What Happens to the Magnetic Field Outside of a Motor Coil?

Click For Summary
SUMMARY

The discussion centers on the behavior of magnetic fields outside of a motor coil, particularly in DC motors. It is established that the magnetic field generated by the coil interacts with the cylindrical field magnets, creating a couple that facilitates rotation. The magnetic lines of flux primarily travel through the steel casing of the motor, resulting in minimal flux straying beyond the motor's structure. The field strength outside the coil is significantly weaker than at the center, where the maximum field strength is observed.

PREREQUISITES
  • Understanding of DC motor operation and magnetic fields
  • Familiarity with magnetic field lines and their behavior
  • Knowledge of the interaction between coils and permanent magnets
  • Basic principles of electromagnetism
NEXT STEPS
  • Research the principles of magnetic field strength in coils and their external effects
  • Learn about the construction and function of cylindrical field magnets in DC motors
  • Explore methods to measure magnetic field strength outside of motor coils
  • Investigate potential applications for harnessing stray magnetic fields
USEFUL FOR

Physics enthusiasts, electrical engineers, and anyone interested in the principles of electromagnetism and motor design.

crash_ndie
Messages
8
Reaction score
0
hello sorry for the bad description I've always loved physics since i was in school so I've decided to start a project so please forgive my lack of technical wording and ignorance i promise am a quick learner lol

on a motor we use electricity / current passed though a coil to create a magnetic field focused down the center of the motor to make it spin.

My question is what happens to the field out side of the coil.

(wish could post a pic be so much easier to ask my question)

if the field in the center of the motor is , say 10 as its maximum what will it be on the out side of the coil ?
 
Physics news on Phys.org
crash_ndie said:
on a motor we use electricity / current passed though a coil to create a magnetic field focused down the center of the motor to make it spin.
Hi crash_ndie. Welcome to Physics Forums.

I wouldn't exactly agree that the field is directed to the centre of the motor; the stator field is directed to where it will best interact with the rotor field.
My question is what happens to the field out side of the coil.
I think you'll find in a typical motor that each pole is firmly bolted to the steel case of the motor, and poles alternate around the casing, N, S, N, S, and so on. So the magnetic lines of flux travel via the steel casing around to the adjacent poles to reenter the motor through the pole face of the adjacent poles. That way, very little flux strays beyond the motor.
 
crash_ndie said:
on a motor we use electricity / current passed though a coil to create a magnetic field focused down the center of the motor to make it spin.

My question is what happens to the field out side of the coil.

(wish could post a pic be so much easier to ask my question)

if the field in the center of the motor is , say 10 as its maximum what will it be on the out side of the coil ?

In a DC motor , when current flows in the coil, the magnetic field of coil interacts with the magnetic field of cylindrical field magnets , due to the combined effect , the coil is acted upon by a couple. The field is linked with the coil and another one is linked with cylindrical field magnets. At the centre of coil the effect of magnetic field is zero. They appear to be in same direction. Hence there are these two system of magnetic fields.

They are maintained constant. When coil plane comes at right angles to the plane of magnetic field of cylindrical magnets , the effect is zero but due to angular momentum it continue to rotate. After 180 degrees the split rings reverse and it continue its process like this, clockwise or anticlockwise.
 
say we base the motor on this type were the coil is out side and the rotor is in the center
see attatched pic..

on the second pic (best i could find to show the field) picture the magnet as the spining motor C & D.

on the field A, E & B what's happening to the field in relation to north and south, dose it flux n,s,n,s,n,s up the length of the coil to the center of the motor, Or is it a constant n,s to the center of the coil.

basically What am trying to find out, is the field as strong on the out side of a coil as it is in the center of the coil. Could this spare magnetic field be re - used
 

Attachments

  • Magnetic-Alternator.jpg
    Magnetic-Alternator.jpg
    16.3 KB · Views: 547
  • i_magnetic_field.jpg
    i_magnetic_field.jpg
    13.3 KB · Views: 491

Similar threads

  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 3 ·
Replies
3
Views
1K
  • · Replies 31 ·
2
Replies
31
Views
5K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 1 ·
Replies
1
Views
3K
  • · Replies 12 ·
Replies
12
Views
3K
  • · Replies 21 ·
Replies
21
Views
4K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 42 ·
2
Replies
42
Views
3K
  • · Replies 8 ·
Replies
8
Views
4K