question on DIY generator

[coolwaters]

does the wires that are wrapped around need to be insulated? or can they be bare?

 

[matrixshaman]

Insulated in some way. Many coils and generators use an enamel coating on the wire which is a very thin insulator. But if they were bare and in contact with each other it would be seen as one big chunk of copper by most any circuit.

 

[electromage]

Are you talking about winding your own armatures? If so, you'll need to use magnet wire. It's insulated with a very thin enamel that is designed to withstand high heat.

 

[coolwaters]

is having thicker wires better?

im trying to drive some LEDs.

 

[markus_i]

Depends.
+ Thicker wires will give less ohmic internal resistance to the generator
- thicker wires mean less windings in a given volume (which is usually the limiting factor)
- thicker wires mean more copper (= more expensive) for the same number of windings

Bye
Markus

 

[Cemoi]

Once you are done winding, how do you protect the transformer and prevent the wires from unwinding: heat-shrink tubing?

 

[turbodog]

Varnish. Dip the whole thing in varnish. Then bake it in an oven to cure the varnish. It will lock the windings in place, preventing movement from vibration. If not, normal vibration will cause the wires to rub through their insulation.

I used to rewind electric motors (all sizes) for a living.

 

[n4zou]

Why are you attempting to build your own dynamo? A bottle type dynamo is less expensive than anything you could build yourself. It's perfect for driving LED's as well.
http://pilom.com/BicycleElectronics/BicycleElectronics.htm

If you just must build something yourself use a stepper motor from an old printer.
http://www.instructables.com/id/Bike-Generator/

 

[coolwaters]

wow thats thinking outside the box.. i was planning on adding the motor on the bike wheel.

i guess thats more efficient.


so basically thinker wire is just more expensive and takes up space?

will i get more Amps or more voltage for a high gauge wire?

 

[markus_i]

...

so basically thinker wire is just more expensive and takes up space?

will i get more Amps or more voltage for a high gauge wire?

It depends

If I assume that you are limited by the amount of space you have for the windings, thicker wire = less windings = lower voltage, higher current. The problem with this simplistic approach is that a generator consists not only of the wires and some magnets but also of the core the wire is wound on. If you don't wind the wires on a (magnetizable) core, i.e. use an air-core, you're wasting a lot of potential energy gain in a given volume (and with a given amount of copper) - air-cores are only sensible if you exceed the frequency ranges of metallic cores (i.e. >> 1 MHz), unlikely in any practical bicycle generator.
But if you use that core, determining the influence of the wire diameter as only parameter becomes problematic; the behaviour of the core will become a very dominant factor when calculating the energy output of your generator. While the above statement about wire thickness stays valid in a certain range around the 'correct' loading of the generator (i.e. you could, e.g., wind the generator for either 1A at 0.1 V/rpm with 1/2*n windings at 2*cross section, 0.5A at 0.2 V/rpm with n windings at 1*cross section or 0.25A at 0.4 V/rpm with 2*n windings at 1/2*cross section - numbers might be realistic), if you don't know the limits and behaviour of the core, you can only do the experiment and try and see what happens.

Theoretically, a bicycle generator can become quite complicated. If you're starting from scratch with unknown parts, just try it and see what happens.


Bye
Markus