10 foot PMG Test Mill

[brianc4]

I finally got some time to post some info & pictures of Our fist test windmill. It was a quick & fast project in oder to get something up & flying so I could begin to get some practical hands on experience with windmills.

The mill is setting on a 25 foot test tower in front of our showroom and is not near tall enough to get into clear air but it works well enough for testing purposes. We used PVC blades & a 2.5 Hp DC motor for the generator and in testing it puts out appx. 427 watts at 12v in 15 mph winds.

The furling mechanism is a direct blade tilt design & works very well. The balance point of the motor is set at 100 lbs. and in 16+ mph winds the motor & blades begin to tilt up. The spinning blades act as a big gyroscope and even if the wind stops abruptly the motor sets back down gently. We put some big rubber bumpers on the tilt plate just in case it set down hard but I don't think their necessary.

The Mill did have one disaster & we shattered the ends off of the PVC blades!

When We pulled the mill down for new blades & We found the culprit. The two bolts on the foot mount base of the motor had worked loose and allowed the whole motor and blade assembly to move. The blade tips hit the mast of the tower and clipped the ends off of the blades. Amazingly the all sheared off equally and the balance was still perfect, no vibration what so ever! The bolts have now been loctited & if they give me any more trouble they will get spot welded.

The last picture I call "Waiting for the Wind" We got the new hub & fiberglass blades on & wanted to check out balance before putting it back on the test tower. The wind was blowing nicely the whole time We were getting the mill rigged up on the forklift but as soon as we backed out of the shop into the driveway it stopped. However We had plenty of rain that day hence the tarp on the forklift seat.

It has been a fun project and I have learned alot and wish to thank all who have replied to my previous posts I really appreciate the help. I have moved on to a 10' Axial Flux design with furling tail & will post pictures of design & progress as time allows.The "Test Mill" will take up permanent residense on a 40' Tower in my Parents back yard hooked to a bank of L-16 batteries & a 5,000 Watt inverter to power the lights TV and VCR in the family room & the lights in the bathroom.

[RUFUS]

The furling mecanisim, have you seen it in action yet?

Dose it work smoothly

                                      RUFUS

[brianc4]

The furling mechanism worked very well with the PVC blades. We have had a very windy year in Southern Indiana. Winds have been over 20 mph on a fairly regular basis & the blade lifted flawlessly & smoothly every time! We have not had as much wind since We put on the fiberglass blades but I expect it to work fine with those as well.

The design is not mine it was in some information on the internet but it looked interesting and worked well. The new axial flux machine I am building will have the furling tail design which is a little simpler to build & should weigh less. Figured I would build both types and then decide which one I like best.

Brian Clark

[RUFUS]

I have aquired 3 good sized 2 phase servo motors

with really good low  speed output and mulling it over

i havent worked out a furling mechinisim until i saw

what you did and i think it might work for me too,

could i trouble you as to where you got your info from,

i'm curious as to the math involved, kentucky windage has

always been good to me but am at a stage where i like

to get the details straight too. by the way nice job

on the mill

                                    RUFUS

                                       

[brianc4]

RUFUS,

I got the information from a site called www.poormanguides.com

The info packet is called The Poor Mans Guide to Wind Power & Battery Systems.

It has charts for force against the blades based on diameter at various wind speeds, a handy piece of software for analyzing dc motors for wind turbines, diagrams for building a battery desulfater, (I built one from his schematics it works great!),patterns for making PVC blades and lots of other info.

The info is $34.90 and is instantly downloadable in .PDF format. Lots of good information on low buck wind projects I do not know if it all works but what I have tried I have been very happy with. In my opinion money well spent.

The web site explains way better than I can about the additional information contained in the guide

Brian Clark

[CmeBREW]

Congrats. Nice looking mill project there.  

I also have a fairly big DC motor mill that has the tilt back furling. So far it worked great even in very big winds (40+) with the PVC blades. (I used 6" pipe //yours looks bigger like 8")

But now I just made faster 8' wood blades for it, and I don't know how the furling will do yet?

I have a question.  Does that motor hold back the blades adaquately when you short the wires together during or before a wind storm?

10' diam blades is a lot to hold back when a rare 60mph gust hits it.

Can't wait to see the results of your axial mill.  

[brianc4]

CmeBREW We found a nice piece of 12" pipe for the blades & even though the tips got broke I am planning on trimming down the ends & putting them on a 1.5 Hp DC motor for a small mill for my father & law.

As far as shorting the wires for a brake I havn't tried it yet. If the weather holds up I will lay the tower over Tomorrow and get the mill back up & I will try it & let you know the results.

Brian Clark