# I need your help in understanding induced EMF, B fields, C-EMF

Discussion in 'General Electronics Discussion' started by Dretron, Mar 12, 2013.

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1. ### Dretron

101
0
Jun 9, 2012
Hello everyone .

I've been studying electromagnetism specifically faraday's law + Ampere's and Lenz in a circuit and in a motor.
I need your help to make sure my logic is right!

So here I go!

- When EMF(V) is created from a certain source(Battery, generator, solar cell) it causes a flow of current to be moved from one terminal to another.
That flow of charge(current(I)), creates a magnet field surround the wire.( Right so far?)
Now, when Voltage is 10V, and the current is 0. There is no magnetic field because there is no flow of charge power = 0, so the B field can't be produced.
- As the current drops to 0. There is no demand anymore in the circuit so the voltage drops very quickly(Steve we can call this Semi-Instant).
- When a magnet passes(Not through) a coil, it creates EMF. If that coil had EMF flowing thought it, it would be C-EMF created by the magnet.

-When a magnet creates EMF, that moves current, and that current creates a magnet field that opposes the magnet.
- Another point, when a magnetic field is generated from "current" regardless if another magnetic field is present and x10 x100 x1000 times stronger, that B field created by the current is attracted to it.

What else I'm I missing... um...
I don't know let me see you all reviewing my summary and go from there!

Useful illustrations:

Last edited: Mar 12, 2013
2. ### dietermoreno

238
0
Dec 30, 2012
Hyper physics. You already have the link that has the answers to your questions. Hyper physics helped me a lot in Physics II.

3. ### Dretron

101
0
Jun 9, 2012
Its good to share the concepts with the experts to see what they have to criticize and teach me.

Some idea's is not answered in Hyper physics.

4. ### Dretron

101
0
Jun 9, 2012
Now, when Voltage is 10V, and the current is 0. There is no magnetic field because there is no flow of charge power = 0, so the B field can't be produced.

- Another point, when a magnetic field is generated from "current" regardless if another magnetic field is present and x10 x100 x1000 times stronger, that B field created by the current is attracted to it.

These idea's are not answered directly.
I had to figure that out on my own.

Last edited: Mar 12, 2013
5. ### Dretron

101
0
Jun 9, 2012

When the circuit is open
current can not flow. Voltage and current = 0.
But what if current was zero and Voltage was a certain integar.
The B field = 0 too.

6. ### Dretron

101
0
Jun 9, 2012
"Another point, when a magnetic field is generated from "current" regardless if another magnetic field is present and x10 x100 x1000 times stronger, that B field created by the current is attracted to it."

Amateur's magnetic field < Magnetic field surrounding it.
Can the armatures move around that magnetic field? With a certain power input? Regardless of that input, the B field is weak.

7. ### BobK

7,682
1,688
Jan 5, 2010
You put current on the armature windings, and they produce a N and a S pole. These are attracted to the S and N poles of the fixed magnets, and the armature moves in that direction. The motion of the coils in the magnetic field causes a voltage to be created in the coils that opposes the voltage applied.

Bob

8. ### Dretron

101
0
Jun 9, 2012
Agreed.
Regardless of the other factor's in the system the armature will have the magnetic force acted on it.

Another example is:
Two large permanent magnets and there is an armature that is x100 times smaller and weaker than both of them, it will still be able to move due to the magnetic force applied to it.

Thanks Bob.

9. ### Dretron

101
0
Jun 9, 2012
I aslo realized that when a circuit's current approches zero there the magnetic field is decreasing and that itself creates a magnetic field.