The factors in this system that would generate CEMF

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Discussion Overview

The discussion centers on the factors that generate Counter Electromotive Force (CEMF) in a solenoid system with a stationary magnet. Participants explore the roles of inductance, motion, and the relationship between current and magnetic fields in this context.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant questions whether the motion of the magnet is the only factor causing CEMF when the solenoid is powered on or off.
  • Another participant suggests that the inductance of the coil may play a role in generating CEMF.
  • A different viewpoint emphasizes that the motion of the magnet results from the attraction or repulsion between the magnet and the solenoid, indicating that CEMF is a consequence of this motion.
  • One participant seeks clarification on whether the initial higher voltage in the coil, when the current changes, can be distinguished from CEMF.
  • A later reply reflects on the definition of inductance as the opposing EMF generated by changing current and its relation to magnetic flux.

Areas of Agreement / Disagreement

Participants express differing views on the factors contributing to CEMF, with no consensus reached on the primary causes or the relationship between inductance and CEMF.

Contextual Notes

Participants reference the concepts of inductance and magnetic flux without resolving the implications of these definitions or their interdependencies.

Wiz700
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Hi

I have a Solenoid(No core) and a small magnet that is stationary in it.
The Solenoid is powered off/on. What would cause Counter-EMF if the Solenoid is on/off?
Only the motion of the magnet?

What are other factors would generated EMF in my coil?
Other than the magnet's motion + the power input of course :P
 
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The inductance of the coil perhaps.
 
CWatters said:
The inductance of the coil perhaps.

Do explain!
 
Another thing, the motion of the magnet is a result of the attraction or repulsion of the two.
Only AFTER the force is applied the motion starts. So CEMF is a result of the reaction, well on of the results motion is too a result :)

In fact! Motion is a result of the magnet + electromagnet's attraction/repulsion and CEMF is a result of that motion.
 
Wiz700 said:
Do explain!

When turned on the current through the coil inductance can't change instantly. The coil voltage will initially be higher. As the current builds the voltage will fall to it's final value. During that (brief?) time the voltage is higher than normal. Can that be distinguished from CEMF?
 
Well I just learned "Inductance" as: The opposing EMF that is generated by changing current, thus caused a change in the magnetic field = change in the magnetic flux thus INDUCED EMF opposes the applied EMF.

I assume this is what you meant? "L"?
 

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