13.11
Date Code 20080213 Instruction Manual SEL-351A Relay
Testing and Troubleshooting
Relay Troubleshooting
Relay Troubleshooting
Inspection Procedure
Complete the following procedure before disturbing the relay. After you finish
the inspection, proceed to the Troubleshooting Procedure.
Step 1. Measure and record the power supply voltage at the power
input terminals.
Step 2. Check to see that the power is on.
Do not turn the relay off.
Step 3. Measure and record the voltage at all control inputs.
Step 4. Measure and record the state of all output relays.
Troubleshooting
Procedure
All Front-Panel LEDs Dark
1. Input power not present or fuse is blown.
2. Self-test failure.
Cannot See Characters on Relay LCD Screen
1. Relay is de-energized.
Check to see if the ALARM contact is closed.
2. LCD contrast is out of adjustment. Use the following steps to
adjust the contrast.
a. Remove the relay front panel by removing the six front-
panel screws.
b. Press any front-panel pushbutton. The relay should turn
on the LCD back lighting.
c. Locate the contrast adjust potentiometer adjacent to the
serial port connector.
d. Use a small screwdriver to adjust the potentiometer.
e. Replace the relay front panel.
Relay Does Not Respond to Commands From Device Connected to Serial
Port
1. Communications device not connected to relay.
2. Relay or communications device at incorrect baud rate or other
communications parameter incompatibility, including cabling
error.
3. Relay serial port has received an XOFF, halting
communications. Type <CTRL> Q to send the relay an XON
and restart communications.
Relay Does Not Respond to Faults
1. Relay improperly set.
2. Improper test source settings.
Courtesy of NationalSwitchgear.com
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