Lower, replace, lift - 6 years for photos

[Dave B]

I just completed replacing my stator (more efficient in lower wind speeds) and this time after 6 years decided to take the time to take some photos during the raising and lowering. The hub of my 16' machine is 86' AGL on top of my modified Rohn 55G tower. The gin pole is 52' as are the guy anchor distances from the base. I've pulled this up many different ways in the past but the grip hoist is by far the safest and most controlled way to go, is portable and requires no power other than a bit of a manual workout. Murphy's law is of course in effect, I have stopped the wind for the past couple days since installing my stator. I can't wait to see what this will do now charging my 8  L-16's @ 48 vdc. All fun stuff,  Dave B.

[oztules]

Never get tired of seeing windmills in all their stages Dave..... thanks for taking the time.

Do you have an idea of your average daily KWH for this monster.

I currently only use my 4m unit to recharge the electric car (read bomb)  which it does easily....... so I don't know what it will do if I use it continually..... will get to using it properly  someday I hope.


Very nice looking area you have there.

..................oztules

[TomW]

Nicely done! I seldom remember the camera "during" just before and after.

Thanks for the share.

Tom

[Dave B]

Oztules,

  Thank you for the compliments. Working with an 8000 lb grip hoist certainly allows for relaxed time during a lift and that was the perfect time for me to take a break and take some photos. This machine has been through many variations and originally was set up as a 3 phase AC direct hot water heater. Once tweaked for start up and decent output there were several times in the 25 mph range it would crank 3000 watts. Since then it was a 24 volt charging system and recently changed to 48 volt. The stator I just replaced performed well in the 10-20 mph range and extremely well 20+ mph with furling set at about 25 mph. 1000+ watts at about 15-20 MPH and would really take off beyond that up to furling. My new stator is thinner with heavier guage wire, fewer turns and closer air gap for cut in at about the same at around 80-85 RPM. I tweaked the tail a bit also and believe now I will have room to bring this in around 300 watts at 10 mph up to maybe 2KW around 20 mph. Previously I held this to about 225 rpm max this may be somewhat less now I expect. Time will tell, I have complete realtime logging with internet remote as well. Just waiting on some real wind for data.  Dave B.

Never get tired of seeing windmills in all their stages Dave..... thanks for taking the time.

Do you have an idea of your average daily KWH for this monster.

I currently only use my 4m unit to recharge the electric car (read bomb)  which it does easily....... so I don't know what it will do if I use it continually..... will get to using it properly  someday I hope.


Very nice looking area you have there.

..................oztules

[kitestrings]

Looks great and nice pics Dave!  Keep us posted on how it performs.

~kitestrings

[12AX7]

A 52ft. gin pole?   *yikes*

Looks good!

ax7

[Dave B]

Got some wind, not much but enough to get some figures. Batteries at about 95% SOC and 10 mph winds showing about 250 watts average. Brief gusts of 15 mph peaked at 720 watts and I could tell it was getting light in the tail already at this output as expected. I left it conservative knowing that now I can maybe make the tail area larger and or add some weight also. I am very familiar with this machine's performance and not adding too many variables at once I can really nail it for what I am shooting for. As is I doubt it will hit 2KW but I really like the slower rpm and very well behaved performance and predictable furling. I'm going to let it run and give it a work out with the batteries at different SOC and as much weather that it can throw at it. After many hours logging up to and then above 35+ mph will I then have a very good handle on the new stator performance. Right now I couldn't be happier, I pegged it right on with what I expected to be able to do. I am in no hurry to push being greedy.  Dave B.

Looks great and nice pics Dave!  Keep us posted on how it performs.

~kitestrings

[artv]

Hi Dave,.........that is a thing of beauty!! ...........just makes me want to learn alot more ,....awesome....artv

[wpowokal]

Interesting to see you have attached guy wires to appropriate points on the gin pole, do you see any flexing in the gin pole in operation?

Allan of the jungle

[Dave B]

 This is all qualty hardware specific to and all purchased through Rohn. The tower guy backets cradle the tower so the guy wire pull is against the brackets not directly against any one member of the tower leg component. This gin pole weighs over 700 lbs, there is no flexing when it is all adjusted properly to lift or lower. When down I have additional support under it to help with adjusting the guy tension of the middle location. To protect myself and others I decide against providing any other tower specifics. Thank you for your comment and review of my posting.  Dave B.   

Interesting to see you have attached guy wires to appropriate points on the gin pole, do you see any flexing in the gin pole in operation?

Allan of the jungle

[halfcrazy]

80 ish feet of Rohn 55g will not flex much any how that is some rugged tower. Looks good Dave I wish I had such a nice tower. Do you ever climb it for little things versus letting it down?

[Dave B]

There is a long story behind this tower, I'll just say in it's previous life it was 140' with gobs of antennas, dishes etc. hanging off it. It was normal for a crew of 3 to climb it for installations and regular maintenance. Rohn sells the standard 55G tower package up to 300'. I promised myself that I would not even consider climbing it without another experienced climber and the proper equipment and training. I believe I could do this if that were the case but I have no plans to. I could not imagine my home brew machine installed on anything of any height not being a tilt tower or at least having some type of winching or crane system. Anyway, it is as you say a very robust tower that I am very fortunate to have. The wind has all but stopped here again, I'm ready for at least 20 MPH plus to see what my machine will do now. I am quite positive it will fully furl early and be stall limited before nearing 2KW. This is what I wanted to be on the conservative side and with time maybe tweak it up a bit. I've got some solar voltaic questions for you that when I get them together I'll email you. I'll be in touch,  Dave B.   

80 ish feet of Rohn 55g will not flex much any how that is some rugged tower. Looks good Dave I wish I had such a nice tower. Do you ever climb it for little things versus letting it down?

[Saltwater]

That tower is an absolute monster.  You are very fortunate to have that amount of land to stretch those guy wires.  Looking forward to the turbine results.

[kitestrings]

Say Dave,

I've been looking over Steve Fahey's compilation of units and related posts on furling variables.  When you have time, would you mind sharing what some of your current spec's are?  Such as:

offset
tailboom length & weight
size of tail

I'll be interested in what you observe.  At 95% SOC I would think there would not be much load from the bank, so it may behave differently - as you've suggested - under higher loading.

Did you end up springing for the exta string of batteries?  I seem to recall you were considering adding a second(?).

Good luck,

~kitestrings

[Dave B]

Kitestrings,

 This machine and geometry has been change around over the years depending on it's application. Since charging batteries the tail is approx. 48"x 32" (HxW) and the hoizontal flats top and bottom are approx. 22" each if I remember. It is made of aluminum. It is less than 1/8", I don't know my sheet metal guages but it's fairly stiff and I had the sheet metal company bend over onto itself making a seam of about 3/4" all the way around the outside edge to really stiffen it up more. The boom is 8' long steel pipe under 2" OD and the hinge angle has been lessened from the standard book ideas of way back when. I have not added to my battery bank
 yet, I invested in solar first. I know I have actual specs. and drawings some where but this should give you an idea. It's all about what works best for each individual system, application and location. There is no standard unless "it will work" is good enough.  Dave B.

Say Dave,

I've been looking over Steve Fahey's compilation of units and related posts on furling variables.  When you have time, would you mind sharing what some of your current spec's are?  Such as:

offset
tailboom length & weight
size of tail

I'll be interested in what you observe.  At 95% SOC I would think there would not be much load from the bank, so it may behave differently - as you've suggested - under higher loading.

Did you end up springing for the exta string of batteries?  I seem to recall you were considering adding a second(?).

Good luck,

~kitestrings

[kitestrings]

Thanks Dave.  I know it is not an exact science, and 'your mileage may vary.'  Still, it is interesting to see what is - and perhaps more importantly, what isn't working for folks.  And, I know you've experiemented quite a bit with different applications.

John Hiatt once say, "...I've done a lot of dumb things...I'll probably do some more."  I'd hate to think I spent all my time repeating other peoples mistakes.  I'm way more creative than that .

~kitestrings

[Dave B]

I forgot about the offset. This was originally an 18' machine and so I am quite certain the offset is 9" center line of spindle axis to center line of yaw axis. There is not much front extension of the hub so there is a fair amount if tilt back for blade clearance. After crashing the 18' blades into the tower is when many changes were made. I have spaced the now 16' blades out another 3/4" at the hub after the crash and most other changes involved overspeed and load control. I can't wait for some real wind, so far I am real happy with the improved lower end performance and it will be interesting to see where the top end is now. I'm guessing about 20 MPH @ 1600-1800 watts maybe about 200 rpm. All guesses until I log a few good days of wind.  Dave B.   

Thanks Dave.  I know it is not an exact science, and 'your mileage may vary.'  Still, it is interesting to see what is - and perhaps more importantly, what isn't working for folks.  And, I know you've experiemented quite a bit with different applications.

John Hiatt once say, "...I've done a lot of dumb things...I'll probably do some more."  I'd hate to think I spent all my time repeating other peoples mistakes.  I'm way more creative than that .

~kitestrings