Environmental Engineering Reference
In-Depth Information
Table 4.22 Bus bar inductance comparison
Bus bar structure
Conductor self-inductance (nH)
Parallel, laminar
14
l
W
2
:
6
f
L
¼
d
þ
p
L
t
t
W
Bar
Bar
d
Dielectric
þ
Circuit trace
d
W
þ
t
3
2
L
¼
5
l
ln
L
d
W
W
t
Bar
Bar
Dielectric
þ
Single plate
2
l
W
þ
t
2
ð
W
þ
t
Þ
9
l
1
2
L
¼
5
l
ln
þ
L
W
t
Bar
Dielectric
Skin depth of high frequency currents into the bar are determined by calcu-
lating the ac resistance of the bar:
s
1
p
f
ms
dð
f
Þ¼
ð
m
; WÞ
ð
4
:
38
Þ
r
L
W
dð
f
Þ
R
ac
ð
f
Þ¼
where skin depth is in metres and ac resistance is in ohms. The parameters are the
usual ones for skin depth, permittivity and conductivity of the bar material. For ac
resistance the bar resistivity is used as well as geometry, length
L
and width
W
of
