5-34. OVER VOLTAGE RELAY KIIO (63, Figure 5-9).
Inspect screw and captive washer assemblies (62) and electrical connections for security.
Inspect wires connected to over voltage relay K110 for evidence of burning or insulation breakdown.
Remove. See Figure 5-9.
Tag and disconnect wires from over voltage relay K110 terminals.
Remove over voltage relay K110 (63) by removing screw and captive washer assemblies (62).
Preparation for bench test.
Remove over voltage relay Kl0 in accordance with step b, above.
Obtain a 3 phase, O to 250 V ac variable power source with a built-in voltmeter, a multimeter (or a
relay tester) and a stopwatch.
If variable power source has no built in voltmeter, a separate 0-300 V ac voltmeter may be
connected across any two output lines of the three phase power source.
See Figure 5-29. Connect the 3 phase 250 V ac variable voltage source at terminals 1, 2, and 3 of
K110. Set multimeter to RX1 scale and connect across terminals 4 and 6 of the relay.
Turn on variable voltage source with voltage output set at zero and observe multimeter reading.
Multimeter at this point should read zero ohms.
Increase voltage into relay K10 while monitoring power source voltmeter and multimeter connected
at relay terminals 4 and 6. Relay contacts should trip at 239 ±5 V ac as indicated by multimeter
deflecting to infinite ohms. Record voltage trip point as indicated on voltmeter.
Turn off variable power source with voltage output level set at the trip point (239 ±5 V ac) recorded in
step (b), above, After 10 seconds turn variable voltage source back on while timing relay trip time
with a stopwatch. Relay should trip within 3 ±1 seconds as indicated by the multimeter needle
deflecting to infinite ohms (contacts open).
(a) If relay does not trip at the specified voltage (239 ±5 V ac), turn the trip voltage adjustment at the
upper left of the relay clockwise or counter clockwise to accordingly increase or decrease the over
voltage threshold level. Repeat step (2)(b), above, and continue adjusting until the desired 239 ±5 V
ac trip point is attained.
(b) If relay does not trip within the specified 3 ±l second time, turn the TIME RELAY adjustment on
the upper right of the relay clockwise or counterclockwise to increase or decrease the time delay.
Repeat step (2)(c), above, and continue adjusting until the specified 3 ii second time delay is
If specified over voltage threshold and/or time delay period cannot be attained through the relay
adjustment pots. Replace the over voltage relay Ki10.
Install. See Figure 5-9.
Install over voltage relay K110 (63) and secure with screw and captive washer assemblies (62).
Make wiring connections as tagged and discard tags.