Summary

Examples of experiments and
models on em induction
URDF - Uniud
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Summary
•Moving magnet acros a coil (experimental analysis and model)
•Magnet- spring system inducing alternate e.m.f
•The B field generated by a magnet and is flux
•.EM Induction phenomana in circuits: RL circuit analysis
•.EM Induction phenomana in circuits: coupilng circuits (the static
transformer)
•Models of a U coil with a moving bar
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Magnet moving across a coil
URDF - Uniud
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From Udine presentation of G. Bozzo: First analysis summary
sonar
To the
PC
Independet from
velocity
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From Udine presentation of G. Bozzo: First analisys summary
Equal and
opposite
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See Also
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s-1)
v(m
0,48
0,44
0,36
0,5
0,32
0,27
0,23
0,26
0,18
0,17
0,13
0,11
0,12
-0,19
-0,21
-0,27
-0,26
-0,32
-0,15
-0,14
-0,15
-0,52
-0,41
Vind (V)
-0,162
-0,148
-0,128
-0,171
-0,1
-0,096
-0,087
-0,09
-0,062
-0,057
-0,046
-0,038
-0,043
Correlation between: V and emfind
0,07
0,071
0,095
0,091
0,1
0,052
0,048
0,051
0,169
0,137
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e.m.f.ind  v
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Main results of the experiments:
R1) Integral in dt of the e.m.f. : proporzional to the flux variation
tf
Vind
dt =  ( B)
ti
Integral in dt of the e.m.f. : proporzional to the flux variation
Vind
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 v
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Analisys of the Bahaviour of the Vind vs position
Vind vs position
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Analisys of the Bahaviour of the
B (x) vs position
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Model –Experiment comparison
Data analysis:
fenomenological
behaviour:
B (x) = B/(x2+a2)3/2
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The model of the falling magnet
Equivalence: magnet and coil 
B = A / (z2 – b2)3/2
Hypotesis  B= A * Bmax (A phenomenological parameter)
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The model of the falling magnet in Excel
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The model of the falling magnet in Coach
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Magnet- spring system
inducing alternate e.m.f
URDF – University of Udine
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Force sensor
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To the
interfaced PC
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The collected data evidenced asimmetries related to the:
-Asimmetry of the magnet oscillation with respect to the coil position
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The collected data evidenced asimmetries related to the:
- suspected assimmetry of the magnet itself
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Phenomenon analysis n the Vind-position space
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Models of a U coil with a
moving bar
URDF – University of Udine
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The falling bar model in Coach: regime speed (Only the bar have a resitence)
The bar reach a
constant speed
The induced
current Jind tend to
constant value
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U coil with linear resistence (R of the coil increase when the bar fall down)
The speed of the bar
before decrease, after
increase
The induced current Jind
tend to zero
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The superconducting U coil
The bar oscillate
The amplitude of
J in the
superconductor
oscillate
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