| T O P I C R E V I E W |
| chris_psmith |
Posted - 31/12/2007 : 18:43:00
Well after a day in the garage the first half of my Benesh VAWT is complete, just got to assemble the second one to stick on the end of it, each one is 500mm diameter and just under 1 meter tall.
Thoughts / comments welcome...
http://www.otherpower.com/images/scimages/9158/ben1.jpg
http://www.otherpower.com/images/scimages/9158/ben2.jpg
Off for a beer now.
Happy New Year
Regards
Chris |
| 9 L A T E S T R E P L I E S (Newest First) |
| chris_psmith |
Posted - 23/02/2008 : 16:51:26
The result of 2 hours spannering
My wind speed meter!
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| chris_psmith |
Posted - 23/02/2008 : 11:19:04
2 hours spannering later and its much better, the pillow bearings had so much drag that the top one had stripped the thread on the shaft and the middle one was turning in the bearing collar.
It is now standing directly on the pmg with the top of the benesh in the stripped top bearing collar, so just about the same friction loss as it would be as a hawt.
Winds of about 5mph and it is just wanting to start, hope the wind picks up later so it can have a real test, and show just how out of balance it is.
Will post some photos later, it looks much better than before with the middle mount gone.
Regards
Chris |
| chris_psmith |
Posted - 23/02/2008 : 07:44:51
Quick update, in the strong winds we have had I have been able to get about 24V in 30mph winds, enough to blow the fillament of the bulb i connected to pieces. The issue i have to look at now is the amount of loss due to drag.
I used 3 pillow bearings with high friction and a chain gear set to the pmg, all giving quite high friction force, playing with the gearing still makes it hard to get it started in anything less than about 15mph winds.
My thoughts were all based on the fact that the vawt would be a low speed machine, but with the chain and pmg taken off, so just the friction of three pillow bearings, it would easily turn at over 300rpm in about 20mph winds, so.....
Next step is to remove the middle pillow bearing and hard fix the two blade sections together (not sure why i put a bearing there anyway instead of doing this in the first place), then remove the bottom pillow bearing and hard fix direct to the pmg.
I hope the friction reduction of two pillow bearings and a chain set will reduce the start up speed whilst allowing it to turn faster at higher wind speeds.
The friction of the 3 pillow bearings was so great that it was impossible to do any type of balancing on the blade set, as you could only get about 2 revolutions of the bldes with a good push, so any out of balance was masked by the friction.
Every days a school day, time for some spannering......
Chris |
| chris_psmith |
Posted - 26/01/2008 : 19:13:09
Well, it is up in the air, and as of yet hasn't pulled the garage down.
Pole mounted with a hinged joint at the bottom so I can raise and lower it:
http://www.otherpower.com/images/scimages/9158/end1.jpg
Both blade sets strengthened since last time with metal strip riveted to blade and screwed to end plates:
http://www.otherpower.com/images/scimages/9158/side1.jpg
Finaly lifted into place, just about managable on my own, looks beatiful with the sun setting, well not exactly what my wife said:
http://www.otherpower.com/images/scimages/9158/benup2.JPG
When I first raised it, i had a mount on the board below the roof line, but the movement of the pole as it started set the whole pole off and would have destroyed everything, so welded a bar on the top that extends to the other side of the turbine, attached 2 guy ropes on the main pole side and 1 on the end of the bar i welded on. I hope this will be enough to stop the shaking.
The pole is a push fit between two angle brackest on the wall, i was hoping the weight of the turbine and its mounts, along with the direction of the hinge would avoid the need for a very rigid mount on the wall, will have to wait and see if i am right.
I am going to let it stand for a few days to see what falls off or snaps before i attempt to mount my lovely new generator, just need some wind now.
Regards
Chris
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| chris_psmith |
Posted - 14/01/2008 : 16:54:54
I was planning mounting the pole at the bottom to a plate fixed to a slab, single bolt through it so on a hinge, then a second mounting point on the side of the garage (about 1.75m up) that would then shackle the pole, this would give the advantage of making it easy to lower for service / very high winds, or the possible disadvantage of pulling my garage wall down..... May try both! |
| gotwind |
Posted - 14/01/2008 : 16:45:17
I look forward to seeing how that works out Chris,
Make sure you have some really strong guy cables, steel into concrete block ideally.
Ben. |
| chris_psmith |
Posted - 14/01/2008 : 12:35:35
Just to update everyone (if you are interested). After a test flight stuck to the side gate frame, the balance became an obvious issue, when the wind hit about 40mph the gate and fence started to go into resonance, my wife was less than happy so i was sent out at 4.00am in my jimmy jams and a gale to take it down.
But, very strong winds and no damage to my VAWT, just my sleep.
So after reflecting on her comment of 'that goes on the side of the house over my dead body' (plan was on the wall right by our bedroom) I have had to have a strategic re-think.
Decided it has to be pole mounted, managed to get a 6.5m scaffold pole for £20, but now 4.5m after assesing how much was sticking out of the back of the defender!
So, pole mounted VAWT should be taking to the air over the next two weekends, hopefully divorce will be delayed...... |
| chris_psmith |
Posted - 01/01/2008 : 18:49:03
Yes, at 90 degrees to reduce any chance of stalling, just need some wind to test fly the first one.
Rgds
Chris |
| gotwind |
Posted - 01/01/2008 : 17:44:38
Chris.
I wish you well with this design, I assume you will mount the second at 90 degrees.
Vawts are tricky, but not impossible...
The Futures Green - Getwind of it. |
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