Measurement Procedure And Results Of "P-P" Mode - MARTINDALE VR2250 User Instruction Manual

6.4.3. Measurement procedure and results of "P-P" mode

1. Select P-P mode by means of the F1 key.
2. Connect the Red, Green and Black connectors of the three-terminal mains cable or
of the split cables to the corresponding input terminals of the instrument B1, B3, B4
Instrument connection for P-P test in a 400V three-phase system
3. Connect the mains plug into a 230V 50Hz socket or the crocodiles to the
conductors of the three-phase system (see previous pictures).
4. If possible disconnect all low impedance loads downstream the point at which
the measurement is to be taken; as such impedance would be in parallel with
the line impedance to be measured.
START
5. Press the START key. The instrument starts the test.
STOP
The P-P measurements in a 400V system make a test current of 11.5A approx.
This may cause the tripping of magnetic protection switch with nominal value
lower than 10A. If necessary perform the test upstream of the switch. Never
disconnect the test leads when the message "MEASURING" is displayed.
At the end of the test
the instrument emits a
double sound signal
indicating that the test
is correctly
terminated and
displays the values
alongside.
Working mode
Formula for calculation of prospective short circuit current:
Where U = phase to phase voltage
N
This result can be stored pressing the SAVE key twice (according to paragraph 9.1).
1
3
N
Black
CAUTION
LOOP
0.57
701A
FRQ=50.0HZ
VP-P=402V VP-PE=231V
P-P
FUNC Z2Ω
U
=
N
I
CC
Z
PP
Page 40 of 131
I1
Red
B1 B2 B3
Green
05.06.01
Value of phase to phase
impedance expressed in Ω.
Ω
Value of the phase to phase
prospective short circuit
current expressed in Amps
calculated according to the
following formula.
≤ 150
127 if V
meas
230 if 150V< V
400 if V > 260
meas
VR2250
B4
≤ 260
meas