How to build a wind or trolling generator - Free report

Note- The wind blade design shown in the article can be downloaded by clicking on the thumb nail in the upper right. It's a design that has been around for over 20 years and is by far the best blade design I have come across after many side by side tests.

How to build a marine wind generator

or

How to build a yacht wind turbine

or

How to build a marine trolling generator



For full article and photos see-

http://www.tongacharter.com/report-wind.htm



By: Scott Fratcher - Marine Engineer/Captain



Today’s fuel prices are forcing many boaties to look for alternative methods of battery charging – ones that don’t use fuel. Scott Fratcher explains how to build your own wind/trolling generator to produce “cost-free” battery charging.

The wind/trolling generator presented here has been the energy producing workhorse of the cruising community for over two decades. It’s compact, has many mounting variations to suit different yacht rigs, and puts out heaps of power.

We regularly see 20 charge amps in 25 knots of wind. Sailing at six knots the trolling generator produces six continuous amps, with a drag load of 15 kg. The wind charger is the quietest I’ve ever heard, and best of all it can be built by any good DIYer in just a couple days.

Four steps to building the generator:

* Finding a motor * Build a propeller * Build a trolling attachment * Put it all together and make power





Finding a motor

The heart of the wind/trolling system is the motor. This is the only component you might actually have to purchase. Because this is a DIY article, we’ll discuss specifications to help you find one of these motors in the scrap bin, or at least know to what to look for at a swap meet.

For years boaties have used old mainframe computer tape drive motors (permanent magnet motors). There are lots of them around, now that computers have moved to hard disks. You can often find them at swap meets, and military surplus stores sometimes have them. You can also search the internet.



Specifications

We want a permanent magnet motor between 18-48 volts, with an rpm range of 200-600. The higher the voltage the more leeway you have on rpm. The idea is to produce over 14 volts at low rpm (200 or so). For an 18-volt motor to make 12 volts it has to spin at 66 percent of its rated rpm. For a 48-volt motor to produce the same 12 volts, it only has to spin 25 percent of the rated rpm.

To identify a permanent magnet motor, look for the smooth case sides, with bearings at each end. There should be no cooling fans or openings to the windings. The sealed case means the windings also last longer in a marine environment.



Testing

When you come across one of these motors, give it a quick “on the spot” test by turning the shaft. If the shaft rotates smoothly and looks to be in good shape, the next step is to cross the output leads. Again spin the shaft and you should feel instant resistance. If you don’t feel the drag it could mean loose or worn brushes, a burned-up armature, the rpm rating may be too high for this application, or it may not actually be a permanent magnet motor.

The second test is to connect an electrical meter to the generator output leads and give the motor a good spin by hand. A quick snap of the wrist should render a short but readable voltage of 10 volts or more. Note: If you attempt to turn the generator shaft an ...





For full article and photos see-

http://www.tongacharter.com/report-wind.htm



Note- I don't build wind generators or sell wind generators. This is a free report previously published in Tradaboat NZ.

At the bottom of the article is a link to return to this forum or hold the ctl key while you click on the link to keep the forum page open.

 

I clicked on your link and reading the modifidcation of the alternator there are a couple of things I dont follow
1/ the stack of magnets inside the rotor should surely be stacked so they all want to stay together.. ( the flat faces are N and S poles) ......this modificatdion must be inefficient as what is to stop the magnetic field going down the central shaft rather than jumping the rotor poles ...???
2/ you say you want 4 times the statar turns so use 1/4 thickness of wire .....but if you halve the diameter you will have 1/4 volume so you can get 4 times the wire on it ..explain that please ???. do you prefer star or delta winding ??

 

Pistnbroke- Thank you for reading. Your point is very observant and appreciated. The alternator modification is listed as "experimental" and in fact if anyone has successfully built a PM generator motor from an alternator and would be willing to put the plans into public domain that would be a great companion to the wind generator article.

I probably would not have bothered to post the link to the wind gen as there are many good designs on the net already, except for the plans to the wind gen blade. It's a very good one and I think worth downloading to keep on file if ever needed.

You ask about Delta to Yankee windings. I'm going from memory on this, but back in the early days of high output alts (1980's) we spent a few years rewinding every alternator we could find. (We eventually dumped the idea in lieu of the dual alts.) During that time of experminatation we found that Y configuration took more rpm's to produce amps, but produced more current at full/max rpm's. A Delta configuration produced more amps at low rpm's but had a lower top output. So, for this reason we see most high output stators to be D wound so they get a good amp output at low rpm's. It's what I would start with on a wind generator alternator modification.

So, the question I think we have on the alternator to PM generator conversion is a simple way for the DIY to build the rotor/field. Any ideas?

Thanks for asking and I hope this helps keep the discussion going.

Scott

 

experimental in this case means technically inacurate and impossible to acheive without a non magnetic rotor shaft .

I dont think posting this sort of technocrap is helpfull to anyone or your reputation.....

 

Can you provide a better design?

I'm never sure if I should continue a conversation like this. I tried to answer your question with respect and honesty. I'm going to take a leap of faith that your question is still on how to build a wind generator from scrap.

Remember this is a link to a free design with a blade drawing that took a large amount of effort to produce.

You sound like you have some knowledge in the field. Would you be willing to draw up a design on how to turn a surplus alternator into a low rpm generator and post it for the use of the Boatdesign readers.

Regards

Scott

 

I have come to the conclusion over the years that people who make errors in the basics ..like your magnets or not knowing the basics of the magnetic circuit in the alternator rotor are best avoided as there more shopistocated assumptions are usually wrong as well. Unfortunatly articles like this send people running to tear down alternators and make generators based on your ideas which will not work without a major re design and I dont think it is fair to publish technically inacurate material which does this ..

Your rotor blades look useful and easy to make ...

 

Thank you for your comments. This appears to be a forum to discuss design ideas.

Do you have an idea or a design on how to turn an alternator into a low speed PM motor?

That would be helpful.

Scott

 

yes i have a design ..took all of about 5 seconds to think up to solve the problem of the shaft providing a megnetic path for the ring magnets and in effect shorting out or shunting the magnetism ....It involves a large lump of hard polyurethane about 2 in dia, a lathe and a press operated by a brain .....

BUT why should an article posted by someone of whom I know knothing promt me to share my idea ??? Your original post strikes me as an attempt to re kindle flagging Yanama two alternator bracket sales .... Now if it was CDK /Frosty/fannie/new comer or other well know figures who had a genuine problem I would help them or even make the bits for them ..............

 

You would make parts for me Pist? Ive come over all emotional.

I--I guess I could put you on my new years list,----naaa

 

of course but they would need to be put in cold storage and shipped refrigerated ......

 

This link has been moved here-

http://yachtwork.com/report-wind.htm

Thanks

Scott

 

Ik denk dat de ontwerper gud moet zijn, dan geen probleem

 

dont encourage or rely to yachtwork he is just using boat design to get sales for his books .....

stay cool stay frosty and keep quiet and he will go away .....