Evaluating The Measurement Values; Measuring Line Impedance - Gossen MetraWatt ProFiTEST C-GB int. Operating Instructions Manual

7.3

Evaluating the Measurement Values

Maximum allowable loop impedance Z
help of the on page 34. These are the maximum values which may be dis-
played after taking the device's
maximum measuring error into consideration (under normal measuring
conditions). Intermediate values can be interpolated.
The maximum allowable current rating for the protective device (fuse or
breaker) can be determined for a nominal line voltage of 230 V with the
help of the Table of Minimum Display Values for Short-Circuit Current on
page 35 based upon measured short-circuit current, under consideration
of the device's maximum measuring error (in compliance with
DIN VDE 0100, part 610).
After measurement has been performed, allowable fuse types can be dis-
played by pressing the
current ratings depending upon fuse type and breaking conditions.
Note
is greater than 100 , the following error message
If Z
Loop
appears: "defective F1 ...". No test current can be made available
when the following error occurs: resistance too great, fuse
defective or earth electrode is not connected.
7.4

Measuring Line Impedance

Line impedance can only be measured with the Z521A 3-phase measur-
ing adapter (accessory). Connect terminal L1 (black) from the adapter to
the mains phase and terminal L3 (PE) to the mains neutral conductor.
Now perform a "loop measurement". Line impedance (internal system
resistance) is displayed as a result of this measurement.
In order to assure that the PC software (e.g. PS3) does not recognize this
procedure as a Z measurement, but rather as a Z
Loop
enter the ! symbol as the first character in the comment line after the value
has been saved to memory (see chapter 4.5, page 15), for example !Out-
let 12.
28
can be determined with the
Loop
key. The table shows maximum allowable
measurement,
i
GMC-I Messtechnik GmbH