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Forum Index : Electronics : dc treadmill motor
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| radman Newbie  Joined: 29/11/2011 Location: United StatesPosts: 12 |
Hi all, this is my first post on this forum. I am rebuilding a wind turbine and I need some info on motor winding's. I started out with a 100 volt , 5100 rpm motor and I used a pulley system to to try to get enough rpm to make juice. I do not have strong enough winds to turn it with that much loss of energy. The motor had 17 turns of wire of 20 gauge wire I think there was enough room to have maybe 10 more turns with the same gauge wire. So this is already pretty thin wire, but I need to bring the rpm down to under 300 at around 14 volts. Before I took the motor down I measured its output. It made about 13.5 volts at 750 and 24 at 1300 rpm, as fast as my drill would turn. The plate does not say what amps it draws. So my question is how much can I step the wire down without getting to low amps? 24 gauge is pretty thin and I worry that I will smoke it. Input please, Radman |
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Hi Radman 25 guage is a big step from 20 guage wire. 20 guage AWG is 0.81mm diameter, 0.52mm2. 25 guage AWG is 0.45mm diameter, 0.16mm2. http://www.engineeringtoolbox.com/awg-wire-gauge-d_731.html So 25 guage would pass about 1/4 the current of 20 guage, thats a big loss. But you can fit 3 to 4 turns of 25 guage in the space of a single 20 guage wire, so you gain volts. If you were making 13.5 at 750rpm with 20 guage, then that rpm would be closer to 250 with 25 guage. At the end of the day, the 20 guage wire isn't working for you, but the 25 guage would. The power wont be great, maybe 30 or so watts . But at the moment its not making any power, so you do gain something. A lot of work though. You may be better off looking for an alternative motor. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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MrDelanco Senior Member  Joined: 12/11/2011 Location: United StatesPosts: 101 |
Do you have any photos of the motor you have taken apart ? MrDelanco:Project Videos It is not only too know what it does but to understand how it does what it does. |
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| radman Newbie Joined: 29/11/2011 Location: United StatesPosts: 12 |
This is the armature i am working on. Thanks for the reply, what would the outcome be if I could add say 10 turns with 20 gauge for a total of 27? Radman 
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
What we need to work out is volts per turn. At 750 RPM it reached 13.5 volts with 17 turns, so thats 13.5 / 17 = 0.79 volts per turn at 750rpm. If you can fit 27 turns, then 27 X 0.79 = 21.4 volts at 750 rpm. Then divide it down to a lower rpm. 750rpm / 21.4v X 13.5v = 473rpm. So you will need 473rpm to reach 13.5 volts. Still very high. What about a slightly smaller wire? If you can fit 40 turns instead of 27, the rpm drops down to 326, which could work. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| radman Newbie Joined: 29/11/2011 Location: United StatesPosts: 12 |
Hi Glen, I want to thank you for the help with this. You mentioned 25 gauge in your first post, I would think I should be able to wind 40 turn's with that, based on what you see in the pic. how much wire should I buy? There is a coating on the ends of stack and some of it broke away taking the wire off. Can I just lay a bead of epoxy down over this area? Or is there some other goo that is needed? Thanks, Radman |
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| MrDelanco Senior Member Joined: 12/11/2011 Location: United StatesPosts: 101 |
More research. If you want to change the motor speed (number of poles), additional conditions must be met, otherwise undesirable effects: noise, clogging and cusp, may occur. Therefore, in some cases, such redesign is impossible to achieve. armature winding AC Generator Construction - The Alternator Stator MrDelanco:Project Videos It is not only too know what it does but to understand how it does what it does. |
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