10.13
Date Code 20080918
Instruction Manual
SEL-749M Relay
Testing and Troubleshooting
Troubleshooting
Troubleshooting
Refer to
for troubleshooting instructions for particular situations.
Factory Assistance
We appreciate your interest in SEL products and services. If you have
questions or comments, please contact us at:
Schweitzer Engineering Laboratories, Inc.
2350 NE Hopkins Court
Pullman, WA 99163-5603 USA
Phone: +1.509.332.1890
Fax: +1.509.332.7990
Internet:www.selinc.com
E-mail: [email protected]
Table 10.9
Troubleshooting
Problem
Possible Cause
Solution
The relay
ENABLED
front-panel LED is
dark.
Input power is not present or a fuse is
blown.
Verify that input power is present.
Check fuse continuity.
Self-test failure.
View the self-test failure message on the
front-panel display.
The relay front-panel display does not
show characters.
The relay front-panel has timed out.
Press the
{ESC}
pushbutton to activate the
display.
The relay is de-energized.
Verify input power and fuse continuity.
The relay does not accurately measure
voltages or currents.
Wiring error.
Verify input wiring.
Incorrect CTR1, CTRN, or PTR setting.
Verify instrument transformer ratios, con-
nections, and associated settings.
Voltage neutral terminal (N) is not prop-
erly grounded.
Verify wiring and connections.
The relay does not respond to commands
from a device connected to the serial port.
Cable is not connected.
Verify the cable connections.
Cable is not the correct type.
Verify the cable pinout.
The relay or device is at an incorrect baud
rate or has another parameter mismatch.
Verify Device software setup.
The relay serial port has received an
XOFF, halting communications.
Type
<Ctrl+Q>
to send the relay XON
and restart communications.
The relay does not respond to faults.
The relay is improperly set.
Verify the relay settings.
Improper test source settings.
Verify the test source settings.
Current or voltage input wiring error.
Verify input wiring.
Failed relay self-test.
Use the front-panel
RELAY STATUS
func-
tion to view self-test results.
Summary of Contents for SEL-749M
Page 6: ...This page intentionally left blank Courtesy of NationalSwitchgear com ...
Page 14: ...This page intentionally left blank Courtesy of NationalSwitchgear com ...
Page 20: ...This page intentionally left blank Courtesy of NationalSwitchgear com ...
Page 32: ...This page intentionally left blank Courtesy of NationalSwitchgear com ...
Page 52: ...This page intentionally left blank Courtesy of NationalSwitchgear com ...
Page 118: ...This page intentionally left blank Courtesy of NationalSwitchgear com ...
Page 188: ...This page intentionally left blank Courtesy of NationalSwitchgear com ...
Page 216: ...This page intentionally left blank Courtesy of NationalSwitchgear com ...
Page 224: ...This page intentionally left blank Courtesy of NationalSwitchgear com ...
Page 274: ...This page intentionally left blank Courtesy of NationalSwitchgear com ...
Page 286: ...This page intentionally left blank Courtesy of NationalSwitchgear com ...
Page 306: ...This page intentionally left blank Courtesy of NationalSwitchgear com ...
Page 310: ...This page intentionally left blank Courtesy of NationalSwitchgear com ...
Page 314: ...This page intentionally left blank Courtesy of NationalSwitchgear com ...