The factors in this system that would generate CEMF

In summary, the conversation discusses the factors that can cause counter-electromotive force (CEMF) in a solenoid, including the motion of a magnet, the inductance of the coil, and the attraction or repulsion between the magnet and electromagnet. The concept of inductance, which is the opposing EMF generated by changing current, is also explained. The conversation also raises the question of whether the initial higher voltage in a coil can be distinguished from CEMF.
  • #1
Wiz700
96
1
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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  • #2
The inductance of the coil perhaps.
 
  • #3
CWatters said:
The inductance of the coil perhaps.

Do explain!
 
  • #4
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.
 
  • #5
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?
 
  • #6
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"?
 

Related to The factors in this system that would generate CEMF

1. What is CEMF?

CEMF stands for Counter Electromotive Force and it refers to the voltage that opposes the flow of current in a circuit. It is also known as back EMF or back voltage.

2. What factors can generate CEMF in a system?

There are several factors that can generate CEMF, including the presence of a magnetic field, the movement of a conductor in a magnetic field, the use of inductors in a circuit, and the rotation of a motor.

3. How does CEMF affect a circuit?

CEMF can have several effects on a circuit, depending on its magnitude and direction. It can reduce the amount of current flowing in the circuit, cause voltage spikes, and even reverse the direction of current flow.

4. Can CEMF be controlled or mitigated?

CEMF can be controlled through the use of components such as capacitors or diodes in a circuit. It can also be mitigated by using proper shielding and grounding techniques.

5. How is CEMF related to Faraday's Law?

CEMF is closely related to Faraday's Law, which states that a changing magnetic field can induce a voltage in a conductor. This induced voltage is the CEMF in the circuit.

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