Some thoughts on a homopolar idea.

[gravityblock]

I believe that this idea is very unique as it exploits a special force.

Are you referring to the drawing you first posted in this thread, or the drawing I modified from DreamThinkBuild (DTB)?

There may be a way to brute force the counter torque with a gear.  It's called a worm gear.  In a worm-and-gear set, the worm can always drive the gear. However, if the gear attempts to drive the worm, it may or may not succeed.  I know the gear will introduce friction into the system, but I'm sure the friction would be much less than taking the full force of the counter torque.  Just a thought.

GB

[jadaro2600]

These are my word of encouragement: Keep up the good work.

[gravityblock]

@broli:

Two simple questions for you.  In your illustration, if the magnet wasn't glued to the disc and the magnet could freely rotate on a separate axle, would the magnet rotate when current is flowing in the small disc?  Would the small disc rotate?

If you can't answer this question, then maybe someone else can.  My previous question to you in my other post is still unanswered.  I am sincere at getting to the bottom of this counter torque issue, but we need to have a discussion if I am to learn anything.

A simple yes or no to those questions will be good.  This will help me to understand the forces at play.

Thanks,

GB

[broli]

Are you referring to the drawing you first posted in this thread,

Yes.

@broli:

Two simple questions for you.  In your illustration, if the magnet wasn't glued to the disc and the magnet could freely rotate on a separate axle, would the magnet rotate when current is flowing in the small disc?  Would the small disc rotate?

Here are some cases.

Case 1: magnet and disc glued
Result: magnet+disc rotates and a force acting on outside circuit.

Case 2: both magnet and disc are attached to independent axles
Result: magnet will remain stationary while disc rotates
Reason: Disc and magnet exert force on each other, this causes disc to rotate...but outside circuit also exerts force on magnet, thus canceling out first force cause by disc, resulting in magnet remaining stationary.

Case 3: magnetless setup
Result: http://www.electricstuff.co.uk/bbmotor.html (minus the heat theory crap)
Reason: When disc is given initial spin weak but present magnetic field is made, this causes a force on outside circuit and results in torque on disc. Stefan shows that 100's of amperes are needed, in my views this is logical since the magnetic field caused by initial rotation is tiny. Of course this can have some interesting anomalies since what is causing the back emf now, if there even is such a thing.


You won't find these cases or reasons on wikipedia.

Edit: added another case.

[gravityblock]

@broli:

Thank you for the answers.  The "results" are what I expected and just wanted verification so I am on the right path.  I'm starting with the basics and will be moving to more complicated issues.

You said the magnet would rotate in Case 2 due to the force being exerted on it by the disc, but the force from the external circuit would be in the opposite direction on the magnet, thus canceling the forces with no net rotation of the magnet. 

That makes total sense, but here's the catch.  If the magnetic field of the magnet remains stationary while the magnet is rotating, then why would the magnet rotate if the magnetic field had a force exerted on it?   Either way, if the magnetic field rotates or remains stationary due to the forces being exerted on it from the disc and/or external circuit, the magnet wouldn't rotate.

So, my next question is, Does the force from the disc and external circuit act on the electric field of the magnet or the magnetic field of the magnet?  If the forces act's on the electric field of the magnet, then the magnet's rotation is canceled.  If the forces act's on the magnetic field of the magnet, then the rotation of the magnetic field is either canceled or it remains stationary with either force.  The importance of this should become clear when we discuss the counter torque, BEMF, and other issues.

I appreciate you taking the time to answer these questions.


GB