(when it senses this condition) opens
its normally closed contacts, thereby
deenergizing fuel solenoid L1.
Coolant Temperature. If the engine
coolant rises above 213 +3°F (100
+0.7°C), engine damage may occur.
operates to an open position when
this temperature becomes too high.
Low Fuel Level. In addition to the fact
that engine damage may occur, if the
engine ran completely out of fuel,
trying to restart the engine with a new
supply of fuel would require an
"bleeding" procedure. To avoid this,
fuel level switch FL1 is used to sense
when there is only enough fuel for one
more hour of engine operation and
shuts the engine down by deactivating
relay K8 (K8 contacts open the circuit
holding fuel solenoid L1 energized).
Engine Fault Indicators. If an engine fault
occurs, the engine will shut down and one of
several indicator lamps (mounted on the
Generator Control Panel) will light. In
annunciator (horn) will sound to alarm crew
members not in the immediate vicinity. To
ensure proper operation of these faults
indicators, a means whereby the lamps and
the annunciator may be tested is provided.
Since all of these circuits act in a similar
manner only one will be described.
If a high oil temperature condition exists, the
normally open contacts of switch OT2 will
close, applying +24-volts dc to energize
K28. Relay K28 is held energized by self-
latching contacts in parallel with OT2. At
this time ENG FAULT indicator lamp DS28
lights as 24V DC is applied to closed
contacts of S14, thermal fuse FC1, diode
CR30 through DS28, CR7, and relay
Coincident with this action relay K28
energizes (through normally closed contacts
S13, OT2 and K28) and as a result the horn
activates via normally open contacts K26
and normally closed contacts K25B.
When ANNUNCIATOR TEST switch S13 is
set to on, the horn is activated to its test
position through contacts 8 and 15 of S13.
To test indicator lamp DS28, -24V DC is
applied through contacts 7 and 4, diode
CR6, DS28, and back to +24V DC through
contacts 2 and 3 of S13 (the path consisting
of CR7 and K28 is disconnected from +24V
DC by open contacts 6 and 11 of S13).
Occasionally it may be beneficial to silence
SILENCE switch S12 to the on position.
With S12 on, relay K25A and K25B
energize. The contacts of K25A hold the
K25A and K25B coil energized when S12 is
released and the contacts K25B disconnect
the horn circuit. Operating ANNUNCIATOR
RESET switch S14 to on disconnects K25A
and K25B from -24V DC and re-enables the
Engine Operation. Once the engine is
running it is only necessary to monitor
various operating parameters and to vary
engine speed as required to set the
generator output frequency.
Engine Speed. Controlling engine
speed is achieved by varying engine
fuel intake by means of an electro
hydraulic governor. The operation of
determined by governor controller
FREQUENCY ADJUST switch S5 to
either INCREASE or DECREASE. S5
controls two-way motor B4 which is
electrically connected to A106 and
affects its operation.
Engine Monitoring. Located on the
Engine Control Panel are four gauges
M1 through M4 which, respectively,