T . O . 35C2-3-442-2
P-9-TM-457-35
TM 5-6115-457-34
TM-07464A-35
CAUTION
2. Repeat step b. , reduce voltage
between 65 to 103 volts. The load contactor
If output contactor fails to open,
shall open in 6 2 seconds, causing the
instantaneously remove short
UNDER VOLT fault locator to illuminate.
circuit.
3. Repeat steps b. , 4. 1., and 4.2.
e. The output contactor shall actuate
two additional times.
instantaneously when current exceeds
425 25 percent of rated current, causing
10-11. UNDER FREQUENCY TRIP TEST
(PRECISE GENERATOR SETS
the SHORT CIRCUIT fault indicator to
illuminate.
ONLY).
10-10. OVER AND UNDER VOLTAGE
Perform the under frequency trip
TRIP TEST .
test as f ollows:
Perform the over and under voltage
a. Operate the generator set at no load,
trip tests as follows:
rated frequency, and rated voltage with load
contactor closed.
a. Connect a voltmeter between T9 and
T12 of the monitored 120 volt phase.
b. Lower frequency until the UNDER
FREQ fault locator indicator illuminates.
The load contactor should open, causing the
b. Operate the generator set at no load,
rated frequency, and rated voltage with load
UNDER FREQ fault locator indicator to
illuminate when the frequency drops to the
contactor closed.
values indicated below:
c . OVER VOLTAGE TRIP TEST.
50 hertz operation - 46 1 hertz
Raise voltage until the engine shuts down and
OVER VOLT fault locator indicator illumi-
60 hertz operation - 55 1 hertz
nates. Record the voltage. The over volt-
400 hertz operation - 370 5 hertz
age relay shall actuate when the voltage
exceeds 153 3 volts for more than
10-12. PHASE SEQUENCE CHECK.
200 milliseconds causing the load contactor
to open within 1 second, the engine to shut-
Perform the phase sequence check
down and the OVER VOLT fault indicator to
illuminate.
as follows:
a. Connect a suitable phase sequence
d. UNDER VOLTAGE TRIP TEST
indicator to generator set load terminals as
(PRECISE GENERATOR SETS ONLY),
following rotation of set.
1. Repeat step b. , lower voltage
b. Operate generator set and determine
until the UNDER VOLT fault locator indi-
phase sequence by observing the indicator.
The AC output connections shall be of the
c a t o r illuminates. Record voltage. The
load contactor shall open immediately when
proper rotation, compare test results with
the AC system simplified schematic, fig-
voltage drops below 48 volts, causing the
ure 1-4 for 50/60 hertz generator sets or
UNDER VOLT fault locator indicator to
illuminate.
10-4
