<div><div>Yeah, I think a stepper can be a good generator. But the problem I'm trying to solve is what size of stepper or electric motor would make a good generator for capturing electricity from a human. Apparently a human can average about .1hp. But can put out more power in bursts. So I was figuring that stepper might be too small. </div>
<div><br></div><div>Do you think a couple of NEMA 34 motors is enough to capture energy that a person can generate?</div><div><br></div><div>I think a car alternator is out since it needs electricity to generate electricity. I'm not sure their so efficient.</div>
<div><br></div><div>Yeah, I figured for the toaster application we'd need more than a hp. I'm wondering if a NEMA 34 would be enough. Or perhaps a team of them (what size team?)</div></div><div><br></div><div>Your numbers agree with mine on the number of people it would take. And that's part of the message in this art piece. The average person doesn't have a sense of how much electricity we use in terms of the work it's equivalent to (in terms we understand).</div>
<div><br></div>So if it turns out it's 2 NEMA-34s to extract power from a human, I may need to look at about 10 of them in the toaster application. (So people can team up to push the generators to make the toast. <div>
<br></div><div>The page you made on human generators looks awesome. I'll go through those links and information.</div><div><br></div><div><br>
<br><br><div class="gmail_quote">On Sat, Jan 15, 2011 at 6:12 PM, Richard Guy Briggs <span dir="ltr"><<a href="mailto:rgb@tricolour.net">rgb@tricolour.net</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
<div class="im">On Fri, Jan 14, 2011 at 07:14:29AM -0500, Darcy Whyte wrote:<br>
> I would like to make a human powered generator for an art project.<br>
<br>
</div>I've been wanting to build one for a while now...<br>
<div class="im"><br>
> I am curious if a couple of NEMA 34 motors is large enough to capture all<br>
> the power that a human can generate.<br>
<br>
</div>My understanding is that a stepper is not the kind of motor that can be<br>
used as a generator. Wait! I stand corrected!<br>
<a href="http://www.thebackshed.com/Windmill/assemblyMini3.asp" target="_blank">http://www.thebackshed.com/Windmill/assemblyMini3.asp</a><br>
<br>
What is most commonly used to generate DC is a commutated DC motor.<br>
<br>
A car alternator will also work. It is an AC generator with a<br>
rectifier, but they tend to be a lot less efficient. It also needs a<br>
power supply bias to get started (say, a car battery under charge) since<br>
there are no permanent magnets and it uses a field coil.<br>
<br>
My understanding is that motors are typically 80% efficient, while<br>
dynamos closer to 50%.<br>
<br>
Do you have a link for your NEMA 34 motor specs? I've seen anywhere<br>
from 50W up to 500, so it sounds like those might work!<br>
<div class="im"><br>
> I'm looking at a couple of applications.<br>
><br>
> 1) To run a 120V toaster. I suspect this might need as many as 5 people to<br>
> peddle. Also to run a 60W incandescence bulb.<br>
<br>
</div>A toaster is going to need 3 top athletes (400W ea) or about 8 fit<br>
adults (150w ea) to run. For kids (50w ea), it is going to be more like<br>
25...<br>
<div class="im"><br>
> 2) To charge a 12V battery.<br>
<br>
</div>One will work here, it'll just take longer...<br>
<br>
I wanted to power a TV, or at least to power the "on" circuit. Other<br>
ideas we had was to use a human powered generator to power parade float<br>
lights or moving parts.<br>
<div class="im"><br>
> I'm suspecting that a stepper motor is a good candidate to make the<br>
> electricity. I think the first part of the project is to make up some BOMs<br>
> that show what motor to use, the RPM that it would require and parts for a<br>
> rectifier and whatever else is necessary to operate in these applications.<br>
<br>
</div>I've got lots of small ones, so I can try some tests and see. I<br>
wouldn't have thought they would work because the rotor I thought was<br>
unmagnetized steel.<br>
<div class="im"><br>
> Does anybody know of any existing projects or have any recommendations?<br>
<br>
</div>There are lots out there that I have tripped upon in the past... I<br>
threw together this page to summarize:<br>
<a href="http://tricolour.net/bicycle-generator.html" target="_blank">http://tricolour.net/bicycle-generator.html</a><br>
<br>
<br>
I just tripped on this site that may be of interest too:<br>
<a href="http://www.thebackshed.com/" target="_blank">http://www.thebackshed.com/</a><br>
<br>
<br>
slainte mhath, RGB<br>
<font color="#888888"><br>
--<br>
Richard Guy Briggs -- ~\ -- ~\ <<a href="http://hpv.tricolour.net" target="_blank">hpv.tricolour.net</a>><br>
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