Transfer impedance (Z
T
) can be assessed on the basis of
the following factors:
-
The conductibility of the shield material.
-
The contact resistance between the individual
shield conductors.
-
The shield coverage, i.e., the physical area of the
cable covered by the shield - often stated as a
percentage value.
-
Shield type, i.e., braided or twisted pattern.
a.
Aluminum-clad with copper wire.
b.
Twisted copper wire or armored steel wire cable.
c.
Single-layer braided copper wire with varying
percentage shield coverage.
This is the typical Danfoss reference cable.
d.
Double-layer braided copper wire.
e.
Twin layer of braided copper wire with a
magnetic, shielded/armored intermediate layer.
f.
Cable that runs in copper tube or steel tube.
g.
Lead cable with 0.043 in [1.1 mm] wall thickness.
Figure 5.38
How to Install
VLT
®
HVAC Drive Design Guide
5-36
MG11BB22 - VLT
®
is a registered Danfoss trademark
5
5
