Benning IT 130 - Page 51

BENNING IT 130 Measurements
- 51 -
Results displayed:
∆U............ voltage drop
Isc ............ prospective short-circuit current
Z............... line impedance at the measuring point
Zref .......... line impedance at the reference point
The voltage drop is calculated as follows:
[ ]
100
)(
% ⋅
⋅
−
=∆
N
NREF
U
IZZ
U
with:
∆U ........ calculated voltage drop
Z........... line impedance at the measuring point
Z
REF
...... line impedance at the reference point
I
N
.......... nominal current of the fuse
U
N
......... nominal voltage (see table below)
U
n
Voltage range (L-N or L1-L2)
110 V
(93 V ≤ U
L-N
< 134 V)
230 V
(185 V ≤ U
L-N
≤ 266 V)
400 V
(321 V < U
L-L
≤ 485 V)
Notes:
 If the reference impedance is not set, Z
REF
is assumed to be 0.00 Ω.
 The Z
REF
value is deleted (set to 0.00 Ω) by pressing the "CAL" key, if the installation
tester is not connected to a voltage source.
 The I
SC
value is calculated as described in chapter 5.6.1 "Line impedance and
prospective short-circuit current".
 If the voltage measured is outside the ranges listed in the table above, the ∆U value will
not be calculated.
 High fluctuations of the nominal voltage might influence the measuring results ( icon
on the LC display). In this case, it is recommended to repeat the measurements and to
check whether the measuring results are stable.