Eaton SEFELEC 5 Series, User Manual

Page: 86 / 209

User manual SEFELEC 5x Series 85 v1.06
SELECTION OF THE MODE OF CUT-OUT FAULT DETECTION
The device offers the possibility to choose between several modes of cut-out Fault detection
In the Delta I detection mode:
The ΔI (delta I) sensor automatically performs the subtraction between the
current flowing nor-
mally in the sample under test (I = U/Z) and the one that occurs suddenly when a fault occurs:
(I' = I + I fault).
In the IMAX detection mode:
The device continuously measures the current flowing in the sample under test and compares it
according to two possibilities:
- The high threshold (threshold IMAX) > 0, the low threshold (threshold IMIN) is set to 0
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If the measured current is greater than or equal to the threshold, the test is de-
clared FAIL (cut-out):
- The low threshold (IMIN threshold) > 0, the high threshold (threshold IMAX) is > low
threshold (IMIN threshold)
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If the current measured is inside of the range defined by the thresholds, the test is
PASS, if it is outside the range the test is declared FAIL (cut-out or I < IMIN).
The IMAX threshold may apply to the total current (capacitive and resistive) circulating in the
sample under test or only to the real current (resistive). The real current gives an indication of
the quality of the insulant tested without taking into account the current consumed by the capaci-
ty of this insulation.
The total current and the real current are linked by the formula:
𝑰𝑰𝑰𝑰𝑰𝑰𝑰𝑰𝑰𝑰𝑰𝑰 =
�𝑰𝑰𝑰𝑰𝑰𝑰𝑰𝑰𝑰𝑰 𝟐𝟐
+ 𝑰𝑰𝑰𝑰𝑰𝑰𝑰𝑰𝑰𝑰
𝟐𝟐
In the Delta I + IMAX detection modes:
In this case the IMAX and ΔI sensing modes are
active simultaneously
NOTE
In the mode without detection: In this case no current monitoring is per-
formed. And there is no adjustment of the output voltage in relation to the load