Hello there, I just took out the motor from an old washing machine, but it seems too weak...

/watch?v=I4TrDFdxbj8

Isn't a washing machine motor AC? If I'm not mistaken, you would have to rectify the output to create DC. You may also have to energize the field coil to get current out. (I may be wrong - I'm rusty on AC motors.)

I used a DC permanent magnet motor. Much easier to work with.

Yes it is AC, 120 W. It only gave some feedback when I measured it with the 20 V DC range of the mmeter. (I`m pretty green when it comes to el. engineering)

If I continue working on this (rectifying it, etc...) could I make it generate close to 40 W power?

See:
Electric generator - Wikipedia, the free encyclopedia

Read about Alternator & Excitation.

It seems like you need two independent windings to make power without using permanent magnets.

http://t3.gstatic.com/images?q=tbn:A...YUJPhj35ZonJoA


A DC motor is also a DC generator and would be the best way to go..
http://hsc.csu.edu.au/physics/core/m...eneratorDC.gif

The closest thing I found on YT matching my generator was some guy`s AC ceiling fan motor (his - 60W, mine 120W). which he converted to DC with spinning permanent magnets around.

What kind of rating should those magnets have?
What kind of diodes should I use for the rectifier?

Inside the junk of the washing machine I found 6 mf, 600 V capacitor, I`m going to use that to smoothen the dc voltage.

That's called a Starter Cap, IIRC..
I think it would take a lot of work to convert a washer motor into a generator.

I once salvaged a washer motor. I looked at the wiring diagram and found it had two speeds.
I used it to power a dual-speed drill press for about 10 years. Very useful and reliable motor. People use washer motors to power all sorts of shop tools.
When I replaced my DIY drill press with a Chinese drill-mill, I dumped the old one
on the curb and it was gone within minutes. :)
But, when I looked at my new drill-mill, the motor looked identical! (My Chinese band saw has the same motor too)!


There seems to be a lot of people using DC generators on bikes..

Low-tech Magazine: Bike powered electricity generators are not sustainable


If your motor is like this one, Induction Motor How it works - YouTube
Then you would need to remove the rotor and replace it with a spinning PM..
Seems like a lot of work to me..

Ok, for a good motor to turn into a generator (for this application), a couple of generic motor types come to mind:

simple, permanent magnet type:

1. Drive motor from an old treadmill
2. Heater blower or windshield wiper motor from car or truck
3. Power wheels or electric scooter drive motor

More efficient, more complicated, brushless DC motors:
1. Laser printer or copier drive motor
2. ebay "servo motor", VCR capstan motor
3. More complicated, but cheaper hacks(ceiling fan, dishwasher,direct-drive clothes washer, etc.)of AC motors
4. Any industrial 3-phase synchronous motor

The items towards the top of the list are pretty much plug-and-play devices. As you go further down the list, more and more support circuitry is needed, or you must modify the motor to make it a generator, or both. The payoff for complexity is smoother operation over a wider rpm range and/or higher efficiency.

Gener,
Is this your video?

This setup uses the drive motor out of a Fisher and Paykel washer. It looks to be a brushless-DC-type motor, with over a dozen poles and permanent magnets. Nothing like the run-of-the mill induction motors found in most American designs.

A permanent magnet alternator (not most automotive alternators) is ideal. I got mine at a surplus store many years ago (I think it was intended for wind power, got it at some crazy low price like $15), boosted the efficiency by swapping the ordinary diodes for some Schottkys out of old PC power supplies. Synchronous rectification would be even more efficient but orders of magnitude more complex.

If the load is 120V, a high voltage alternator would make more sense. Twibright Exciter If the load is mechanical in nature, a direct mechanical connection (if you can match it up well enough) would be best although that's often not possible. But for low voltage loads like electronics, a low voltage alternator makes the most sense.

Something else to consider is MPPT. Like solar and wind, you have to match the effective source impedance for best efficiency. But neither solar nor wind MPPT controllers would work with a bicycle since the source characteristics are different. DIY is really the only option there. I had to do it as part of my senior design project (along with the grid tie inverter), but it was very difficult to make an algorithm that remained stable over a wide range of inputs. For example, my first implementation (try to hold input voltage at about 16V or so, but decrease the limit down to 10V in order to hold a 3A minimum current) worked great when I tested it, but oscillated wildly when my friend Sarah tested it.

I like building with available parts, so when I needed an exercycle, I made a 2 X 4 into a stand that barely lifts the back wheel on my regular bike, supported by the chainstays. A strap over the carrier, tightened with wedges, keeps it secure. Hinged to this base is an arm with the heater blower motor from a car, driven by a small roller that is spun by the wheel. A bungee cord supplies the force for traction. A motley collection of 12V lights and accessories provides the ultimate resistance. I turned the roller from plywood using a disk sander to true it up, with the motor energized as such one last time.
I have found that I get a better workout listing to lively music than watching movies, although I didn't try "Breaking Away."