trifilar solinoids

[krienert]

Hello,
Early morning tea and some alone time led me to drawing a (poor) scetch for a solinoid coil setup for generating some voltage.
Though the image only depicts 3 turns, its really just a simplification of something like a couple hundred.
Watered down for lack of drawing skills sake.

So my question is, is there going to be some effeciancy increased with the two poles working together, persay from something like this?
http://www.instructables.com/id/Contactless-dynamo-powering-bike-safety-lights/

Pardon my stupidity if there is any, but im a curious cat.
cheers on this awesome gathering of minds (forum)

Joe

 

[krienert]

I am kinda seeing how this might have been more than a bit off the subject of bicycle transportation. Although it is a concept for dynamos, I might ask an admin to maybe pull this one.

Feeling a little stupid you might say.

uh, cheers!

 

[Steve K]

I've seen bifilar and trifilar windings used for switching power supply transformers. The advantage was lower skin resistance at high frequency due to smaller diameter wires and more surface area, as well as being easier to wrap around a core compared to an equivalent single solid magnet wire.

The limiting factor to the magnetic flux strength is the reluctance in the magnetic path, and this is usually dictated by the air gaps. The top of your drawing shows a very large air gap, which is going to produce a significant reduction in flux. It needs some high permeability material to bridge the top of those two cores (or a single U shaped core).

regards,
Steve K.