I only get 3.5v max.

[befnme]

I built a wind generator. I can only get 3.5 volts max. Even in a good gust. The prop is turning like mad but just cant produce. I built it like this one :

http://duggmirror.com/environment/Build_your_own_backyard_wind_turbine_Cut_your_electric_bills/

this is the motor I used :

specs are:

New, McMillan Electric model S335782768 permanent magnet motor . Heavy (3 lb.) cast iron fan/flywheel threaded onto motor shaft has six-groove pulley on end for a serpentine belt. Flywheel can be removed but the motor will require an external cooling source for prolonged use as a motor. CCW rotation recommended to keep flywheel from unthreading, motor itself is reversible. Lead end of rotor is tapped for a M4 left-hand bolt. 14" long leads with female spade terminals. Would make an excellent DC generator. Test has shown this motor/generator will generate 12 VDC at 490 RPM and 24 VDC at 980 RPM. When geared to 4900 RPM to a wind generator turbine this generator will give you 120 VDC. Specification for the motor generator by manufacturer is as shown below. The hub (fan wheel) of this motor can easily be used with home made fan blades (PVC pipes). As a generator the fan wheel is not necessary to keep the motor generator cool at 8 amps and 120 VDC

 3/4 HP

130 VDC

Rated to 8 Amps

5,100 RPM @ no load

Rotation reversible *(see paragraph above)

Open housing

5" dia. fan/flywheel with 36 mm (1.41") dia. 6-groove pulley

Treadmill duty (2-4 hours) *(see paragraph above)

Two 5/16"-24 holes in side of housing on 3-5/8" centers

Shaft: 17 mm dia. x 1-1/8" long w/ 1/2"-13 x 7/8" long RH threaded end

Size 3-1/4" dia. x 7-1/8" long W/O face plate

4-1/2" dia. x 5/64" thick face plate

For the blades I used 6" sch.40 pvc.cut 36" long each. I balanced them as good as posible.rounded the leading edge and ground the trailing edge sharp. What else can I do? I have it mounted on my house for a total of about 30'tall.

[befnme]

I forgot to mention. This is my hub:

[ghurd]

The blades are too long. Maybe try them at 24" each.

There are 3 blades?  Not 6.

G-

[befnme]

Yes only 3 blades. I thought more blades meant more torque but slower speeds. If I cut my blades do I reshape them back to 1.5" at the end, or leave it as wide as it will be?

[ghurd]

Three blades is good.  The hub made me wonder.

Reshape them.  Cutting them off doesn't work out well for me.

Zub-Woofer's...

http://www.fieldlines.com/story/2003/11/11/172721/53

[befnme]

Thanks ghurd, I will give it a shot.

[Jerry]

Been there done that. Keep an Eye out for simular motors at 2,000 rpm. This rpm range is too high.

                         JK TAS Jerry

 

[befnme]

I just bought an AMETEK motor I think it would be better.

[Norm]

  Judging by the data, you get about 1 volt per

50 rpm so when you get 3.5 volts that's 175 rpm

so the phrase 'spinning like mad' isn't too

accurate. LOL !

  Seriously you're going to have to get a much

faster set of blades or gear up, also nothing

wrong with thinking 6 volt charging system...

keeping in mind....line loss, so heavier wire

and battery at the bottom of the tower.

  Welcome to the world of reality.

   Still....it's a lot of fun !

[CmeBREW]

You can always use that DC motor for a very nice Box/floor/ceiling fan. I have the same motor myself. Hooked to a 12v battery it goes about 600rpm and only takes about 10watts if I recall. Just make a 24" diam. fan blades on it.  Thats over 1000 percent more efficient than a typical box fan.

The Ametek is much better for a windmill.

[befnme]

ok i trimmed my blades to 24" and now they wont even budge. same amount of wind where the 36" blades were atleast getting a descent rpm. should i now try 48" or 60" blades?

[ghurd]

Don't confuse spinning with power.

If they are longer, then they are slower, and cut-in voltage will never be reached.

Like Jerry said, it's going to take some serious RPM for cut-in.

Shorter blades are going to start harder, but it shouldn't be That much harder (with PVC blades).

Does it still spin by hand as easy as it did before?  If not, maybe a wiring problem.

Could simply be lack of enough wind.  There is a huge difference between 6MPH wind and 9MPH wind.

As Norm pointed out, 175 RPM isn't very fast, meaning maybe the wind wasn't/isn't so strong.

Quick math?  It is going to take twice the wind it had with 6' dia blades to get to charging voltage with 4' dia blades.  It would take three times that wind with the 6' dia blades.

I wouldn't worry if it doesn't start turning until the wind is a bit stronger. Once it starts turning it should pick up speed pretty fast.

Not the best motor, but it is 90% finished.  Might as well fly it until something better is in hand.

G-

[befnme]

Thanx, It does spin just as eay by hand. I went into town and when I came back it had moved position but can't tell id if spun the blades. hopefully my ametek gets here quickly.

[Focus]

I'm fairly new to all this but it seems to me you need to gear this motor to your blades. The motor you have should do fine however you do need to use larger blades and gear it 5 to 1 or something similar. You'll need to play with it a little to get the right gearing and blade size. You can do this with pulleys and belts or gears & chains. You do lose a little power using these but it's better then what you have now, right?

-

[interplain]

Hello, have you any new news on this motor. i have the same one and like you dont see much power being produced. I have got 6x2foot blades and it goes like mad. but i think the only way i can improve is to gear it up. I was looking at a 10-1 ratio. this would help i think. But the Guy on ebay that sells these doesnt know what he is selling. He just knows how to write BS. This mcmillan electric motor s3357B2768 is big heavy and hard to turn by hand. I think the most we are going to get out of this about 10v, on a good day.. It was claimed on the page as being like a Ametek 99, Rubbish. I knew it was going to be a dispointment when i first held it. But like many of the Ebay motors they are junk being sold to people with great expectations of being able to make electric. I would like to hear from any other person that was conned into this motor..