Schweitzer Engineering Laboratories SEL-701 - Page 237

Date Code 20010719 701 Motor Protection Relay
Maintenance & Troubleshooting
Self-Testing
10.5
Table 10.2 Relay Self-Tests (Continued)
Self-Test Description Limits
Protection
Disabled
on Failure
ALARM
Output
on Failure
Front-Panel
Message
on Failure
Micro-
processor
Crystal
Monitors the
microprocessor
crystal.
Yes Latched CLOCK
STOPPED
Micro-
processor
The micro-
processor
examines each
program
instruction,
memory access,
and interrupt.
Test fails
on detec-
tion of an
invalid
instruction,
memory
access, or
spurious
interrupt.
Yes Latched VECTOR nn
Clock
Battery
Measures the
real-time clock
battery voltage.
Battery
Voltage
<2.50 V
No Pulsed
Real-Time
Clock
Verifies the real-
time clock chip
communication,
time-keeping,
and memory
functions.
No Pulsed
Learned
Cool Time
Verifies the
relay’s ability to
learn the motor
cooling time.
Unable to
write data
to target
address
No Pulsed
Learned
Thermal
Capacity
to Start
Verifies the
relay’s ability to
learn the motor
thermal capacity
to start.
Unable to
write data
to target
address
No Pulsed