Sometimes A Guy Just Has To Say ""What the ????!" Make your move!

[LowGear]

I bought a Windy Boy 7000 to grid tie my Witte.  The plan is to get a three phase PM generator and rectify it. 

OK!  Its not overly efficient but in War there are greater objectives that cost effectivity or ROI.  Remember that those we are fighting are laying waste to their countries in numbers that would numb the average capitalist and stop the heart of the true environmentalist.  So a couple of percent here and may one or two over there is really nothing.

Moving on:

I'm looking for recommendations for a low speed three phase PM generator. 

I am near totally ignorant of rectifiers.  Got a drawing of a butt-kicker?

And how do I stop this gorilla from socking too much power to the Windy Boy (300 - 600 volts with a maximum of 7450 watts)?

Casey

[mike90045]

Homebrew Listeroid Back up Charger
  Just change out the Witte for the Listeroid

http://otherpower.com/listeraxialflux.shtml    covers rectifiers and such

Or do you want a store bought one ??

[sailawayrb]

PMG...build or buy?  If buy, you might want to look at these:

http://www.ginlong.com/wind-turbine-pmg-pma-permanent-magnet-generator-alternator-GL-PMG-1800.htm

Air is low density relative to water, so you will need a lot it to generate usable power.

Bob B.

[sailawayrb]

How a rectifier works:

http://en.wikipedia.org/wiki/Rectifier

Bob B.

[admin]

is there a special reason you have to go with a pm unit?

why not a standard wound field unit?

bob g

[LowGear]

PMG...build or buy?  If buy, you might want to look at these:

Can these Ginlongs be belt driven?  The person that sold me the inverter recommended the Ginlong slow speed PM generator as well.    I'm kind of hoping for something with a brand name more like Yankee Doodle or Southern Gentleman.  The Witte really likes about 800 RPM and those 25 inch flywheels do not lend themselves to slow speed devices.  Depending on what bob g. educates me to; I may be looking for one of the 3 phase units that came with some Wittes from the factory.  I'm after three phase for the cleaner DC but that may be a delusion as well.

Or do you want a store bought one ??

When it comes down to brass tacks I'd have to hire most all of the work out.  I'm not a machinist and simply don't operate at the quality level of the Otherpower link or many of the masters that help us others on this website.  I may get crazy and try to get this thing licensed so factory stuff might make that part easier.

is there a special reason you have to go with a pm unit?

I'm so glad someone asked this question.  I don't know.  They're quieter?  More reliable?  More efficient?  Last longer?  The tempest in my tea pot?

I do vow to get off my ass and read both the wikipedia and Otherpower documents.

SMA strongly suggests to come up with a good clean 350 to 450 volts of DC and to have an absorption resister (?) or gizmo for when the Windy Boy falls off grid tie.

An open mind is a terrible thing to waste.

Casey

[sailawayrb]

PMGs can be belt driven just like anything else.  Of course, it would be better to select a PMG that will produce the power you need at the RPM (or RPM range) you have and avoid pulleys and gears completely.  One can design a PMG to do this and also achieve an efficiency in 90-95% range.  PMG are popular for wind turbines largely because they are very efficient, are a relatively simple design and hence reliable (i.e., easy to manufacture and less maintenance...the latter being especially important when located high up on a tower), and can directly produce power over the wide range of RPM that a wind turbine will experience.  PMGs can also be shorted to provide braking when needed.  PMGs cost more than conventional, so one needs to consider that too.  However, if you have the time and the skills, PMGs can also be homebuilt for little cost.  I attached some PDFs you might find useful.

Bob B.

[sailawayrb]

Some more PDFs...

And only use nickel-plated NdFeB (Neodymium-Iron-Boron) or Samarium-Cobolt (SmCo) PMs or your PMs will turn back into less than rare earth after a few years of operating even in air that you consider to be dry.

Bob B.

[LowGear]

I was just out at the Witte and there really isn't an easy answer for another pulley.  That is any easier than attaching a disk brake rotor.  Of course there is the big question.  If they're kinda easy how come there aren't folks lined up with their workshops making these units?  I do know a guy with a great machine shop out back.  He's always looking for a challenge. 

The 18 permanent magnet set might be the easy part.  I wonder how you put the second rotor on the axle? 

I wish I could read good.  The theoretical stuff looked really challenging or is threatening the more correct word?  It looks like the voltage is a combination of # of winds through the magnets and rotation speed.  I wonder who I'd contact to find out the formula for 350 volts at 700 RPM. 

The little gray cells are stewing.  You do not have a fish on but the line is twitching around.

Casey



 

[LowGear]

Hi Bob B.

The Design PDF is only two pages of many.  Any idea how I'd get the rest.

Casey

[sailawayrb]

You would have to subscribe to receive the rest.  I attached another PDF that is complete that does a nice job of laying out all the steps associated with home brewing a PMG.  One may need to invest a significant amount of time to become competent with the design and construction aspects of home brewing a PMG.  Time being money means one has to consider that in the buy/build decision too.  I personally believe PMGs are the way to go for wind/hydro but there are always many ways to do something and the way you choose if often dictated by your individual circumstances/preferences/situation.

Bob B.

[LowGear]

Hey!  This looks pretty darned complicated to me that's once I get the right design.

Casey