TM 55-1930-209-14&P-1
m.
Close (ON) circuit breaker P8 (Figure 3-12) to provide power to power panel 2. Start void(s) 4 port and/or
starboard exhaust fans to provide ventilation in generator area. Close (ON) circuit breaker 9P8 for void 4
starboard ventilation and circuit breaker 10P8 for void 4 port ventilation (Figure 3-4).
3-7.5 Paralleling generators and transferring load
NOTE
These procedures can be done only while operating generators from switch-
board.
a.
Start new generator by following procedures in paragraphs 3-7.2 and 3-7.3, steps a thru i.
b.
Using AUTOMATIC VOLTAGE CONTROL RHEOSTAT (Figure 3-11), adjust voltage on new generator to a value
slightly higher than online generator.
c.
Switch INCOMING GENERATOR switch (Figure 3-14) to indicate incoming generator. This action allows
SYNCHROSCOPE to indicate frequency of incoming generator.
d.
Using GOVERNOR SPEED CONTROL switch (Figure 3-11), adjust frequency of new generator rotation so
SYNCHROSCOPE (Figure 3-14) either stops at the 12 o'clock position or turns very slowly in clockwise direction.
e.
If synchroscope pointer cannot be stopped at the 12 o'clock position, allow synchroscope to run slowly through
several complete rotations before performing step f below.
CAUTION
Before paralleling generators, notify crewmembers NOT to make any electrical
power changes such as turning any electrical motors on or off. Sudden power
surges while paralleling may cause a reverse power situation on one generator and
may damage that generator.
f.
Quickly and forcibly engage new generator circuit breaker (P1, P2, P3) (Figure 3-14) as synchroscope pointer is
stopped at 12 o'clock position or as it slowly passes through 11 o'clock position on synchroscope dial.
NOTE
If Incoming generator does not electrically match switchboard bus powered by
online generator, circuit breaker will forcibly bounce back to open. When this
happens, return to procedures in step 3-7.5b and try again.
g.
Turn SYNCHROSCOPE off by turning INCOMING GENERATOR switch to OFF (Figure 3-14).
CAUTION
Reverse power can occur when two generators are running in parallel. A generator
may not accept a load, usually because Its unloaded running speed is less than the
other generator (called speed droop). The other generator will motorize, or reverse
power, the drooping generator. This situation creates an undue load on the
powering generator and may damage the reverse powered generator.
h.
Transfer load from off going generator to oncoming generator by using AUTOMATIC VOLTAGE CONTROL
RHEOSTAT controls (Figure 3-11). Simultaneously increase load on oncoming generator by turning control
clockwise and decrease load of off going generator by turning control counterclockwise.
i.
Once off going generator load has been reduced to a minimum, open that generator's circuit breaker connecting it
to switchboard bus.
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