2.27
Date Code 20170927 Instruction Manual SEL-751 Relay
Installation
AC/DC Control Connection Diagrams
The SEL-751 provides fail-safe and nonfail-safe trip modes (setting
selectable) for all output contacts. The following occurs in fail-safe mode:
➤ The relay coil is energized continuously if the SEL-751 is
powered and operational.
➤ When the SEL-751 generates a trip signal, the relay coil is de-
energized.
➤ The relay coil is also de-energized if the SEL-751 power supply
voltage is removed or if the SEL-751 fails (self-test status is
FAIL).
Figure 2.19 shows fail-safe and nonfail-safe wiring methods to control
breakers.
Figure 2.19 OUT103 Contact Fail-Safe and Nonfail-Safe Options
Nonfail-safe
OUT103FS = N
52A
Breaker Trip Coil
TC
A08
A07
A07
52A
Fail-Safe
(Electrically Held)
OUT103FS= Y
Circuit Breaker
Breaker Trip Coil
TC
A09