Benning ST 725 - Page 43

07/ 2018 BENNING ST 725
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- Otherwise, the measurement of the protective conductor resistance (R
PE
) will be started with
automatic polarity reversal and the highest measured value of both measurements will be
shown on the display.
- After the R
PE
test has been passed, the test of the protective conductor current I
LEAK
will be
carried out as permanent measurement for max. 30 seconds. Press the -key
7
to finish
early the measurement.
- If the protective conductor current is lower than the admissible limiting value, a will be
shown next to the I
LEAK
symbol.
- The overall test is considered to be passed, if "PASS" is shown on the display.
- When pressing the -key
7
without previously connecting the measuring adapter to the
BENNING ST 725, the following warning will be shown on the display:
Seegure7b: Testingofthree-phaseappliancesbymeansofactivemeasuringadapters(test
object placed on insulated surface)
Note:
- The protective conductor current measurement is carried out using a current transformer
in the protective conductor of the measuring adapter (044140 or 044141) and by means of
the direct measurement method. The test object must be placed onto an insulated surface.
No part of the test object must have a connection to the earth potential. Otherwise, leakage
currents to earth might influence the measuring result.
- If it is not possible to place the test object onto an insulated surface, the protective conductor
current measurement can be carried out alternatively by means of the differential current
measurement method using the BENNING CM 9 leakage current clamp (044065). For this,
the test object must be put into operation by means of the optional measuring adapters
(044127 or 044128) and all active conductors (L1, L2, L3 and N) must be clamped by means
of the leakage current clamp. The BENNING CM 9 measures the protective conductor
current by means of the differential current measurement method.