
30-6 Electrical Variables
whose equivalent circuit is denoted (L, LF, PMC) in Figure 30.2. e measured values of the equiva-
lent
cu
rrent-dependent
se
lf-inductance
an
d
th
e
eq
uivalent
re
sistance
ar
e
de
noted
L(i(t)) an
d
R
L
(i(t)),
re
spectively
. Ste
ady-state
L(i) va
lues
ca
n
be de
termined
fr
om
th
e
re
lation
L(i) ≈ ∆Φ(i)/∆i by me
asuring
th
e
ma
gnetizing
cu
rve
Φ(i). A sh
ape
of th
is
cu
rve
de
pends
no
t
on
ly
on th
e
am
plitude
of th
e
cu
rrent
i(t)
bu
t
al
so
on it
s
fr
equency
ω. e va
lue
of th
e
re
sistance
R
L
(i(t)) also depends on the current amplitude
an
d
fr
equency
. Wh
ere
a dc co
mponent
of th
e
cu
rrent
in th
e
in
ductive
el
ement
(b
ias
cu
rrent)
is ap
plied,
th
e
in
duct ...