5-22 Control Logic Date Code 20010731
SEL-352-1, -2 Instruction Manual
52A Target LED
The relay illuminates the 52A target LED when all three breaker monitoring bits (52AA, 52AB,
52AC) assert. Figure 5.14 shows the 52A target LED logic.
Figure 5.14: 52A Target LED Logic
A, B, and C Target LEDs
The relay illuminates and latches the A, B, and/or C target LED to indicate which phases were
involved with the breaker failure. The failures during a FAULT, LOAD, FLASH, UBAL, and
THERM include phase indication. When one of these conditions exists according to Figure 5.15,
the phase(s) involved will target accordingly. A-phase logic is shown, but B and C are similar.
Figure 5.15: A-Phase Target LED Logic
These phase targets latch until the condition goes away and either the Target Reset button is
pushed or the TAR R command is issued to one of the serial ports.
MOD Target LED
The relay illuminates the MOD target LED when the motor-operated disconnect status element
(MODST) is asserted.
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