A different alternator for a VAWT?

[skipinder]

Hello everyone,

I'm new at all this, but having fun learning new stuff every day.

I want to have a go at building my own vertical axed turbine and judging by the praise it gets here I think the LENZ2 is for me. Many, many thanks to it's creator for his generosity in sharing the design, and bravo for the ingenuity (is that a word? it is now...)

I also spend a bit of time on instructables.com and while on there have come accross another generous man who has shared his innovative alternator design for VAWTs (his is on a savonius), which uses the tip speed on the base of the turbine rather than the axel speed.

http://www.instructables.com/id/Build-a-Savonius-Wind-Turbine-or-VAWT-to-make-elec/

I was just wondering what all you brainy folk thought of his design and if you could maybe see improvements or possible setbacks.

Also, would you think it's adaptable for the LENZ2?

 ps Sorry if this question has already been asked, maybe I didn't look long enough on here for a similar post...

[ghurd]

It is not at all efficient.  The magnetic circuit is not complete.

Meaning it takes more magnets, and more wire.  More wire means more resistance, and more resistance means less output.

He understands that and mentions some related issues in his responses, and I believe his design is mostly to get 'something' with greater ease of assembly.

G-

[skipinder]

Would elaborating his design help at all? ie Putting magnets behind the coils, connecting all the coils with a steel strip etc.

Has this design been seen/tried before?

[ghurd]

The more it is improved, the closer it becomes to an AC induction conversion, just a lot larger diameter.

Peter's latest FEMM simulation may be interesting.  250KB. Not for dial-up.

http://www.fieldlines.com/story/2008/3/18/11104/9513

Placing magnets behind the coils would be quite a task.

A dual rotor would be cheaper, simpler, easier, and more efficient.

G-

[finnsawyer]

I think you might find it instructive to check this link:

     http://www.fieldlines.com/story/2006/4/21/16237/9933

Note that in an actual build the coil sizes would be such that they match the magnet sizes like the three phase design.  The particular configurations shown were chosen to illustrate the basic principles.

[vawtman]

Hi Skip

 I'm working on a different alternator design for a vawt also.This one will have an outer rotating band of steel.

 I'm just comming out of hibernation now.

[tecker]

 Most Vawts only support a 180 degree duty cycle .I 'm still trying to stretch this out some what but a lot of the duty cycle goes into regageing the drag on most Vawts.

[tecker]

 The alternator in the pdf is a temped in there . Big mags are wasted on such a setup. The thing adout tipspeed is while the frequency is increased  a load would be one to one and most certainly stall the rotor.

[skipinder]

Hi vawtman, can you explain what we're looking at here? Does this bear any ressemblance to what I've been looking at?

[vawtman]

The rotor on top of the shaft is what i'm working on the rest is just a test stand.

 A 32in. dual rotor radial in the future.

 Mark :v)

[fcfcfc]

Hi:

Just a note, you can not "stall" a pure drag VAWT. The slower it goes as the wind gets higher, the more torque it has.... Ones that have a "mix" of drag and lift to their design, the story might change a bit depending how much of the power was from each type of aerodynamics...

.....Bill

[tecker]

I follow you there I think though it's close to the same thing as the the rotor dips below charging voltage .My point is that the if you meet the torque at the outer diameter with around the same load it's not going to over come that load .The mechanical advantage is at in the center point.