sections and connection points should be designed to avoid
excessive heating.
n
The current measuring ranges up to 660 mA are protected to a
short circuit current of 25 A by a fuse 1.6 A/1000V AC/DC in
conjunction, with power diodes. The cut-out capacity of the fuse is
10kA at a rated voltage of1000V AC/DC and ohmic load.
n
The 10 A current measuring ranges are protected by a 16A/ 1000V
AC/DC fuse. The cut-out capacity of the fuse is 30 kA at a normal
voltage of 1000V AC/DC and ohmic load.
n
Replacement of the fuses is described in section “17. Maintenance’’.
Caution
The measuring ranges 16 A of Multimeter
NP10-3
are not protected by a fuse!
10.1 AC current measurement with (clip-on) current transformer
10.1.1 Transformer output mA/A
Caution
If current transformers are operated with an open circuit on the
secondary side, e.g. due to defective or disconnected leads, a blown
fuse in the meter, or a wrong connection, dangerously high voltages can
occur at the connectors. Therefore, verify that the current circuit of the
multimeter and secondary winding of transformer connected to the
multimeter form an intact circuit. Connect the transformer to the sockets
and mA or A The maximum permissible operating voltage is the
nominal voltage of the current transformer. When reading the measured
value, take into account the transformer ratio and the additional error in
indication.
Transformer output Multimeter
NP10-2
The multimeter
NP10-2
shows the switching position and the
corresponding sockets. Connect to this socket a (clip-on) current
transformer with a transmission ratio of 1000:1 then the measured
values are displayed directly in the “A’’ range.
10.1.2 Transformer output V
Many transformers have voltage output (refered as mV/A) The
secondary output must therefore be connected to the connection
sockets “ ” and “ V ”.
11
