Startco Engineering Ltd. Page 16
SE-325 Neutral-Grounding-Resistor Monitor Rev. 1
Pub. SE-325-M, May 6, 2008.
7.2 RESISTOR-FAULT TESTS
Perform tests with system de-energized and supply
voltage applied to the SE-325.
7.2.1 O
PEN TEST
Test Equipment: 20-kΩ and 100-kΩ, ¼-watt, 1% resistors
(included with SE-325).
Procedure:
• Remove connections to SE-325 R and G terminals.
• Connect the 20-kΩ resistor to R and G terminals.
• Set the RES switch to 20K.
• Press RESET.
• The RESISTOR-FAULT LED should be off.
• Remove the test resistor and wait 5 seconds
(20 seconds with Option S).
PASS: The SE-325 should trip on RESISTOR FAULT.
• Connect the 100-kΩ resistor to R and G terminals.
• Set the RES switch to 100K.
• Press RESET.
• The RESISTOR-FAULT LED should be off.
• Remove the test resistor and wait 5 seconds
(20 seconds with Option S).
PASS: The SE-325 should trip on RESISTOR FAULT.
To test the connected wiring, sensing resistor, and NGR:
• Reconnect SE-325 R and G connections.
• Set the RES switch to match sensing resistor.
• Press RESET.
PASS: The RESISTOR FAULT LED should be off.
7.2.2 V
OLTAGE TEST
Test Equipment: 0 to 120 Vac voltage source and multimeter.
N
OTE: Applying the test voltage to the R and G terminals will
damage the SE-325 and the ER sensing resistor. The RES
TRIP LEVEL is the trip voltage at terminal N, not terminal R.
Procedure:
• Check the ER sensing resistor connection to the SE-325.
• Disconnect the wire from sensing resistor terminal N.
• Set the voltage source to 0 V.
• Connect the voltage source between sensing resistor N and
G terminals.
• Set the RES TRIP LEVEL (VAC) to 20.
• Press RESET.
• The RESISTOR-FAULT LED should be off.
• Increase the test voltage to 25 Vac for 20-kΩ sensors or
120 Vac for 100-kΩ sensors and wait 5 seconds
(20 seconds with Option S).
PASS: The SE-325 should trip on RESISTOR FAULT.
7.3 S
ENSING-RESISTOR TEST
Test Equipment: Multimeter.
Procedure:
• Disconnect the sensing resistor.
• Measure the resistance between sensing-resistor terminals
R and N.
PASS: Resistance should be between 19.6 and 20.4 kΩ
for 20-kΩ sensing resistors. Resistance should be between
98 and 102 kΩ for 100-kΩ sensing resistors.
• Measure the resistance between sensing-resistor terminals
R and G in both directions.
PASS: Resistance should be greater than 10 MΩ in both
directions.
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