Ametek VAWT failure :/

[gotwind2]

I tried a quick vertical axis project this weekend - with disappointing results....

I used 6" diameter P.V.C pipe halved and coupled to an Ametek 30v DC motor.

It seemed like a good idea in my head, but failed to spin in a 10mph wind, I guess it would work in a real gust, but never hit the 360 rpm cut in speed for 12 volts battery charging.

As TomW once suggested to me on the irc, VAWTS need to be big to get any real power out of them - He was right.

Oh well, I'll move on to the next project...

Ben.

[DamonHD]

I'm really determined to try a small VAWT myself to get some feel for how it works (so I can stop being so wet about it!) and I'll try a drag-type unit like that first since we have a plastic drink bottle about to become available!  This one won't be forepower, but I'm eventually aiming for (say) a maximum of 30W peak @12V in a reasonable breeze, ie a little more than my laptop load to be able at best to power it and provide a little top-up.

Ben, aren't these drag-type VAWTs meant to be severely limited in maximum efficiency by how fast they can move?  Isn't a lift type (even just aerofoils fitted onto existing blades such as yours) said to me potentially and actually much more effective?

From the figures I saw on a commercial site, your mill, if converted to lift, should be able to put out ~50W in a decentish wind at my entirely unskilled guess.  For that same swept area what would you hope to get from a HAWT?

(Anyone got a link for wind speed and theoretical power allowing for Betz that I can use?)

Rgds

Damon

[rippersoftware]

You can't direct drive an Ametek with a VAWT and get anything appreciable.  Speed up the Ametek with a belt or chain drive.

RipperSoftware

[Nando]

Your VAWT center shaft is destroying the air passing to the rear blade to add power to it.

Remove most of the shaft, to just not more than about 15 % eight, make another disk and firmly attach the upper ends of the VAWT.

To see what type of RPM multiplier you need, try to read the RPM and the wind velocity, divide the RPM by 2 to give the working RPM ( close enough), then see what is the generator Volts/RPM to calculate the multiplier gear.

Example: no load RPM = 110 RPM ; loaded RPM = 110 /2 = 55

Generator 15v /400 RPM =

Multiplier = 400 /55 = 7.27 :1 multiplier, make around 7 to 7.9 ratio.

Your wind mill looks ( estimating) like it is 3 inch X 12 inch or 36 square inches, then you have additional losses due to the loading of the opposite half side giving braking effects, plus the shaft destroying the wind passage to the opposite half.

I made one, several decades before, I am retired now, using 2 - 55 gallon containers cut in half and placed one on top of each other with plywood for the bottom the middle and the top.

The bottom plywood was utilized to produce the gear ratio for the generator ( I do not recall the generator pulley diameter).

The wind mill produced around 50 - 80 watts ( I do not recall exactly).

Nando

[windstuffnow]

  I wouldn't call it a failure, it's simply not matched up as well as it could be... don't throw it in the parts bin just yet!

  Here's one I've been playing around with using the ametek 38 volt motor...

  It's a small 2ft dia x 2ft tall turbine, kind of a quick build for testing purposes.  The ametek is driven by a cog belt 4 to 1 .  It does about 18 watts in a 15 mph wind right now although I think the motor needs just a little less re-drive.   Here is a closer shot of the mounting...

  This actually comes up to speed pretty fast but you can tell it's being held back by the motor considerably.  Opening the circuit it runs up considerably.  

  There is a long bearing tube inside the mount tube that is held in place by 2 bolts clamping it inside the tube for now.  I purchased a couple aluminum cog gears and made some molds from them and cast them in plastic.  I plan to purchase a couple more small cogs to get a 3.5 and 3 to 1 redrive for experimenting.  Belts are cheap, the cogs are pretty pricey.

  I've been working on several different types of alternators for the unit ( some really odd things ).  Trying to find an equalibrium between cost and efficiency.  Quite a challenge so far.

.

[TomW]

Ben;

I cannot believe you actually listened to that TomW character.

By now it should be obvious he has his own agenda and it doesn't include VAWT machines.

Could be worse, you could be listening to RonB.

Cheers.

TomW

[ZooT]

Wouldn't you need more than two "cups" on a VAWT considering that when both are perpendicular to the wind it's going to want to try to spin backwards.......

And I think I've read either here or elsewhere(maybe Ed's place?) that if you're only using two cups you need to make a stack with two more on top 90 degrees  apart thus that there's at least one cup pulling all the time.......

[thefinis]

ROFLMAO

Thanks TomW I needed that

Finis

PS for those who aren't sure what the letters mean. Rolling on floor laughing my ass off

[Norm]

I think 3 blades would work better than two,

however I was under the impression that while

one 'cup' was facing the wind that is drag and

the other with it's other side is lift...much

like a sailboat can sail against the wind.

                ( :>) Norm.

[Kevortex]

OK , two things. One: Try the twisted helix design instead of the straight blade.

Two: Ametek motors are not known for good output. They simply need too high of RPM.

The generator I use needs only 120 RPM to reach 12v. Makes a big difference.

Keep in mind VAWT generators turn slower than airplane type blades. The good news is that VAWT are more efficient than HAWT type.  In other words they turn more often.

Any way, hope this helps.

[TomW]

Uh;

 The good news is that VAWT are more efficient than HAWT type.

Pretty bold statement. Got any figures or is it just regurgitated from some VAWT cult web site?

Bold statements require extraordinary proof.

I see you have been pushing VAWTs here off and on since 2005. Lets see yours. Oh, I guess if you had one that worked you would have bragged it up by now so I can only assume its just more talk.

If I am wrong, show us the proof, please or don't make questionable statements like:



 The good news is that VAWT are more efficient than HAWT type.



without some proof. Simple to prove, I would think ,if true.

Cheers.

TomW

[TomW]

I meant to type "extraordinary claims require extraordinary proof" not "Bold statements require extraordinary proof"

Just to be accurate.

T