MI 3321 MultiservicerXA
Machine testing operating mode
128
Examples of fault loop impedance measurement results
Displayed results:
Main result ............. Fault loop impedance,
I
SC
.......................... Prospective fault current,
Ul-pe ...................... Voltage UL-PE
Un-pe ..................... Voltage UN-PE
U
n
Input voltage (L-PE)
110 V
(93 V
U
L-PE
134 V)
230 V
(185 V
U
L-PE
266 V)
Notes:
The Z LOOP test may trip out the RCD in RCD-protected electrical installation.
The fault loop impedance is measured between L and PE connection points of
machine’s loads. Result is compared with
Ia
of belonging disconnection devices
(fuses, breakers).
9.2.5.1
Z m
L-Pe, High precision loop impedance measurement
The measurement is performed with Impedance adapter A1143. It is recognized in Z-
LOOP function. With this adapter, low impedances from several m
up to 19.99
can
be measured. The measurement is covered by requirements of the EN 61557-3
standard.
Impedance adapter connected
Test parameters for Z m
L-Pe loop impedance measurement
Function Z m
L-Pe (Z-LOOP)
FUSE type
Selection of
fuse
type
[*F, NV, gG, B, C, K, D] *
FUSE I
Rated current
of selected fuse
FUSE T
Maximum
breaking time
of selected fuse
Isc_lim
Minimum short circuit
current
for selected fuse combination.
See
Appendix C
for reference fuse data.
