Wind Turbine. ?

[Dave Fowler]

Hi all. I plan on building a small wind turbine to charge the battery pack.
Using a 3 HP PM DC motor 25 amp- 0 to 4000 rpm.
Question.. Is this a suitable generator?
If so how do I control the speed and voltage.
Wind gust to day from 40 to 100 kmh.
Need advice All comments appreciated.
Thanks Dave F.

[Steven Fahey]

Hi,
DC motors are sometimes good candidates for wind turbine generators, but some planning in advance of buying is necessary. Your motor seems to have a 4000 RPM rating. That's way too fast for a wind turbine - small ones may go up to 1000 RPM in the teeth of a storm, and the larger they get the slower they should turn.

Well it may not be totally hopeless. What is the voltage rating of the motor? What is the voltage of your battery set? If, for example, you have 12V batteries, and this motor's rated voltage is 120V, then the math goes like this:

120V/12V = 10

4000 RPM / 10 = 400 RPM

It may be possible to use the motor with a 12V battery bank if the original voltage rating of the motor is high enough. If it's a 90V motor, you're pretty much out of the ball-part, likewise if your batteries are set up for 24V or more.

[Dan Lenox]

Dave,

A good working example is the Breezy from Prarie Wind Turbines (I have no association with them).

They used a 5hp Nord 1700rpm motor that had a built in gear reduction, this reduction works in reverse when using as wind turbine so it actually gears the motor up. You will loose some percentage of power to the reduction but it is the only way to get the motor up to speed.

I purchased the plan set and the plans are a bit rough, but still good for reference.

So the short answer to your question is yes, it can work, but the devil is in the details.

Dan Lenox