Hobart 9OC24S Operation Manual page 205

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OPERATION, MAINTENANCE, AND OVERHAUL MANUAL, TM-240A
SELF-PROPELLED GENERATOR SET, SPEC. NO, 5381A
All fuel to the engine (iniectors) must pass through a shut-off valve, mounted on
the fuel pump. The valve is open only when energized by 12-V direct current
which is supplied through the engine control switch (6s) and a series of engine
shut-down safety switches.
Under normal operating conditions the shut-off valve
holding circuit is opened and the engine stopped by placing the engine control
switch (6s) in STOP position.
The actuation of any one of the safety switches,
caused byan abnormal operating condition such as low oil pressure, etc., will
oid circuit, allow the valve to close, and shut-off
ight (1G) glows when the engine circuit is energized.
open the shut-off valve sole,
71
engine fue I.
An indicating I
B. Safety Switch By-Pass
Since the oil pressure switch is OPEN when "at-rest", some arrangement for by-
passing it is necessary for starting the engine. A by-pass circuit direct to the shut-
off valve is provided through the START contacts of the engine control switch (6s).
The switch is spring-loaded in START position and must be manually held in this
position, at engine start-up, until the engine starts and oil pressure builds sufficient-
ly (12 PSI) to close the OIL PRESSURE SWITCH. Output cable plugs must be properly
stored in plug boxes (PBMS) to make the by-pass circuit functional.
C. Operating Mode Control System
This system provides 12-V DC power for operation of the electric governor control
box and the AC generator excitation-deenergization relay (EDR). The system
is protected by a 10 ampere fuse (1FU). An hourmeter (RTM) is connected to the
12-V system so that the meter operates only when the engine control switch (6s)
is in RUN (or START) position.
A two-position toggle switch (3s) is identified as the operating mode control switch,
When in GEN position, it serves to connect 12-V DC power to the governor
control box, the generator excitation-deenergization relay (EDR), and fuel valve
solenoid through thegearshift Micro switch (GSMS). Thus, any attempt to move
the vehicle by placing the transmission in gear will open the circuit and stop the
engine. In DRIVE
position the operating mode switch connects power only to the
fuel solenoid valve through the plug box switches (PBMS). The vehicle cannot be
operated in DR IVE unless output cables are disconnected and properly stored in
plug boxes.
(1) Electric-hydraulic governor system
(a) General
The electric-hydraulic governor system is primarily an electrical installa-
tion . The only hydraulic function performed is actuation of the mechanical
fuel control linkage through a piston and lever arrangement in the actuator.
Engine fuel pressure supplies the required hydraulic power.
Ott 30/73
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