Gossen MetraWatt SECULIFE ST BASE 25, Руководство по эксплуатации

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58 Gossen Metrawatt GmbH
15.8.2 Touch Current – IT
Application
Make sure that the contacted parts are not inadvertently
grounded.
Definition
Current which flows from housing parts which are not connected
to the protective conductor via an external conductive connection
to earth or another part of the housing. Flow of current via the
protective conductor is excluded in this case.
The following designations are also common:
housing leakage current, probe current.
Direct measuring method
–
Measurement type: direct P1
– DUT mains plug to test socket
– Test probe P1 to P1 terminals
Schematic Diagram
The device under test is operated with mains power. Current
which flows to the protective conductor via exposed conductive
parts and via the probe is measured. The measurements must be
performed with mains plug polarity in both directions. Switching
takes place via the polarity softkey. The RMS, the AC or the DC
component of the current is measured.
Wiring Diagram
Note
Regarding protection class I DUTs:
Parts may or may not be grounded.
Coincidental grounding only occurs in the event of an
error.
Differential Current Method
–
Measurement type differential P1
– DUT mains plug to test socket
– Test probe P1 to P1 terminals
Schematic Diagram
The device under test (PCII) is operated with mains power. Differ-
ential current which flows via the two mains conductors is mea-
sured (current clamp measurement concept). The measurements
must be performed with mains plug polarity in both directions.
Switching takes place via the polarity softkey. The current’s AC
component is measured. Accessible conductive parts must be
contacted with test probe P1.
Note
Only use the differential current method in order to deter-
mine touch current at PC II DUTs
(in the case of PC I DUTs, the measured value includes
full protective conductor current as a result of the mea-
suring method).
Wiring Diagram
Single Measurements, Rotary Switch Level: Green
Ro
ta
ry
Swi
tc
h
Po
si
ti
o
n
Meas. Type
With Mains
to Test
Socket Meas. Type
Without
Mains to Test
Socket Measuring Functions
I
T
Direct P1
I
T
Touch current, RMS
I
T ~
AC component
I
T=
DC component
U
LN
Test voltage
Differential P1
I
T
Touch current, RMS
U
LN
Test voltage
Alternative P1
I
T
Touch current, RMS
U Test voltage
Perm. conn. P1
I
T
Touch current, RMS
I
T ~
AC component
I
T=
DC component
Alternative
P1–P2 I
T
Touch current, RMS
U Test voltage
I
T