Winding your own??? 1

[nornrich]

All,

We are in the process of designing a small wind turbine for a client. We are trying to select a generator that will suite our application. Would anyone have any guidance in this matter? Would it be best to select an off the shelf generator, or design one that we can have wound by a transformer house?

Regards,

Rich.....

Richard Nornhold, PE

http://www.ovenind.com

 

[electricpete]

I assume you have looked at the available offerings of off the shelf gneerators to see how they stack up for your applcaiton. Is there something you can improve on or some feature you can provide in self-designed machine that is not available in off the shelf generator?

If the answer is no, I think you should buy one.

My opinion, worth what you paid for it ;-)

=====================================
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[electricpete]

And by the way if you were going to have one wound yourself, wouldn't you go to a motor ship instead of a transformer shop?

=====================================
Eng-tips forums: The best place on the web for engineering discussions.

 

[GregLocock]

I'd find the best generator that you can off the shelf (whatever best means) and then design the turbine to suit it, rather than vice versa.

Cheers

Greg Locock

SIGlease see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[OperaHouse]

Just what do you call small? Wind generators are a pretty dumb technology. Almost anyone can make a turbine that works in some wind condition. There are a lot of mechanical and electrical trade offs. What technical expertise are you bringing to the table? The only need for a custom winding is to add a low speed coil. A compromise that leads to overall poor performance. On the electrical side, I see a lot of things out there that just make me gag. My advice is to find a really good electronics house, go with higher voltage coils and sophisticated electronics. This could also be something that the end customer is be unable to maintain. I really don't have any idea what you are actually trying to design.

 

[nornrich]

Thanks for everyone's input. We are still in the early part of the process of designing the mechanical and electical portion of a small 1-3 kW horizonal wind turnbine. I was looking for some initial guidance.

Regards,

Rich.....

Richard Nornhold, PE

http://www.ovenind.com

 

[MikeHalloran]

You might find what you seek in Mother Earth News.

Some kinda propeller on a shaft, modest Poly-V speedup, a car alternator, battery, inverter...





Mike Halloran
Pembroke Pines, FL, USA

 

[nornrich]

MikeHalloran,

We are also looking at those options, but the efficiencies that you get when you aren't optimized for your final transmission output speed are horrible.

Rich.....

Richard Nornhold, PE

http://www.ovenind.com

 

[MikeHalloran]

So now you have to instrument the installation well enough to measure the efficiency, so the client can compare it with his friends' toys.

[
When those guys buy boats, they will pay obscene amounts of money for niceties like mirror finished stainless steel surfaces everywhere. Yes, it can be done. No, it can't be done profitably.
]



Mike Halloran
Pembroke Pines, FL, USA

 

[LionelHutz]

Is this a 1-off or a production unit?

In general, you are looking for a low speed alternator with very good bearings that will support the blade assembly and take the wind forces. In that regard, it seems that the permanent magnet 3-phase "wild" alternator is the most favored solution for small machines.

If you have the capability, pair it with good electronics which will maximize the output drawn from the alternator and convert the wild voltage and frequency into line voltage or battery charging voltage. You'd have to also know the blade power output curve and draw as much power as the blades can produce at their operating speed to maxumize this solution. Think something similar to the solar MPT? - maximum power transfer? technology.

If this is a 1-off then I would build the alternator myself or have someone build it following the same construction principles of the bigger units shown at

http://www.otherpower.com

Those guys have been doing it for years and just keep stepping up their power. First time I saw their website they were building 800W units. Now, I see they are dabbling in the 5kW range.

Mike - if this is commercial then you have to sell something that will be competitive against your competition....

 

[LionelHutz]

oh, this is a good site to read too;

http://www.scoraigwind.com/

 

[nornrich]

LionelHutz,

Thanks for the direction. This wouldn't be a one off, but it's not going to be a million units per year. A low rpm alternator sounds like where we want to head. Fortunatley we don't need the alternator bearings to handle the load, as we are stepping up the rotor rpm through a drive train. We are targeting a 160:1 ratio on the drive train.

Regards,

Rich....


Richard Nornhold, PE

http://www.ovenind.com

 

[LionelHutz]

That sounds like a very high step-up ratio. I'd expect blades on a 3kW machine to run between 100rpm to 200rpm or so and that would be 16000 rpm to 32000 rpm at the alternator?