TM 5-6115-593-34
NAVFAC P-8-631-34
TO-35C2-3-463-2
Figure 17-9. Exhaust Fan
17-33. For electric generating sets that do not utilize
automatic starting provisions, manual shutters may be
used. A gravity drop shutter may be used for the
exhaust duct if the shutters are of light metal. When the
set operates, outlet air flow will open the shutter, which
closes automatically due to gravity when the unit is shut
down. Manual intake shutters operated by a pull chain
or pulley device must be opened to provide intake air.
The open-closing operation is a manual function.
17-34. For electric generating sets utilizing automatic
start functions, the use of motor-operated intake shutters
is recommended. The exhaust shutter may be of the
gravity drop type if the shutters are of lightweight
material. Motor-operated shutters are held closed by
spring tension and are driven to the open position by a
stall type motor operating through a mechanical linkage.
Care should be taken in wiring the system to ensure that
the intake shutter motor is supplied during all possible
modes of unit operation; i.e., true power failure,
simulated power failure due to incorporation of a system
test switch, or automatic plant exercising due to the
incorporation of a plant exercising timer.
17-35. Supplying the intake shutter motor from the
generator output (before any incorporated line circuit
breaker) will ensure its operation whenever the unit
operates. The shutter motor is usually of the
reconnectible type to accommodate either 110/220V AC
supplies. Special application transformers are available
to supply these values if the generator output does not
permit its use directly.
17-36. Thermal fusible links are available connected in
the motor circuitry to de-energize the motor and cause
the shutter to close in case of fire.
17-37. In some cold weather applications, the opening
of inlet shutters immediately on the starting may cause
carburetor icing, and vaporizing problems. Diesel
engines may not operate efficiently if extreme cold air is
admitted through fully open louvers. Thermostatically
controlled shutters can be used to counter the difficulties
inherent in cold weather applications.
Section VI. COOLING SYSTEM
17-38. A properly functioning cooling system is
extremely important to any internal combustion engine
since only a fractional part of the heat energy (fuel)
supplied to the engine is converted into useful work.
The excess heat of combustion is rejected in three
ways, by radiation to ambient air and engine oil, etc., via
the engine's exhaust system, and via the engine's
cooling system. See table 17-3.
17-39. LIQUID COOLING SYSTEM. The engine
utilizes a liquid coolant with jackets or chambers
surrounding each cylinder. Coolant water and engine
Table 17-3. Generator Set Heat Rejection, Radiator
Connections
Heat rejection to...................................564,900 BTU/HR
room by engine
generator
Heat rejection to................................1,368,000 BTU/HR
radiator by engine generator
Radiator inlet..................................................... 3 inches
(2) size
(7.62 cm)
Radiator outlet............................................. 3-1/2 inches
(8.89 cm)
Radiator water............................................ 210 gal./min.
flow
(13.25 liters/
sec.)
17-11
