ABB RED615 Technical Manual page 212

Section 4
Protection functions
206
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Figure 103: Logic diagram for phase selection module
When the Number of start phase setting is set to "1 out of 3" and the fault is in one
or several phases, the phase selection logic sends an enabling signal to the faulty
phase timers. If the fault disappears, the related timer-enabling signal is removed.
When the Number of start phase setting is "2 out of 3" or "3 out of 3", single-phase
faults are not detected. The value "3 out of 3" requires the fault to be present in all
three phases.
Timer A, Timer B, Timer C
The function design contains three independent phase-segregated timers which are
controlled by common settings. This design allows a true three-phase overcurrent
protection which is useful in some applications.
The common START and OPERATE outputs are created by "ORing" the phase-
specific starting and operating outputs.
1YHT530004D05 D
615 series
Technical Manual