TM 5-6115-593-12
TO 35C2-3-463-1
lighting PARALLEL indicator lamp DS7 (K23
is held energized by self-latching contacts 5
and 6). With K23 energized, power is
applied (through K23 contacts 9, 10, 11, and
12) from power transformers T101 and T102
to the frequency paralleling circuit K106, DS
101, DS102, and K106 is a synchronizing
check relay which only allows the AC power
CKT BKR (CB2) to close to a dead bus or to
a
"synchronized"
energized
bus,
SYNCHROSCOPE M109. K106 is a
synchronizing check relay which only allows
the AC power CKT BKR (CB2) to close to a
dead bus or to a "synchronized" energized
bus.
Power transformer T102 senses the bus
voltage,
and
power
transformer
T101
senses
the
output
of
the
incoming
generator. SYNC light DS101 is connected
from the output terminal T101 to the output
terminal of T102. DS102 is similarly
connected across the remaining outputs.
The greater the frequency difference of the
generator sets, the greater the voltage
across the SYNC lights and the greater the
rate of which they will blink on and off. As
the
sets
approach
a
zero
frequency
difference,
the
lights
dim
and
finally
extinguish.
SYNCHROSCOPE
M109
performs essentially the same function and
also indicates relative frequency between
the generators to be paralleled. When
SYNCHROSCOPE
M109
points
to
12
O'clock, the generator is in sync with the
energized buss. If the droop (regulation)
characteristics of the separate generators
involved in parallel operation are different,
their ability to equally share the load is
diminished. To compensate for these
inherent differences in droop, REACTIVE
LOAD COMPENSATION CONTROL R104
allows the operator to offset the output
voltage of a particular generator. When
connected to a load, this generator will
droop to a voltage level that will enable
equal load sharing. Similar readings of each
generator set's AMMETER will reflect this
equal load sharing.
d.
Generator Faults. As a means of either
protecting the generator set and/or the load,
various fault-sensing devices have been
wired into the AC generator and control
circuit. All of the generator fault circuit
relays K32 through K36 and indicator lamps
DS32 through DS36, respectively, are
selflatching, that is, they will stay energized
even though the fault which caused them to
operate will no longer manifest itself when
the main contactors open. Therefore, when
a fault does occur, the crew should note
which fault indicator lamp is lit prior to
operating
the
ANNUNCIATOR
RESET
switch S14. Also when any fault occurs,
alarm horn Al will sound when relay K26
energizes and its normally open contacts
complete the 24-volt return of Al. Current
transformers are used in many of the
generator fault sensing circuits. The faults,
how they are monitored, and how damage is
prevented are described in the following
paragraphs:
(1)
Overvoltage Protection. If engine
speed were to become excessive or
voltage regulator VR101 malfunction,
the generator output voltage might
rise to a level harmful to either the
load,
the
generator,
or
engine
controls. To prevent this, overvoltage
relay K102 (connected across one of
the generator output windings) senses
when this occurs, and activates to
initiate the following sequence: K32
energizes (OVERVOLTAGE indicator
lamp DS32 lights); the engine fault
circuit
opens;
fuel
solenoid
L1
deactivates
(shutting
down
the
engine); and K1 deenergizes opening
the AC POWER CKT BKR (CB2)
(disconnecting the load).
(2)
Undervoltage
Protection.
It
is
possible that voltage regulator VR101
could malfunction in such manner as
to create an undervoltage condition
capable
of
damaging
the
load.
Connected
across
one
of
the
generator output windings, relay Kill
senses if the output voltage becomes
too
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