Motoring Effect in DC Motors: Magnetic Field Interaction or Lorentz Force?

[jim hardy]

Seems that it's not as straightforward as it looks in the diagram.. Thank you very mucha for your patient replies.. I hope I didn't bore you with this long thread..

not at all, i wondered what you were driving at.

There's always several ways to teach a subject.
My vector calculus is rusty .
Somebody who's fluent in it might prefer that approach.
old jim

 

[cnh1995]

not at all, i wondered what you were driving at.

There's always several ways to teach a subject.
My vector calculus is rusty .
Somebody who's fluent in it might prefer that approach.
old jim

Just one last question..If I placed another wire very close to the original wire in the diagram and sent current through it in the opposite direction, the resultant magnetic field due to both the currents will be almost 0. Will there be a force on the wire?? There won't be any distortion of flux as seen in the original diagram. Will Lorentz force act on them??

 

[jim hardy]

Not trying to duck your question here...

I assume your two wires are physically kept close together by something like glue , or their innate rigidity ? If not the geometry will change and the problem becomes dynamic.

I'll answer that each wire will experience a vertical force from its Lorentz force effect and those forces of course sum to zero. (ignore the torque couple for now)

and there's an additional force on each wire from the other one
http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/wirfor.html
of course you postulated current in opposite directions not same direction as in this figure - so wouldn't that force be repel not attract ?

I've been thinking nights about your questions

and they make me ponder what is nature of space that force is transmitted between objects over a distance by magnetic and electric and gravity fields?
Higher math is able to describe the interactions out there in free space not just at the objects.

But we can only sense the resulting force at an object like a wire or a charged piece of matter where we can attach a force measuring device..
I need an aether.

I think that's why i stick with my 19th century analogies - my algebra is so prone to mistakes that i have to visualize the forces before i'll believe the math.
That is a handicap. I really advise you to master Vector Calculus and Maxwell's equations, they've become the coin of the realm.

old jim

 

[jim hardy]

ps thanks for your patience with me .

 

[cnh1995]

ps thanks for your patience with me .

Thanks a lot..:-)I think its time for me to start working on higher math..

 

[jim hardy]

I think its time for me to start working on higher math..

There are plenty of extraordinarily capable people here at PF ...

I'll not pretend I'm qualified to teach vector calculus.

Still learning something every day --

old jim