Loop; Calculation And Phase Sequence Indicator; High Resolution Impedance Measurement (0.1Mω); Loop : Measurement Of Line Impedance, Fault Loop Impedance, Prospective Short Circuit Current Calculation And Phase Sequence Indicator - MARTINDALE VR2250 User Instruction Manual

6.4.

LOOP

: MEASUREMENT OF LINE IMPEDANCE, FAULT LOOP
IMPEDANCE, PROSPECTIVE SHORT CIRCUIT CURRENT

CALCULATION AND PHASE SEQUENCE INDICATOR

Turn the switch on LOOP
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
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 "
system).
Never disconnect the test leads when the message "MEASURING" is
displayed.
6.4.1. High resolution Impedance measurement (0.1mΩ)
The MARVR2250 model 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):
For further details regarding IMP57 use and technical characteristics please refer to IMP57
user's manual or Martindale Electric web site www.Martindale-Electric.co.uk.
position.
Ω" (the instrument measures the impedance between the
A
" (the instrument detects the Phase Sequence in a three-phase
CAUTION
LOOP
Z=-----Ω
R=-----Ω X=-----Ω
IkSTD=----A
V1-2= 0V FRQ=
NO IMP57
P-N Z2Ω
FUNZ ZSTD ICAL
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0.0Hz
RMT
VR2250