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Forum Index : Windmills : Treadmill Motor Info
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AtomicDave Newbie  Joined: 19/04/2011 Location: United StatesPosts: 2 |
Hello, I am new to this type of stuff. I recently found a nice working motor from a treadmill and was wondering if it would be a good one to use to build a windmill. Here are the specs from the plate. Treadmill: Precor M9.17si 2 Horse Power, 120 volts DC, 17.3 Amps, 4800 RPM, Continuous Duty 30 Years of Graphic Art www.dskdesigns.net 626-667-7817 |
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Hi Dave OK, its RPM might be a bit high. A typical windmill is good for 500 RPM, give or take a couple 100, on a windy day. If we take your treadmill, rated at 120v 4800rpm, and divide that down, we get 12v at 480rpm. That means it wont start charging a 12v battery until its spinning at over 500 rpm. Thats OK if your in a windy location, but for most of us its not going to work very well. But you need to do some tests before you give up on it. Some motors perform better at low RPM, so it might start charging a 12v battery at something like 300 RPM, which is not too bad 
Do you have access to a lathe, or some way to spin the motor at 300 to 500 rpm? What you need to find is its cut in RPM, the RPM where its output voltage goes over 12v. Also, more helpful is the RPM where its voltage goes over 13.5, the charging voltage of a typical lead acid battery. Thinking more about it, I've seen a few old windmills lately that use a gear box to step up the RPM. Gear boxes are generally frowned upon in a windmill, but I think they deserve a better rap, Dunlite turbines have been using gearboxes for decades. A gearbox from a angle grinder will step up the RPM 3 to 4 times, so a larger turbine running at 200rpm will drive a treadmill motor at 600 to 800rpm. But do a RPM test first, you might find this motor is OK as is. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| AtomicDave Newbie Joined: 19/04/2011 Location: United StatesPosts: 2 |
Thanks Glen for this helpful information. I'll try doing a test. I played with it a bit putting a meter on it and hand spun it. It will do 5 volts with just a hand spin. So maybe it might do well. I'm still researching it all. Thanks again. 30 Years of Graphic Art www.dskdesigns.net 626-667-7817 |
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