[Lab] human powered art

Sat Jan 15 23:44:14 EST 2011

On Sat, Jan 15, 2011 at 08:45:46PM -0500, Darcy Whyte wrote:
> 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.
> 
> Do you think a couple of NEMA 34 motors is enough to capture energy that a
> person can generate?

I have no idea about the efficiencies of a stepper.  I'm even surprised
it would work since I didn't think the armature was magnetized.

> I think a car alternator is out since it needs electricity to generate
> electricity. I'm not sure their so efficient.

You are right on both counts.

> 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?)

Most resistive electric appliances (and microwaves) such as toasters,
kettles, toaster ovens, electric frying pans, hair dryers, etc. draw
900-1800W, which is 1 up to 2.5 HP.

> 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).
> 
> 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.
> 
> The page you made on human generators looks awesome. I'll go through those
> links and information.

I probably have some other links and information elsewhere since I have
looked this up before.

Here is one goldmine of info...  Past issues of "Home Power":
	http://tricolour.net/home_power/Home%2520Power%2520Index%2520%2523001-109.pdf
	http://tricolour.net/home_power/
Please be gentle on my bandwidth.  The first link is the index.

> On Sat, Jan 15, 2011 at 6:12 PM, Richard Guy Briggs <rgb at tricolour.net>wrote:
> > On Fri, Jan 14, 2011 at 07:14:29AM -0500, Darcy Whyte wrote:
> > > I would like to make a human powered generator for an art project.
> >
> > I've been wanting to build one for a while now...
> >
> > > I am curious if a couple of NEMA 34 motors is large enough to capture all
> > > the power that a human can generate.
> >
> > My understanding is that a stepper is not the kind of motor that can be
> > used as a generator.  Wait!  I stand corrected!
> > http://www.thebackshed.com/Windmill/assemblyMini3.asp
> >
> > What is most commonly used to generate DC is a commutated DC motor.
> >
> > A car alternator will also work.  It is an AC generator with a
> > rectifier, but they tend to be a lot less efficient.  It also needs a
> > power supply bias to get started (say, a car battery under charge) since
> > there are no permanent magnets and it uses a field coil.
> >
> > My understanding is that motors are typically 80% efficient, while
> > dynamos closer to 50%.
> >
> > Do you have a link for your NEMA 34 motor specs?  I've seen anywhere
> > from 50W up to 500, so it sounds like those might work!
> >
> > > I'm looking at a couple of applications.
> > >
> > > 1) To run a 120V toaster. I suspect this might need as many as 5 people
> > to
> > > peddle. Also to run a 60W incandescence bulb.
> >
> > A toaster is going to need 3 top athletes (400W ea) or about 8 fit
> > adults (150w ea) to run.  For kids (50w ea), it is going to be more like
> > 25...
> >
> > > 2) To charge a 12V battery.
> >
> > One will work here, it'll just take longer...
> >
> > I wanted to power a TV, or at least to power the "on" circuit.  Other
> > ideas we had was to use a human powered generator to power parade float
> > lights or moving parts.
> >
> > > I'm suspecting that a stepper motor is a good candidate to make the
> > > electricity. I think the first part of the project is to make up some
> > BOMs
> > > that show what motor to use, the RPM that it would require and parts for
> > a
> > > rectifier and whatever else is necessary to operate in these
> > applications.
> >
> > I've got lots of small ones, so I can try some tests and see.  I
> > wouldn't have thought they would work because the rotor I thought was
> > unmagnetized steel.
> >
> > > Does anybody know of any existing projects or have any recommendations?
> >
> > There are lots out there that I have tripped upon in the past...  I
> > threw together this page to summarize:
> >        http://tricolour.net/bicycle-generator.html
> >
> >
> > I just tripped on this site that may be of interest too:
> >        http://www.thebackshed.com/
> >
> >
> >        slainte mhath, RGB
> >
> > --
> > Richard Guy Briggs               --  ~\    -- ~\            <
> > hpv.tricolour.net>
> > <www.TriColour.net>                --  \___   o \@       @       Ride yer
> > bike!
> > Ottawa, ON, CANADA                  --  Lo_>__M__\\/\%__\\/\%
> > Vote! -- <greenparty.ca
> > >_____GTVS6#790__(*)__(*)________(*)(*)_________________
> >

	slainte mhath, RGB

--
Richard Guy Briggs               --  ~\    -- ~\            <hpv.tricolour.net>
<www.TriColour.net>                --  \___   o \@       @       Ride yer bike!
Ottawa, ON, CANADA                  --  Lo_>__M__\\/\%__\\/\%
Vote! -- <greenparty.ca>_____GTVS6#790__(*)__(*)________(*)(*)_________________