4.1.10.2 Function block
Figure 177: Function block
4.1.10.3 Functionality
The loss of phase, undercurrent, protection function PHPTUC is used to detect an
undercurrent that is considered as a fault condition.
PHPTUC starts when the current is less than the set limit. Operation time
characteristics are according to definite time (DT).
The function contains a blocking functionality. It is possible to block function
outputs and reset the definite timer, if desired..
4.1.10.4 Operation principle
The function can be enabled and disabled with the
Operation setting
. The
corresponding parameter values are "On" and "Off".
The operation of PHPTUC can be described with a module diagram. All the modules
in the diagram are explained in the next sections.
Figure 178: Functional module diagram
Level detector 1
This module compares the phase currents (RMS value) to the
Start value
setting.
The
Operation mode
setting can be used to select the "Three Phase" or "Single
Phase" mode.
If in the "Three Phase" mode all the phase current values are less than the value of
the
Start value
setting, the condition is detected and an enable signal is sent to the
1MRS757644 H
Protection functions
620 series
Technical Manual
359
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