Hello again friends,
Hope you are all finding some time to work on your fun RE-energy projects.
It's been awhile since I posted anything, so I just thought I would show what I have been working on lately AND because I now consider this 6' AC Servo motor windmill complete and useful.
I had been using a 180v (1800rpm/4.5A/ 12v cut-in about 130rpm) DC motor as a windmill on a 12' high (actually 16'; 4ft in ground) treated 4x4 for numerous months. It was almost a 7' diam. pvc prop on it. It did quite good thru the stronger winds of winter and spring.
It would have done better though as a 6' diam. mill and thus faster rpm. (as Flux had said to me in the beginning!)
As a 6' diam prop it would do upto 150 watts I'm sure. For a cheap medium size DC motor mill, not too bad.
But recently I have replaced the DC motor mill with a 3-phase AC (brushless) Servo-motor 6' diam. mill on the same treated 4x4 pole. It is starts up much easier and is doing better power and Watthours than the DC motor mill I had.
Here is the 'Ratings Label' of the AC Servo motor:
Here is the BACIC 'Tilt back' Furling method I used with a couple of bungie cords. This photo is of my previous DC motor mounted. I mounted the Servo motor in it's place:
I Had tried an 8' diam. wood prop on this but it actually went slower rpm and the power produced suffered especially in the medium (say 12-20mph) and higher (say, above 20mph) winds.
I had thought that the bigger diam. would have more leverage in the lower winds (under 12mph) in order to spin up and make more consistent low power most of the time. I can see now that I was incorrect for the most part with this ASSumption I made. It actually costs you a lot of power from being made!
So now I am understanding how important it is to find the 'Power producing curve' of each particular generator. (BEST RPM range)
Here's when I had the 8' wood blade prop on it:
Also the noise was alittle too much for me (wirling noise) in the bigger winds.
Most importantly though, Neither this Servo motor nor my previous DC motor were strong enough to hold back the 8' prop with an electrical shut-down (short the wires) when a 40mph+ gail force wind would come along sometimes at the beginning of a bad thunderstorm.
One time I found this out and it was quite frightening to see and hear. The magnets in the motor DID hold back the 8' prop during all the 20-35mph wind gusts. But once a gail force steady gust hit it, it just "let go". I was standing behind it watching.
Of course, Flux had warned us beginners about this many times, but I had to push the threshold and learn the hard way. Fortunetly, no harm was done. I got it under control with a 24' long aluminum extension pole and tied it down with a rope.(Talk about giroscopic forces!)
Just something for we beginners to keep in mind and seriously try to prevent.
Here is how I made the arbor for the Servo:
I bought this 'Hub bore' at Tractor Supply Co. for $9. They have many different sizes. This one is an inch and an eighth which is the shaft size on the Servo.
I then welded the bore to the round (almost) 1/4" plate steel disc that I had cut out with my 5 amp jigsaw and 18tpi metal cutting blade. (And frequent drips of heavy weight 'Cutting oil')
Here it is done and painted. I then epoxied a 5/16" bolt thru the tapped hole into the Servo shaft keyway groove to hold the blades on.(I actually drilled 3 bigger holes thru the plate steel to hold the wood blade hub on; not shown)
I know my welding skills are not the purdest, but I did three beads all the way around to make it strong. My wire feed welder is only 90amp but I got decent penatration.
The wood blades I made are very easy, quick, and simple:
I split a common pine 2x4 down the middle with my table saw and then used my Dado blades to cut-out the straight profile in stages. I actually made 12 identical blades at the same time with the same basic profile. One side of the blade is the flat side with no profile. That part is quick. Sanding with the finish sander takes alittle more time.
Here is the very simple blade hub I made out of 3/4" treated plywood:
I put a forth screw in each blade (not shown) to adjust the angle of the blades using small washers under each adjustment screw.
Here is a photo of the Hawt with my latest Vawt mill:
I need more time before I can post about the progression with the Vawt.
It is a LOT more difficult. Right now it usually is only doing 2-6 Watts until a bigger wind comes along and then it can do 12-24 watts sometimes.
I did get a brief 52 Watts in a giant wind gust once with this Vawt. But I am still missing the rpm range of the alternator which also is NOT very efficient due to high resistance. So I need more time with the Vawt.
I must say I really like the useful output of the 6' Servo mill. It did 200 watts in a big wind yesterday. Reducing the Prop diameter from 8' to 6' probably does TWICE the power in big winds than it use to. And my quess is 50 percent more in the medium winds. (say, 12-16mph) Low winds, probably 20 percent better.
I am sure many here have made from scratch , 6' diameter mills that are more powerful and efficient than this Servo. I am still learning, learning, and learning to do so, hopefully in the near future.
One last thing I wanted to share.
I know I should be using what little hobby money I get to buy a Wind meter to be more accurate when I quess the MPH of winds. But something else always seem to tempt me to purchase something else! Like the following Giant AC servo motor I just
had to get on Ebay:
This weighs a whopping 90lbs! The 12v marine battery only weighs 47 lbs. The big Servo is 3-phase 240v/ 2000rpm / 22amp.
It has only one forth ohm resistance in the coils. It is bigger than the photo shows.
I tested it with my slow, old, cheap Sears drill, and the duct tape broke when the Big Servo was at just over 12amps!
(200watts)
My guess is the 12 amps was at about 300rpm maybe alittle slower??
To my amazement, the 12v cut-in was exactly at 100rpm as I had calculated before buying it. (actually 13v)
As fellow member 97fishmt told me, just move the decimal one point to the right to get the cut-in. For example, 240v at 2000 rpm is the same as 24.0v at 200.0 rpm.
// or; divide that by 2 and you get 12v at 100rpm. It's always worked for him and on both my AC servos.
There is no cogging, but there is quite a bit of friction from the big bearings and the rubber seal. I may try to use it for a 25" diam.(for more speed) by 8ft long big Vawt(for more torque). But I'm only trying for a hundred watts.
But it would make a decent 10' diam. Hawt I think. (I might put it up later in the year if I get the courage)
It might do over 700 watts with a 24v system. (not sure yet)
Anyway, I was excited about it for the price.(Took a bath on shipping though)
Any comments and or questions about any of these projects would be greatly appreciated!!
