ABB RED615 Technical Manual page 167

1YHT530004D05 D
615 series
Technical Manual
GUID-BCAA40B6-AFC8-439D-BFC6-754280F0000E-CN V1 EN
Figure 79: Logic diagram for phase selection module
When the Number of start phases 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. In case the fault disappears, the related timer-enabling signal is
removed.
When the setting is "2 out of 3" or "3 out of 3", the single-phase faults are not
detected. The setting "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 that are
controlled by common settings. This design allows true three-phase overcurrent
protection which is useful in some applications.
Common START and OPERATE outputs are created by ORing the phase-specific
start and operating outputs.
Each phase has its own phase-specific start and operating outputs: ST_A, ST_B,
ST_C, OPR_A, OPR_B and OPR_C.
Section 4
Protection functions
161