Comparison of linear and rotating systems
Linear System
Rotating System
Part A = cylindrical bar magnet. Part B = conductor. Part C = Voltmeter and leads
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Linear system |
Rotating system |
||||||
|
A |
B |
C |
V |
A |
B |
C |
V |
|
· |
· |
· |
No |
· |
· |
· |
No |
|
· |
· |
¬ |
No |
· |
· |
¬ |
No |
|
· |
¬ |
· |
Yes |
· |
¬ |
· |
Yes |
|
· |
¬ |
¬ |
Yes |
· |
¬ |
¬ |
No * |
|
¬ |
· |
· |
Yes |
¬ |
· |
· |
No |
|
¬ |
· |
¬ |
Yes |
¬ |
· |
¬ |
No |
|
¬ |
¬ |
· |
No |
¬ |
¬ |
· |
Yes |
|
¬ |
¬ |
¬ |
No |
¬ |
¬ |
¬ |
No * |
Note
·
= not moving (relative to observer). ¬ = moving relative to observerNo
*= Normally No, but this is the subject of the idea in this web site.Linear system
It can be seen on inspection that a relative movement between A and B produces an emf which is observed by the voltmeter
Rotating system
This is very interesting, since there are many differences to a linear system. It seems that a ROTATING conductor in a magnetic field produces an emf. If the rotating leads and voltmeter produce the SAME emf, then no emf is read by the voltmeter (because the emf would be in opposition to the emf generated by the conductor). But if the rotating leads and voltmeter could rotate without creating an emf, then an emf would be observed by the voltmeter.
See this idea