METREL EasiPLUS MI 3000 - Page 60

MI 3000 EasiPLUS IT supply systems
60
B.3 Measurement guides
The user has to select the IT supply system in the instrument before testing it. The
procedure for selecting the IT supply system is defined in chapter 4.4.1 Supply system
setup
. Once the IT system is selected the instrument can be used immediately. The
instrument keeps selected IT system when it is turned off.
The table below contains functions of the instrument including compatibility notes
related to IT system.
IT system functions Notes
Contunuity functions
RLOW
Continuity
Independent of selected supply system.
Insulation
Independent of selected supply system.
Line impedance
Line impedance Impedance Z
L1-L2
.
Prospective short circuit
current
I
PSC
for rated U
L1-L2
.
Fault loop impedance
Independent of selected supply system.
Fault loop impedance
Prospective fault current
Voltage, frequency
Symbols modified for IT system.
Phase rotation
Three-phase system automatic detected.
RCD functions
Independent of selected supply system.
Contact voltage U
C
Trip-out time
Trip-out current
Automatic test
Bypassing principle shown in figure B.3.
PE test probe
Active, but does not inhibit selected test if voltage is
detected.
B.3.1 Voltage
Figure B.2: Example of voltage and frequency measurements
Displayed results for single phase system:
L1-L2 ......Voltage between line conductors,
L1-pe ......Voltage between line 1 and protective conductor,
L2-pe ......Voltage between line 2 and protective conductor.