read 20-32 VDC when the contactor switch
6-109. INSTALLATION. Refer to figure
S3 is placed to the clo se position.
6-22 and install the underfrequency relay
in the mode II relay box. Secure the re-
3. Measure the voltage from ter-
lay in position with four screw assemblies,
minal 8 of K11 to terminal board TB2-1.
The voltage should read 20-32 VDC with
wiring. Replace mode II relay box cover.
contactor switch to the close position; if
no voltage replace K11 relay. The under-
6-110. 400 HERTZ UNDERVOLTAGE
voltage relay should trip when the voltage
is lowered below 99 4 volts in 6 2
6-111. ON EQUIPMENT TEST.
a. Symptom and Isolation of Malfunc-
tag, then disconnect wiring to the under-
tion. A malfunction of the undervoltage
voltage relay. Remove the four screws
relay K11 is usually indicated by the illu-
securing the relay in position.
mination of the UNDERVOLTAGE fault
light, or by failure of the load contactor
6-112. BENCH TEST.
normal. To isolate the malfunction, pro-
ceed as follows:
a . Connect the undervoltage relay to
the test equipment as illustrated in
Exercise extreme care not to
touch exposed electrical connec-
tions when working inside mode
Exercise extreme care when
II relay box with generator set
making tests as high voltages
will cause injury to personnel
b. Energize variable voltage AC supply
Remove cover from mode II
and adjust to 120 VAC, 400 hertz. Ener-
relay box to gain access to
gize 24VDC supply and close switches S2
the test points, see figures
and S1. Indicator DS2 should energize and
6-15 and 6-22.
DS1 should deenergize.
c. Adjust the variable voltage supply
at rated speed and voltage, measure the
to 99 VAC. Indicator DS2 should de-
voltage from terminal 1 to terminal 2 of
energize and DS1 should energize after
the K11 relay. The nominal voltage is 120
6 2 seconds.
VAC. Remove the wire from terminal 3 of
K11 and reset fault light. If fault light can
d. If the undervoltage relay does not
now be reset, relay K11 is defective.
meet the requirements of the above test,
replace the relay.
2. If the voltage at terminals 1 and
2 is normal and the contactor CB2 won't
e. Remove the under voltage relay
close, measure the voltage from terminal
from the test equipment.
7 of K11 to TB2-1. The voltage should