ARMY TM 9-6115-464-12
AIR FORCE TO 35C2-3-445-1
NAVY NAVFAC P-8-624-12
When generator sets are being operated in parallel, one or more operators
must remain with the sets to monitor the rated load and current meters.
Make further adjustments as required to maintain equal load on the paral-
leled sets. Equipment damage could result if caution is not observed.
Prior to removal of generator set from parallel operation, make sure the load
does not exceed the full load rating of set(s) remaining on line. Equipment
damage could result if caution is not observed.
(10) To remove a generator set from parallel operation, place the circuit breaker switch of that set in the
OPEN position. Stop the set as described in paragraph 2-7.
b. Parallel Operation (Load Transfer). The following method of parallel operation is to be used when it is
necessary to transfer the load from one set to the other without interrupting power.
Visually check that the power cable and parallel cable are in accordance with
Figure 2-6. If the cables are not attached as indicated, shutdown the on-line set
and follow instructions in paragraph 2-9.
Do not attempt load connects in paragraph 2-9b unless all sets are off and
no other external voltage Is applied to the load. Equipment damage could
result If caution is not observed.
The set in operation shall be designated as on-line and the sets placed in parallel operation shall
be designated on-coming.
Place the operations switch (26, Figure 2-1 ) on both sets in the PARALLEL OPERATION position.
Do not close the circuit breaker switch after starting the on-coming set as
serious damage to one or both generator sets may result. Equipment dam-
age could result if caution is not observed.
Refer to paragraph 2-6 and start the on-coming set. Do not perform steps 7 & 8 of Figure 2-8.
Note the voltage indicated on the on-line set. Adjust the voltage of the on-coming set to the volt-
age noted on the on-line set.
Adjust the frequency of the on-coming set to a higher value than that of the on-line set.
Slowly reduce the frequency of the on-coming set until the SYNCHRONIZING LIGHTS (25,
Figure 2-1 ) flash at 2 to 3 second intervals.
Do not place the circuit breaker switch of the on-coming set in the CLOSE
position while the SYNCHRONIZING LIGHTS are lit as damage to one or
both generator sets may result. Equipment damage could result if caution
is not observed.
Carefully watch the SYNCHRONIZING LIGHTS of the on-coming set. At the instant both lights go
dark, move the circuit breaker switch of the on-coming set to the CLOSE position.
Adjust the voltage and frequency rheostats of both sets until load and current are divided equally
between the two generator sets, as explained in paragraph 2-12a steps (7) and (8).
Move the circuit breaker switch (30) of the on-line set to the OPEN position.
Place the operations switch of the on-coming set to the SINGLE UNIT OPERATION position.
Readjust voltage and frequency of the on-coming set as necessary.
Refer to paragraph 2-7 and stop the on-line set.