single phase VAWT update

[(unknown)]

The 6 coil single phase stator failed to produce a satisfactory output under real life wind conditions.  I increased the coils and magnets count to 8. The increased magnet count showed a design flaw of my double rotor design, the increased magnet count created enough force to pull the rotor away from the seated bearing on the central shaft.  On the plus side, the new vertical blade design preformed very well. Under light wind conditions the RPMs are high enough to create the illusion of spinning backwards when videoed with a digital camera.    

http://www.youtube.com/watch?v=3O3Ap1HAWzE  

[gotwind2]

I would think you would get considerably more power with steel rotors rather than chipboard?

The vertical blade design looks pretty good though.

Ben.

[KilroyOdin]

Hi, thanks for feedback. I am using a plastic decking material to fabricate the rotors, it is easy to work with and machine. Are there any links that has a side by side comparison showing the differences in output using metal backed rotors verse non-metal backed rotors?

[electrondady1]

here is a side by side comparison for you,

mags on chipboard = suck

mags on steel backing = good

lol

at the very least you will double the output of your existing devise

by placing the mags on steel rotors of the proper thickness.

[KilroyOdin]

Nice juxtaposition.

[wdyasq]

I've been hoping someone would ask where the magnets are running in relation to the coils. IF they are on the outside of the coils, that is a problem too. But, there is not way of telling from the photos.

You DO need a ferrous backing plate. If you can indicate where the magnets cross the coils, it may help in diagnosing your lack of current.

Ron

[dbcollen]

Your magnets look tiny compared to the holes in your coils. That combined with the lack of steel backing for your magnets should pretty well explain your lack of power.

Dustin

[KilroyOdin]

Hi, the magnets are ¾ by 1 inch cylinders N-45's, with a pull force of about 79 pounds. I have position them to cut the coil at the midway point so the coils are perpendicular when intersected by the lines of force of the rotating magnets.  When I tested the alternator using a variable speed lathe the six coil configuration produced electricity at  12 volts and above at an rpm range higher than 1000 rpm.  I have not been able to test the max speed produce by the new blades because of the cold weather. I believe what is happening is the new blade design reaches a max rpm at low wind and remains constant even when the wind speed increases.  That combined with the fact that the 6 coil configuration had 250 turns each made the air gap much greater than it should be for low rpm applications.  I plan on using the 6 coil stator to experiment with the metal back rotor recommendation to see if it has any effect on the output.   I greatly appreciate any feedback received and enjoy the humorous comments as well. It is a great distraction from cabin fever in the cold months.

Live in the present and plan for the future.          

[CmeBREW]

Hello,

      Good video. Nice looking Vawt rotor. Of course once you hook  a load to it, it will slow down some.

Big yes to the steel backing. Gotta have that. Even sheet metal on the back side would be better than nothing. I always wondered about trying to use some cheap epoxy to tightly glue a few circles of sheet metal together with clamps and two pieces of plywood as glue blocks.  Not as good as solid though, but maybe worth a try if cheap.

I know that 'gearing' is not used that often around here, but for a VAWT I believe I would certainly do it now instead of attempting a 'direct drive' alternator-- but only if there is no cogging. I would not try it with a dc motor including Ameteks for that reason.  The cogging would be multiplied by the gear ratio.

The direct drive VAWT alternator I made had 20 poles (and nice 1/4" thick steel rotors)  and DID have a cut-in of only 70rpm. But the problem was it is exactly like the gearing on a 10-speed bicycle.  Going down that low of a cut-in was like a kid trying to start off pedaling the 10-speed bicycle in 10th gear, and thus the TORQUE to turn it was EXTREMELY difficult at this 70rpm cut-in.  So it was always Severely (mechanically) STALLED (Too much TORQUE needed) unless a hurricane came along-- and even then I only got 62 watts max during a brief giant gust.

One of the great easy things about HAWTs is you get to proportionally divide up (or;reduce) this hard to turn TORQUE with increased (easy to turn) SPEED.

Of course, in the end, TORQUE x SPEED still equals the same total power present.

But I have found it extremely difficult to guess a PERFECT matched direct drive alternator for a VAWT.  I think It would be much easier (and cheaper) to do simple gearing for higher speed and then you can get more leeway to get into a decent efficiency range for the alternator. (just my opinion from my frustrating experiences)

Something you might find useful:

I just got a low friction rubber flat belt (5/8"wide by 1/8" thick by about 3 feet diameter) at a car parts store like 'Autozone'. (only $13)

It works great on my pedal generator. Sure seems as easy to turn as a chain and sprocket.  I use it on particle board circles as 'pulleys' I cut out with my jigsaw.

The belt also grips very well on plastic pvc end caps--as the 'small pulley'.

It will work with your decking material board too. Simply cut out different size circles until you get the exact 'gearing' from your Vawt rotor to your Vawt alternator. (I would make a 'weak' (not strong/powerful) alternator with a cut-in around 120-220rpm and gearing of 3:1 to 5:1 ;3-5 times the speed for the generator)

-Sorry, Difficult to explain in few words.   Good luck with it. You are on a very bumpy road.

[hiker]

try some used sawblades--

[electrondady1]

one thing that has not been mentioned is the dia. of the rotors /stator

or what can be fitted into your pipe /alternator housing

you will find that the magnets you have are smaller in dia. and about twice as thick as most that are used for alternators around here .

if this was my project i think i would place all 16 magnets on one 3/8" thick steel rotor,

 about 8" in dia.

a would use a second  rotor without magnets for the flux return path.

it looks as though you are trying to cast the coils in place inside the housing and that is very difficult to make right with no adjustable  wiggle room ether on the stator or on the rotors.

mind your fingers!!