my first wind turbine build

[roddas]

hi all this is my first wind turbine build so looking for any advise you may have, im using a pacific scientific treadmill motor with the following specs it is 1.5hp 2600rpm @ 180volt dc and 5amp,im using a 3 blade set with a 51inch sweep
 

[sean_ork]

you'll need to spin that very quickly - so ponder removing 1 of the blades and making a new hub

also expect to replace the blades fairly regularly as they will flex at the root where they meet the hub, and due to work hardening will crack

also, make sure the point of balance is directly under the yaw point

[roddas]

hi thanks for the reply I should have also mentioned in my first post that I have tested it out the garden and made around 60 volts I can get around 20 volts spinning by hand,
as for the blades they are made of aircraft grade aluminium witch I bought and there bolted to a steel hub, the biggest problem im having is how to slow it down because even under load it still spins very fast and I need to find a way to slow it down in high winds

[Frank S]

TO help stiffen up the blades you might consider laminating a couple more strips of aluminum to the blades effectively extending the hub this way.
 As for over speed a mill of 51" diameter should be able to spin really fast I would think that something in the range of 6 to 800 RPM would be fine though possibly with some noise

[sean_ork]

making 60v is fine - but what does its produce when it has a proper load connected - such as a 12V battery

the voltage will be clamped by the battery - the amount of charging current produced will be the true gauge of success

 

[roddas]

hi again, well ive had it hooked to 2 car batteries wired 24volt and the multi meter and I got a average of 25 to 30volt when the wind picked up a bit, ill know a bit more when I get back from holiday as I will be doing some more testing with it a bit higher up as last test it was only about 2 meters off the ground,
I will also be having a look at the blades again as I was advised to maybe put a couple of re-enforcing strips on witch makes sense

[sean_ork]

30v ?

[fabricator]

Aluminum blades whether 3003 or 6061T6 will eventually work harden at the attachment point and break guaranteed, especially at the speed that mill is spinning.

[Bruce S]

There are a few things you can do to tell how well the mill is working.
First things get a couple discharged batteries, or use the ones you have to charge other "stuff".
Grab a meter or two if you have them, hook one up for measuring current, the other voltage.
This will tell you the voltage and current going into the discharged batteries.
IF you're hitting 30Vdc steady; then lengthening the blades will slow it down. A sweep of only 52 inches is pretty short >5 feet.
As others have said, and since Fab is a metal person he kinda knows these things. Now would be a good time to possibly look into steel or wooden blades?
The speed is on track for the RPMs your seeing, 30Vdc is about 420 RPMs unloaded.
Cheers
Bruce S

[sean_ork]

seeing ''an average of 25 to 30 volt when the wind picked up a bit'' sounds to me as if the batteries are dead, presenting a minimal load, hence you being able to see the voltage rise and fall

where are you measuring that voltage ?

is the output wired directly across the battery terminals ?

[roddas]

hi I took the meter reading from the wires out of the turbine before they get to the batteries and yes the batts were a bit flat but did noticeably take a charge, now im back off holiday I will be doing some more testing and will let you know how they go, I will also be trying some different length blades to