b. Parallel Operation (Load Transfer). The follow-
(7) Carefully watch the SYNCHRONIZING
LIGHTS of the "on-coming" set. At the instant both
ing method of parallel operation is to be used when it
lights go dark, move the circuit breaker switch of the
is necessary to transfer the load from one set to the
"on-coming" set to the CLOSE position.
other without interrupting power.
(8) Adjust the voltage and frequency rheostats
of both sets until load and current are divided equal-
ly between the two generator sets, as explained in
Visually check that the power cable
and parallel cable are in accordance
(9) Move the circuit breaker switch (30) of the
attached as indicated, shutdown the
"on-line" set to the OPEN position.
"on-line" set and follow instructions
( 1 0 ) Place the operations switch of the "on-
not required with utility generator
coming" set to the SINGLE UNIT OPERATION
(11) Readjust voltage and frequency of the "on-
coming" set as necessary.
D o not attempt load connects in
and no other external voltage is ap-
plied to the load.
(1) The set in operation shall be designated as
"on-line" and sets placed in parallel operations shall
a. General. The diesel engine of a generator set on
be designated "on-coming".
standby service which is normally operated under op-
timum conditions should be exercised at least every
30 days. However, under any extreme environmental
both sets in the PARALLEL OPERATION position.
c o n d i t i o n , the interval between exercise periods
s h o u l d be shortened appropriately. The exercise
period should be long enough to enable the engine to
attain normal operating temperature.
b . Exercise Procedures.
Do not close the circuit breaker
switch after starting the "on-coming"
(1) Perform the before operation checks and ser-
set as serious damage to one or both
generator sets may result.
(3) Refer to paragraph 2-10 and start the "on-
(3) After allowing sufficient warm up time, run
the engine at full speed for the period of time required
(4) Note the voltage indicated on the "on-line"
t o obtain two consecutive collant temperature
set. Adjust the voltage of the "on-coming" set to the
readings at a 15 minute interval of 160F (71C)
voltage noted on the "on-line" set.
(5) Adjust the frequency of the "on-coming" set
(4) Allow the engine to run for an additional 30
to a higher value than that of the "on-line" set.
minutes while performing the during operation checks
(6) Slowly reduce the fre uency of the "on-
coming" set until the SYNCHRONIZING LIGHTS
(6) Perform the after operation checks and ser-
(7) Correct any deficiencies note during or after
Do not lace the circuit breaker
switch of the "on-coming" set in the
C L O S E position while the SYN-
C H R O N I Z I N G LIGHTS are lit as
damage to one or both generator sets