TESTBOY TV 450
Earth resistance
46
Line to neutral
Line to line
Figure 5.28: Examples of line impedance measurement result
Displayed results:
Z..............Line impedance,
I
SC
............Prospective short-circuit current,
Lim ..........Low limit prospective short-circuit current value or high limit line
impedance value for the UK version
.
Prospective short circuit current is calculated as follows:
Z
k
Un
I
SC
SC
×
=
where:
Un ........Nominal L-N or L1-L2 voltage (see table below),
ksc .......Correction factor for Isc (see chapter
4.2.6
).
U
n
Input voltage range (L-N or L1-L2)
115 V
(100 V
≤
U
L-N
<
160 V)
230 V
(160 V
≤
U
L-N
≤
264 V)
400 V
(264 V
<
U
L-N
≤
440 V)
Note:
High fluctuations of mains voltage can influence the measurement results (the
noise sign
is displayed in the message field). In this case it is recommended
to repeat few measurements to check if the readings are stable.
