[Lab] human powered art
krazatchu at hotmail.com
Sat Jan 15 22:28:15 EST 2011
The magnets are going to be the single most expensive purchase in the diy windmill design...
The 3 phase design has some advantages in that you can rewire in series for a higher voltage or in parallel for more current...
You could also effectively rewire in real time but it's probably easier to just PWM the load to track the maximum power point...
If your going to run a toaster at normal cooking level, you will want to get the voltage up to 120 vac...
Anything less and it's not going to cook at a normal rate as the resistance is fixed... P= V^2 / r
You could feed an inverter at 12-14 vdc ... Or you could aim for over 120 volts ac directly from the genny and switch it down...
I suspect using an inverter will be the easier option, you should be able to find a 1500w model for $50.....
From: darcy at siteware.com
Date: Sat, 15 Jan 2011 22:10:00 -0500
Subject: Re: [Lab] human powered art
To: krazatchu at hotmail.com
Now we're talking that's affordable. In this config: http://www.econvergence.net/electro.htm
It might be okay.
Here's a bigger one I just came across.
But your 300 RPM one takes the cake. Catch is I'd have to spend more time making it. I will look at that instructable and see how much it would cost....
On Sat, Jan 15, 2011 at 10:02 PM, krazatchu . <krazatchu at hotmail.com> wrote:
This is a better deal...
If the motor is rated for 24 volts and 2600rpm, then you will have to turn it at 2600rpm to get 24volts...
This is more work http://www.instructables.com/id/DIY-1000-watt-wind-turbine/
But the cut in, where it starts producing will be around 300 rpm..
I think with your cnc mill, you could make it quite well...
From: darcy at siteware.com
Date: Sat, 15 Jan 2011 21:52:25 -0500
To: rgb at tricolour.net
CC: lab at artengine.ca
Subject: Re: [Lab] human powered art
I found a site that has a motor like it. http://www.thebackshed.com/Windmill/Oatley-windmill.asp
It's a windmill site.
They're calling it an Oakley DC motor. Nothing shows for that in ebay though.
On Sat, Jan 15, 2011 at 9:37 PM, Darcy Whyte <darcy at siteware.com> wrote:
I'm going through the pages on your page on Human Power. There are a couple of good candidates there.
Looks a little pricey at well over 200 bucks.
This cool pedal generator in the picture at http://mambohead.com/2011/01/using-a-stepper-motor-as-a-generator/ is 400 bucks for everything. I think the thing to do is figure out what motor they are using as a generator on that one.
Does anybody know?
On Sat, Jan 15, 2011 at 8:55 PM, Darcy Whyte <darcy at siteware.com> wrote:
I guess another way to look at it is if I need 1000W to make toast. And it takes 5m to make the toast. If we can get 50W out of a person, then they'd have to peddle for 15m to charge a battery, then they could make the toast in 5m. So it would take 20m to make the toast. (Assuming we've got a pretty efficient generator and battery).
But then we don't feel the real load of making toast since we've spread it out over 15m. I wanted to make the power in real time. I imagined that a person would guess (wrongly) that they could turn the generator and make toast easily. But when they try it they will be surprised that they can't sustain since the toaster draws too much current. So then they'd get their friends to help gang up on the machine.
So I was thinking of having some sort of spool with cable on it and people could row (turning the spool), or even harness the cable to their hip and run out for 20 feet, then return and do it again. If there were a long enough spool so lots of people could be doing this action, then a team of people could probably make the toast.
I've got some interesting ideas of how to have people turn the generator but I want to start with having one that's efficient and the right size.
On Sat, Jan 15, 2011 at 8:45 PM, Darcy Whyte <darcy at siteware.com> 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 think a car alternator is out since it needs electricity to generate electricity. I'm not sure their so efficient.
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?)
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.
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!
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
> 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
> 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:
I just tripped on this site that may be of interest too:
slainte mhath, RGB
Richard Guy Briggs -- ~\ -- ~\ <hpv.tricolour.net>
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