Sonel MPI-540 User Manual

MPI-540 – USER MANUAL
43
R – resistance of the tested circuit
X
L
– reactance of the tested circuit
U
L-PE
– voltage relative to the pro-
tective conductor
f – frequency
Selecting the bar hides the
menu.
Save the measurement to the meter memory using the icon. A detailed description of
memory management is contained in section 5.1.3.
The last measurement can be recalled using the icon.
 Maximum measurement time is about 4 seconds. The measurement can be inter-
rupted by pressing the button.
 In the electrical installations with 30 mA RCD's, the sum of leakage currents of the
installation and the test current may trigger the RCD. If this happens, try to reduce
the leakage current in the tested mains (for example by disconnecting loads).
 The function works for residual current devices of rated current ≥ 30 mA.
 When many measurements are performed in short time intervals, the meter may
emit a large amount of heat. As a result of this, the housing of the device may be-
come hot. This is normal. In addition, the meter is equipped with the protection
against excessive temperature.
 After approx. 15 consecutive measurements of the fault loop wait until the instru-
ment cools down. This limitation is due to the high current measurement and multi-
functionality of the meter.
 Minimum interval between successive measurements is 5 seconds. The displayed
message indicates that it is possible to perform another measurement.
Until the message is displayed, the meter prevents any measurements.
3.4.5 Prospective short-circuit current
The meter always measures fault loop impedance Z
S
and the displayed short-circuit current is
calculated according to the following formula:
S
k
Z
U
I 
where:
Z
S
– measured impedance,
U – voltage dependent on the network rated voltage settings U
n
(section 3.4.1 point ):
I
k
(U
n
)
U = U
n
I
k
(U
0
)
U = U
0
for U
0
< U
n
U = U
n
for U
0
≥ U
n
where:
U
n
– nominal voltage of the network,
U
0
– voltage measured by the meter.

Sonel MPI-540 Specifications

General

Brand	Sonel
Model	MPI-540
Category	Measuring Instruments
Language	English