METREL MI 3100 S EurotestEASI, Instruction Manual

Page: 47 / 91

MI 3100 s, MI 3100 SE Eurotest EASI Measurements
47
5.6.1 Line impedance and prospective short circuit current
Circuits for measurement of line impedance
Figure 5.28: Phase-neutral or phase-phase line impedance measurement
– connection of plug
commander and 3-wire test lead
Line impedance measurement procedure

Select the Zline function using the function selector switch.

Set sub-function to Zline using UP / DOWN keys.

Select test parameters (optional).

Connect test cable to the instrument.

Connect test leads to the item to be tested (see Figure 5.28 ).

Press the TEST key to perform the measurement.

Store the result by pressing the MEM key (MI 3100 SE only).
Figure 5.29: Examples of line impedance measurement result
Displayed results:
Z ............... line impedance
Isc ............ prospective short-circuit current
Lim ........... low limit prospective short-circuit current value
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
4.3.5 Isc factor ).
U
n
Input 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)