Manual

90 Gossen Metrawatt GmbH
19.8 Testing Residual Current Monitors
– RCM Function ( PROFITEST MXTRA only)
General
Residual current monitors (RCMs) monitor residual current in elec-
trical systems and display it continuously. As is also the case with
residual current devices, external switching devices can be con-
trolled in order to shut down supply power in the event that a
specified residual current value is exceeded.
However, the advan-
tage of an RCM is that
the user is informed of
fault current within the
system before shutdown
takes place.
As opposed to individual
measurement of I
N
and
t
A
, measurement results
must be evaluated man-
ually in this case.
If an RCM is used in
combination with an
external switching
device, the combination
must be tested as if it
were an RCD.
Connection
Set Parameters for I
F
Measure Touch Voltage
No-Trip Test with ½ × I
 N
and 10 s
After 10 seconds have elapsed, no residual current may be indi-
cated. The measurement must then be evaluated. In the event
that “NOT OK” is selected (in case of false alarm), an error is indi-
cated by the UL/RL LED which lights up red.
The measured value cannot be saved to memory and included in
the test report until it has been evaluated.
Tripping test with 1 × I
N
– Measurement of Signal Response Time (Stopwatch Function)
with Residual Current Generated by the Test Instrument
Measurement must be stopped manually by pressing the ON/
START ▼ or I
N
key immediately after indication of residual current,
in order to document tripping time.
In the event that NOT OK is selected, an error is indicated by the UL/
RL LED which lights up red.
The measured value cannot be saved to memory and included in
the test report until it has been evaluated.
Nom. res. current: 10 … 500 mA
Waveform:
Nominal current: 6 … 125 A
Type: A , B *
* Type B = AC/DC sensitive
X times tripping current:
Connection: with/without probe
System type: TN/TT, IT
Touch voltage:
< 25 V, < 50 V, < 65 V