Wind power generation

[Matty272]

I'm in the habit of stripping things down before getting rid of them - it drives my wife crazy. That means I've got, amongst other things, motors from household appliances such as a washing machine and a tumble dryer.

I'd like to use one of these as a simple wind powered generator. We're near the coast and almost always have a decent breeze.

My questions are: How do I regulate the power out of the motor when used to generate? I'm ex-navy and remember the greenies discussing over-voltage and over-current protection, but am not sure where to start building either of those circuits.

I'm aware that I'll have to store the energy somehow and am considering 12v car (van, more likely) batteries for this before using the power available. For the moment, though, I'm just looking at the generation side of things.

I've done some searching online, but many of the things which come up are either commercial units (I don't want a black box, I want to understand what I'm using) or the whole things seem, for want of a better word, dodgy.

Could anyone point me in the right direction, please. I'm very happy to do my research and reading (then come back here for advice on what I've learned), just need a pointer to get me started.

Searches for "over voltage protection circuit" come up with many results showing a 5v supply, my suspicion is that I'm going to have a few volts more than that.

[Matty272]

From my reading so far, I understand that I'll also have to have protection for my storage for when it's fully charged, but that's for later research

[tggzzz]

Start by looking at http://www.withouthotair.com to see what you could reasonably expect to achieve.

If it is worth achieving, you would benefit from understanding "maximum power point" (MPPT) controllers.

[Matty272]

Thanks tggzzz.

Anything that I get out of it is worth achieving even if the only thing I get is some knowledge

Now going searching for those

[jolshefsky]

If you're looking for simple, try driving the motor with an electric drill and see if there is any voltage output. If you have, say, an AC induction motor, it won't convert (basically) any energy and you'd need to redesign it with permanent magnets, and it wouldn't be worth it for you to go through all the trouble of building a windmill to get no energy converted with the wind either.

Also, if you're looking for simple, Savonius or vertical-axis wind turbines are. They're not the most efficient, but they don't have the problem of over-revving since the rotor tip speed is strictly less than wind speed. Horizontal-axis turbines are way more efficient, but they MUST be loaded as to not over-rev which means an over-voltage shunt regulator (to dump excess power), an emergency braking system (in case of wind powers that overwhelm the braking of the generator—avoidable with undersized blades), and possibly a furling system to deflect the rotor away from the wind when it's way too strong.

[m100]

Not using your existing motor but IMHO this design is proven and is a good starting point.

http://www.scoraigwind.com/download/index.htm

http://www.scoraigwind.com/pmgbooklet/itpmg.pdf

There is a mailing list on Yahoo for the latter and its derivatives, can't recall the link

[ConKbot]

If you're looking for simple, try driving the motor with an electric drill and see if there is any voltage output. If you have, say, an AC induction motor, it won't convert (basically) any energy and you'd need to redesign it with permanent magnets, and it wouldn't be worth it for you to go through all the trouble of building a windmill to get no energy converted with the wind either.

Also, if you're looking for simple, Savonius or vertical-axis wind turbines are. They're not the most efficient, but they don't have the problem of over-revving since the rotor tip speed is strictly less than wind speed. Horizontal-axis turbines are way more efficient, but they MUST be loaded as to not over-rev which means an over-voltage shunt regulator (to dump excess power), an emergency braking system (in case of wind powers that overwhelm the braking of the generator—avoidable with undersized blades), and possibly a furling system to deflect the rotor away from the wind when it's way too strong.

AC induction motors can be used as generators. http://www.qsl.net/ns8o/Induction_Generator.html There has to be enough residual magnetism in the rotor, and a cap on the output to provide reactive current, and it can be used as a generator.  Its frequency would be variable in a wind turbine, so rectify it, and feed it into a charge controller for your battery bank. As stated earlier, you cant remove the load from the turbine, so a solar charge controller wont be appropriate, as solar panels have no problem with being open or shorted. A wind turbine wouldn't appreciate either of those conditions. 

[G7PSK]

Have a look at this site, it is for people making wind and solar power plants big and small.http://www.fieldlines.com/index.php

[johansen]

Most motors from washing machines and driers are 36 slot 4 pole machines.

i do not recommend a direct conversion, but rather rewinding it for a 30 pole machine.
use www.emetor.com/edit/windings/  to show you how to do this.
20 pole 24 slot is also good, as is 22 poles 24 slot.

you'll need a lathe or a milling machine to do this, and the long skinny magnets are sort of expensive.

i used 1/8th inch thick 1/4th inch wide 2 inch long magnets to make a 30 pole 36 slot conversion from a 1/3rd hp 6 pole induction motor.
the results are at 1/2 hp electrical output at 825 rpm i was able to get 75% efficiency, with most of the losses in the copper windings.

[Matty272]

Many thanks to all who have responded.

tggzzz:
I got myself bogged down a little bit with the MPPT reading (either masses of info or dumbed down too far on the things I found), but if I understand that correctly, the best efficiency is based on both wind speed related to rotor design on the particular generator AND the actual load (in my case batteries) at any particular point?

jolshefsky:
Thanks. I will look into the simpler designs.

m100:
Looks like a good re-starting point if I don't manage to get anywhere with current motor.

ConKbot:
If it turns out to be an induction motor, I suspect I'll follow a different route. Thankyou for posting that to help, though. I hope it will be of use to future readers of the forum.

johansen:
The link isn't working for me this morning, but if what it shows is easy enough for me to do, then it's possible that I will be able to give it a go and learn from it.

[LabSpokane]

Matty,

In the US, the standard DIY wind generator solution seems to be a Delco (GM) alternator in which permanent magnets are installed on the rotor. 

http://www.windbluepower.com/Permanent_Magnet_Alternator_Rotor_Fits_Delco_10SI_p/pma-rot.htm

The same guys have a bunch of other parts that could make the process easier.