16
MOM200A/600A
ZP-BB04E
BB0141NE
5 APPLICATION ExAMPLES
Expanded measuring range
The measuring range can be expanded by setting the
current lower than what was selected using the Test
current switch. Here, you must measure and calculate
the resistance manually, and the accuracy is somewhat
lower than normal. Application example (see below)
illustrates the procedure.
Application example
Important
Read the manual and comply with the
Safety instructions before using the mic-
roomhmmeter.
Always comply with local safety regula-
tions.
1]
Make certain that the mains are de-ener-
gized and that the test object is grounded.
2]
Keep the micro-ohmmeter disconnected from
the mains while making connections.
3]
Ground the micro-ohmmeter.
4]
Connect the two current cables and two
sensing cables (using the same polarities) to
the two sides measurement site. The sensing
cables must be connected close to the test
object.
5]
Connect the micro-ohmmeter to the mains.
6]
Turn the instrument’s ON/OFF switch ON.
7]
Select the desired current (400 A for exam-
ple) using the "Test current push buttons" on
the MOM600A.
8]
Clear, 0-set, the instrument by turning the
knob (16) on the variable transformer down
to "0", whereupon it will enter the current-
generation mode and LED (12) will light up.
9]
Increase the current as close as possible
(±1 A) to the desired value (100 A in this
case). Set the current accurately using the
digital measuring instrument.
10]
Press resistance button R. The instrument will
do the calculation and present an incorrect
resistance reading.
11]
To obtain the correct resistance reading you
must multiply the displayed reading by a
factor of X. To obtain X, divide the selected
current setting by the generated current.
Example
: 400/100 = 4.
Note
This procedure expands the micro-ohmmeter’s
measuring range, but the accuracy drops
somewhat.
12]
Turn off and disconnect the micro-ohmmeter
from the mains before doing any disconnec-
tion work or moving any cables or wiring.
