2.35
Date Code 20100129
Instruction Manual
SEL-751A Relay
Installation
Field Serviceability
Figure 2.37
Switchgear Application Example
Field Serviceability
The SEL-751A firmware may be upgraded in the field; refer to
for firmware upgrade instructions. You may
know when a self-test failure has occurred by configuring an output contact to
create a diagnostic alarm as explained in
Section 4: Protection and Logic
. By using the metering functions, you may know if the analog
front-end (not monitored by relay self-test) is functional. Refer to
for detailed testing and troubleshooting
information.
The only two components that may be replaced in the field are the power
supply fuse and the real-time clock battery. A lithium battery powers the clock
(date and time) if the external power source is lost or removed. The battery is a
3 V lithium coin cell, Ray-O-Vac
®
BR2335 or equivalent. At room
temperature (25°C), the battery will operate nominally for 10 years at rated
load. When the relay is powered from an external source, the battery
experiences a low self-discharge rate. Thus, battery life may extend well
beyond 10 years. The battery cannot be recharged.
3
2
1
LS2
LS3
LS3
LS1
LS1
LS2
Bus
LS1—LS4 are arc-flash detection inputs, point or bare-fiber sensors.
Equipment components are sensitive
to electrostatic discharge (ESD).
Undetectable permanent damage
can result if you do not use proper
ESD procedures. Ground yourself,
your work surface, and this
equipment before removing any
cover from this equipment. If your
facility is not equipped to work with
these components, contact SEL
about returning this device and
related SEL equipment for service.
!
CAUTION
Summary of Contents for 751A
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