Operating the Generator Set
The procedures for operating a single generator set
(single unit) are as follows:
1. Ensure that the PARALLEL OPERATION-
SINGLE UNIT OPERATION switch (fig. 3-19) is set
to SINGLE UNIT OPERATION.
2. Position the AMPS-VOLTS selector switch to
the required position. Rotate the VOLTAGE ADJUST
control to obtain the required voltage. Read the voltage
from the VOLTS AC meter.
3. Depress the locking button, and slide the
ENGINE MANUAL SPEED CONTROL in or out to
obtain the approximate rated frequency; rotate the
vernier knob (the knob on the control) clockwise or
counterclockwise to obtain the rated frequency.
NOTE: If necessary, the load may be applied
4. Operate the engine for at least 5 minutes to
warm it up.
5. Apply the load by holding the CKT BRK
switch (on the CONTROL CUBICLE) to CLOSE until
the CKT BRK indicator lights go out. Then release the
6. Observe the readings from the VOLTS AC
meter and the HERTZ (FREQUENCY) meter. The
voltage readings should be 120/208 to 240/416 volts ac
(depending on the positions of the AMPS-VOLTS
select switch and the voltage change board). Lets say,
for example, that you positioned the voltage change
board for 120/208 volts before you started the generator
set. When you position the AMPS-VOLTS selector
switch to L2-L0 VOLTS/L2 AMPS while the generator
is operating, the VOLTS AC meter should indicate 120
volts. The PERCENT RATED CURRENT meter will
indicate the percent rated current (not more than 100
percent) between generator line 2 and neutral. The
HERTZ (FREQUENCY) meter should indicate 50 or
60 hertz. The KILOWATTS meter should indicate no
more than 100 percent with the HERTZ
(FREQUENCY) meter showing 60 hertz. Readjust the
voltage and frequency, if necessary.
7. Observe the KILOWATTS meter. If the meter
indicates that more than the rated kilowatts are being
consumed, reduce the load.
8. Rotate the AMPS-VOLTS selector switch to
each phase position and monitor the PERCENT
RATED CURRENT meter. If more than the rated load
is indicated for any phase position, reduce or
reapportion the load.
9. Periodically (not less than once per hour),
monitor the engine and generator indicators to ensure
their continued operation.
10. Perform any during operation preventive
checks according to your checklist.
When in operation, the generator set should be
monitored periodically (at least once an hour) for signs
indicating possible future malfunctions.
After the warmup, the lubricating oil pressure
should remain virtually constant. Check and record the
level of lubricating oil while the engine is running
normally. If any significant changes occur in the oil
pressure, notify the maintenance personnel. Check and
record the coolant temperature of the normally running
engine. Notify maintenance personnel if the coolant
temperature changes significantly.
Learn the sounds of a normally running generator
set so that any unusual sounds indicating the possible
start of a malfunction may be detected early enough to
avoid major damage.
Stop the operation immediately if a deficiency that
woulddamage the equipment is noted during operation.
OPERATING PROCEDURES FOR
This section will include procedures for paralleling
generators, removing a set from parallel operations, and
stopping generator set operation.
NOTE: These procedures assume that one
generator set is on line (operating and connected to the
distribution feeder lines through the switchgear). The
set that is to be paralleled is designated the incoming set
When you are operating generator sets in
parallel, they must have the same output
voltage, frequency, phase relation, and phase
sequence before they can be connected to a
common distribution bus. Severe damage may
occur to the generator sets if these requirements
are not met.
Adjusting the engine speed of the incoming set
while observing the output frequency and the