Understanding Motor and Inductor Emf

  • Thread starter Thread starter momomo_mo
  • Start date Start date
  • Tags Tags
    Inductor Motor
AI Thread Summary
Emf is induced in motors through the interaction of current and a magnetic field, causing coil rotation and a change in magnetic flux. In inductors, a sudden change in magnetic flux occurs when a switch opens, inducing emf. The discussion raises a question about why no emf is induced when a coil is suddenly stopped, despite a change in magnetic flux. It is explained that if the inductor is not moving, the magnetic field remains constant, resulting in no induced emf. Clear communication is emphasized for effective responses in technical discussions.
momomo_mo
Messages
25
Reaction score
0
In these two cases , emf will be induced in different way.
for motor: current +B-field-->Force-->Coil rotate-->change of magnetic flux-->emf inducedd in the coil
for inductor , when the switch suddenly openfrom closes switch, there are a sudden change of magnetic flux ,there emf will be induced

the thing I want to ask:
why when the coil is suddenly jammed and come to stop,there will not be any induced emf in this cases??
isn't it just the case of inductor,there are a change of magnetic flux
from many to none magnetic flux ?

why?

thank you
 
Physics news on Phys.org
HeLPplease
 
Usually people that answer to posted questions, try to write theirs answers clearly and in a correct language without stupid abbreviations, like "u" four "you". I think they deserve that you write your questions clearly, without shortcuts and in a text you could show to your English teacher.
Most people who answer your questions are not your pals. Some of them happen to be older than your actual teachers.
If your post had not been answered, it is not that no one is able to answer. It is just that no one is willing to decode your so badly written question.
 
In the two examples given:
for motor: alternating current +B-field-->Force-->Coil rotate-->change of magnetic flux-->emf inducedd in the coil

for inductor , when the switch suddenly openfrom closes switch, there are a sudden change of magnetic flux ,there emf will be induced
The motor has an applied alternating current, and the time varying current induces a time varying magnetic field (which would otherwise by constant).

In the inductor, the closing of the switch allows a time varying current. A constant current would induced a constant B-field.

If an inductor is moving in a constant magnetic field and emf will be induced. If the inductor is not moving, i.e. stopped, then the field is constant (non-varying) and no emf is induced.

See principle of induction motor - http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/indmot.html

Inductance concepts
http://hyperphysics.phy-astr.gsu.edu/hbase/electric/induct.html
 
SORRY
I think it will be easier for the readers to read my question by using flow chart.I apologized for my poor english because I usually weak in expressing my point of view in English.I used to write in Chinese.Really sorry.Sorry for all the readers.Sorry for my distrubance.
 
You are welcome to post questions. Just try to write them clearly.
 
Hi there, im studying nanoscience at the university in Basel. Today I looked at the topic of intertial and non-inertial reference frames and the existence of fictitious forces. I understand that you call forces real in physics if they appear in interplay. Meaning that a force is real when there is the "actio" partner to the "reactio" partner. If this condition is not satisfied the force is not real. I also understand that if you specifically look at non-inertial reference frames you can...
This has been discussed many times on PF, and will likely come up again, so the video might come handy. Previous threads: https://www.physicsforums.com/threads/is-a-treadmill-incline-just-a-marketing-gimmick.937725/ https://www.physicsforums.com/threads/work-done-running-on-an-inclined-treadmill.927825/ https://www.physicsforums.com/threads/how-do-we-calculate-the-energy-we-used-to-do-something.1052162/
I have recently been really interested in the derivation of Hamiltons Principle. On my research I found that with the term ##m \cdot \frac{d}{dt} (\frac{dr}{dt} \cdot \delta r) = 0## (1) one may derivate ##\delta \int (T - V) dt = 0## (2). The derivation itself I understood quiet good, but what I don't understand is where the equation (1) came from, because in my research it was just given and not derived from anywhere. Does anybody know where (1) comes from or why from it the...
Back
Top