I don't want to have to pay for electricity when renting an apartment, so I've looked up designs for a stationary bike electricicity generator and I don't know where to find a "permanent magnet DC motor that produces 24 volts at 600 rpm" as the site suggests, so any ideas? I've got an old factory, where wire fences are made, to scrounge through

Assuming a bike has a tire diamiter of 26 inches, and a gear ratio of 1:1, to get it spinning at 600RPM would be the same as going 46mph on a flat road. With a gear ratio of 2:1, it would be the same as going about 23mph, but twice as much force would be needed to do one full rotation.

It won't be easy to constantly go 600RPM. I'm not sure how much force would be needed to turn it over, but no matter what it won't be easy to maintain 600rpm.

got the specs on this sight http://www.humboldt.edu/~ccat/pedalp...004/index.html

but this one seems to have worked too
http://www.youtube.com/watch?v=QM8W76nGc0o
which they ran with this motor
http://www.amazon.com/gp/product/B00...SIN=B000BO3NPY
so I'm wondering what sort of machinery I could find within a fence factory that would have this sort of motor

The human body is most efficient at a cadence of 80 RPM, so figure your gearing for that.

Here's a drawing I did just now:



Let's say that the distance between each of the pedals is a foot. 6 inches out of the center of the axle are both of the pedals. The pedals are being spun at 80RPM each. Since the center of the axle is 6 times closer than the pedal, it will spin 6 times as fast. (Not sure if this is correct, I went of my logic. I'm probably wrong. Can anyone tell me if I am?)

So, the center is spinning at 480rpm. With 26" tires and a gear ratio of 1:1, at any given moment the part of the wheel that touches the road will be traveling at 37mph.

That means that, assuming that the rod connected to the motor is 1 inch in diameter, and a constant speed of 37mph is achieved by the engine (you) then the steel rod connected to the engine would be spinning at 53,472RPM.

That's not right, I know.

Hold on while I look over my maths

EDIT: I think I got the speed that the bar is spinning wrong (in MPH) which fucked up my conversion to RPM

Okay, to actually answer your question:

Take apart big machines that look like they spin stuff. Lathes, spindle winders, fans, and things like that. That's what I'd do. Just to clarify, are you sneaking into a working factory and stealing it straight up, or is it abandoned or something?

EDIT: A lot of industrial motors are 3-phase AC. There's a way to rewire them to work as generators. I'm at work right now so I can't find the bookmark, but I'll post it if I can. Otherwise just google 'wind power 3-phase rewire' or something.

There's your problem!

Couple of things to report: I've got a virtual smack in the face and realized that the center of the gears would be spinning the exact same speed as the pedals, my mistake

I also realized that the gear ratio of a typical mountain bike is 3.42:1, not 1:1. Another dumbass mistake. Hey, don't blame me I did this at 4 in the morning

So with everything sorted out, looks like the wheels will travel at 21mph at top efficiency. I'll work the rest out later, but for now it's time to go dumpster diving

Even if you go through the trouble of building something like this, you're not going to be able to generate more than 500 watts for any reasonable length of time.
That's about half the amount required to toast a piece of bread.

You realize this, right?

[quote=Sentinel;10235927]

Just to clarify, are you sneaking into a working factory and stealing it straight up, or is it abandoned or something?
/QUOTE]

My family owns it, so I was going to look around with my grandpa