[Lab] human powered art

[Richard Guy Briggs]

On Mon, Jan 17, 2011 at 12:28:46PM -0500, Andrew Plumb wrote:
> Hey Richard,

Hi Andrew,

> Since you have a few steppers kicking around, something to try is
> wiring them up in parallel.  If you turn one, the other may turn
> in-step.

Neato!  I finally tried this today.  It works!  I would have expected
two brushed DC motors to work no problem with some inefficiency, but
wouldn't have expected this to work.  It does, and for two identical
motors, at the same speed.  It tends to work better, not surprisingly,
with a higher voltage motor driving a lower voltage one.  The step size
also has some effect.  The motors with lower step size are easier to
drive.  I've got several pairs working, but their working range is
somewhat limited.  They are also sensitive to acceleration.  If you
don't accellerate them too fast, the other motor is able to keep up
better.  They are after all synchronous motors.

> Not sure what might happen if you wired three up in parallel, or maybe
> in a triangular arrangement with one phase wired to each neighbour.
> Get two people to crank steppers with/against each other, attach a
> fly-wheel to the third stepper and see what happens.

Three in parallel should work too, but depends on the efficiency...

As far as three-phase goes, I don't see why that couldn't work, but for
efficiency issues.

The obvious happens if you try to turn two connected to each other in
opposite directions.

> Andrew
> 
> On 2011-01-16, at 8:38 PM, Richard Guy Briggs wrote:
> 
> > On Sat, Jan 15, 2011 at 06:12:24PM -0500, Richard Guy Briggs 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 am curious if a couple of NEMA 34 motors is large enough to capture all
> >>> the power that a human can generate.
> > 
> >> 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 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.
> > 
> > I now understand that NEMA 34 is a mounting plate standard.
> > 
> > So, looking through my box, I have one NEMA 34 motor and four NEMA 23,
> > plus about eight NEMA 17 or smaller as well as a bunch of other smaller
> > assorted steppers.
> > 
> > The NEMA 34 is a Matsushita 1HHS-486CS, 6V, 2.2ohm, 1.8 deg/step 6-wire
> > unipolar.  I can't find any info about it on the net.  My guess is it
> > its max rating is around 36W, maybe double that depending on how they
> > rate them.
> > 
> > Hooking up a bridge rectifier across each coil, using a cordless drill,
> > I was able to get .5A short circuit and beyond 12v out of it open
> > circuit.  Using various loads, I think I was able to get as much as 12W
> > out of it.  It wasn't exhaustive, but I think that was somewhere near
> > the peak.  I may have been able to get more with a higher speed.
> > 
> > One of the NEMA 23 motors is a Matsushita 1HHS-457CH 24V, 26ohm,
> > 1.8deg/step 6-wire unipolar.  Didn't find anything on it either.  Again
> > my guess is 48 or maybe 96W.
> > 
> > Short: 0.16A, Open: 170V  Most I was able to get was about 8 Watts out
> > of it.
> > 
> > These motors look pretty underpowered compared with some of the specs
> > I've seen on the net...  This isn't surprising since I think these are
> > 20 years old.
> > 
> > Darcy, do you have any part numbers or specs for your steppers?
> > 
> > 
> >> 	slainte mhath, RGB
> > 
> > 	slainte mhath, RGB
> > 
> > --
> > Richard Guy Briggs               --  ~\    -- ~\            <hpv.tricolour.net>
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> 

	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__(*)__(*)________(*)(*)_________________