HT instruments SIRIUS89N - Manual (Page 39)

SIRIUS89N
EN - 37
6.4. LOOP : MEASUREMENT OF LINE IMPEDANCE, FAULT LOOP
IMPEDANCE, PROSPECTIVE SHORT CIRCUIT CURRENT
CALCULATION AND PHASE SEQUENCE INDICATOR
Turn the
switch on LOOP
position.
The
F1 key permits to select one of the following measuring modes:
Mode " P-N" (the instrument measures the impedance between the phase
and neutral conductors and calculates the phase to neutral prospective
short circuit current).
Mode "
P-P" (the instrument measures the impedance between two
phase conductors and calculates the phase to phase prospective short
circuit current).
Mode "
P-PE" (the instrument measures the impedance between the
phase and protective conductors and calculates the phase to earth
prospective short circuit current).
Mode "
R
A
"
(the instrument measures the impedance between the
phase and protective conductors with a test current of 15mA in order to
avoid RCD tripping and calculates the phase to earth prospective short
circuit current).
Mode " " (the instrument detect the Phase Sequence in a three-phase
system).
CAUTION
Never disconnect the test leads when the message
"MEASURING" is
displayed.
6.4.1. High resolution Impedance measurement (0.1m Ω)
The instrument is connectable to an external
optional accessory (IMP57) useful for high
resolution impedance measurement close to a power transformer.
The high Resolution impedance measurement is available inside the
LOOP P-P, P-N, P-PE
modes by mean
Un/I∆n key. If You enable the High Resolution Impedance Measurement
mode without connecting IMP57 the following screen will be displayed (e.g: Loop P-N):
LOOP 29.01.04
Z=-----
Ω
R=-----
Ω X=-----Ω
IkSTD=----A
V1-2= 0V FRQ= 0.0Hz
NO IMP57
P-N Z2
Ω
FUNZ ZSTD ICAL RMT
For further details regarding IMP57 use and technical characteristics please refer to IMP57
user's manual or HT web site
www. htitalia.com.