providing that it doesn't cause them rip open like the their competitors blades did last year.

For referance I had the Windmax blades from their competitor last year. APPLIED MAGNETS-Neodymium Magnets-Rare Earth Magnets-Ceramic Magnets-Industrial Magnets-Magnets Wholesale To The Public
Their blades had great low speed starting torque and good running power but where poorly weight matched and very noisy from the factory. Plus due to bad workmanship in manufacturing the three sets of them I had all died an early death from manufacturing flaws. Two blade sets had the seams opening up on them and the third set had one blade tare out at the root. Their base problem was that they had severe voids in the fiberglass due to sloppy craftsmanship and poor manufacturing processes which is why I quit using them and changed suppliers.

So if you are going to build your own wind generator I highly suggest you dont buy blades from either of these manufactures. From what I have seen now I can honestly say that I have made better and more efficient blades by hand from old 2 x 6 scrap wood using a table saw and belt sander.

 

[shortbus=]

Hi, the latest issue of Nuts&Volts magazine(Mar2010) has a good article on wind gen blades.

 

[tcmtech]

I am planning on going back to doing my own blade work from now on being I have some experience with making blades.

A number of years ago a buddy of mine and I made several sets that worked very well and some lasted for many years despite their being made out of unprotected low grade wood we had just sitting around our farms.
We basically just copied the old Wincharger, Paris Dunn, and Jacobs blade designs with a bit of resize work to match the sizes of wood we had and to improve the strength in some ways.

My intentions are to get my brother to help me out now that he has a good wood working setup in his garage being my buddy went south a few years a go and never comes back for very long so I cant use his wood working equipment anymore.

My thoughts are to make a 10 foot set out of laminated oak with over sized roots and a fiberglass or preferably carbon fiber shell. My intentions are to have a 10 foot blade set that can run at over 1500 RPM without damage and still last for many years. We built a basic bare wood set that did that without problems and lasted until his tower fell over.

We had no problems running a few sets we made at unloaded tip speeds right into the sound barrier which was pretty impressive considering they where made of old unprotected pine 2 x 6 and 2 x 8 framing lumber!

Apparently these factory built fiberglass ones can't do half of that before they fly apart or rip open.

 

[tcmtech]

I have the wind generator back on the ground again. This time its getting set up as a direct drive system using a massive permanent magnet DC servo motor as the generator.
The motor is rated for 120 volts at 1000 RPM and has a 33 amp continuous duty current rating in a stalled condition and a 50 amp continuous rating while turning. Plus a surge capacity of over 150 amps for 1 minute. The blades should break off before the motor ever gets over worked!

Being a direct drive PM DC system now I can motor it up to speed if these blades cant get going on their own and I also have the ability to put it into a shorted stall to park it during excessive winds. The nice thing about having built homemade wind generators for over 20 years now is that I have came up with an easy to modify modular design that is simple to take down and rework!

I will try to get some pictures of how it is set up tomorrow and also of how I work on my tower too.

Any bets on whether the blades will tear out at the root first or that the leading edges will split and open up first?
I will be surprised if they make it more that a few months before either of those happen provided I dont take them off and toss them in the boiler and burn them first.

 

[tcmtech]

Its back up and flying again!

I have everything hooked up and the local weather site says we have 13 MPH winds too! (dead calm here actually. )

I back fed it and spin tested it to around 500 - 600 RPM without problems and it flies smoother now as well. I did a little blade work while it was down to clean up the noise.

It looks basically the same except for being direct drive and having a much bigger DC motor on it instead of the gearbox and alternator system.
So who knows, maybe it will work for a while again. And hopefully I can get some more GTI design and testing done now as well!

 

[Mikebits]

The gen looks like it is exposed to the environment. Will that present a problem if it rains?

 

[tcmtech]

Its a sealed motor that is designed for rough service so being outside doesn't harm it one bit.

 

[tcmtech]

So far its put in over 12 hours of run time with regular incursions into the 1 KW+ range while dumping its power into my heaters. The average so far seems to vary around 400 - 600 watts for the 12 - 15 MPH winds today.

It seems to spin smooth and the rotor sounds are not noticeable in the house.
The new GTI system is next!

Also it looks pretty impressive from the main county road a half a mile away!
(at least it moves when the wind blows now. )

 

[tcmtech]

Too windy now! Today I am getting wind at 20 - 25 MPH with gusts to 35+ MPH.

I was topping 2800 watts into my heater loads a number of times. Thats 40 amps at 70 volts at the house not including what I am loosing in the roughly a 1/2 ohm resistance in my 600 feet of line for the round trip down and back.
Best guess is a 1100+ RPM rotor speed at that output which is way too fast for these blades.

I tested the short circuit parking system and it works well!
The nice thing about massive permanent magnet motors is they have incredible stall torque!
In the short circuit stall mode I have around 15 - 20 RPM on the 1/2 ohm line load.

Well at least its generating this time!

 

[Hero999]

Do you actually use the waste head to say heat water?

The title of this thread annoys me because I keep reading it as "wind up generator again", it must be my dyslexia playing tricks on me.

 

[tcmtech]

So far its just heating the air in my workroom.
Basically the heaters are standing in for a dedicated load bank that will go with the GTI I am working on today.

The room was warming up nicely when I was dumping 1500 - 2000 watts into it but the generator rotor speeds where getting to high being I dont have enough low resistance high wattage load for it yet.

I had not planned on needing a load bank that could handle 2.5 Kw at 60 volts for long term usage as of yet. I have a 5 KW heater element form an electric furnace that I cut in half to work on 120 volts so at 60 volts it is capable of 1.25 kw load capacity but I dont have sufficient fans or air circulation to keep it from burning out.

At least I built it with a parking brake system that can bring it down to a near stall without actually having to go up the hill and do a mechanical shut down!