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Operation
2.7
PROTECTION SYSTEMS
The engine has several safety switches that cause it to automati-
cally shut down, under the following conditions: low oil pressure,
high coolant temperature, and engine overspeed. See Figure 2.2
for the location of these devices. If automatic shutdown does
occur, refer to "Troubleshooting Guide".
2.7.1
LOW OIL PRESSURE SWITCH
This switch is normally closed (N.C.) but is held open by engine
oil pressure during engine running. Should operating oil pressure
drop below approximately 10 psi, the switch contacts close, and
the engine shuts down automatically.
2.7.2
HIGH COOLANT TEMPERATURE SWITCH
This normally-open (N.O.) thermostatic switch has a sensing tip
that is immersed in captive coolant. Should the coolant tempera-
ture exceed approximately 115° C (240° F), the switch contacts
close, and the engine shuts down automatically.
Figure 2.2 – Engine Protective Devices
2.7.3
OVERSPEED SHUTDOWN
A DC control circuit board senses engine speed from the frequency
of the alternator AC output. Should the alternator output frequency
exceed approximately 72 Hertz (4,320 alternator rpm), circuit
board action initiates an automatic engine shutdown.
2.7.4
OVERVOLTAGE PROTECTION
A solid-state voltage regulator (Figure 2.3) controls the generator's
AC output voltage. This regulator supplies an excitation current to
the rotor. By regulating the rotor's excitation current, the strength
of its magnetic field is regulated and, in turn, the voltage delivered
to connected electrical loads is controlled. When the AC frequency
is 60 Hertz, voltage is regulated at 120 volts (voltage-to-frequency
ratio is 2-to-1).
10
Figure 2.3 – Solid-state Voltage Regulator
The voltage regulator also incorporates a "voltage surge protection
circuit." This circuit prevents troublesome surges in the generator
AC output voltage. Voltage surge is a common cause of damage
to electronic equipment.
2.8
ADDITIONAL INFORMATION
2.8.1
ATTENTION REQUIRED AFTER SUBMERSION
If the recreational vehicle generator has been submerged in water,
it MUST NOT be started and operated. Following any submersion
in water, have an Authorized Service Dealer thoroughly clean and
dry the generator.
2.8.2
OPERATION IN HIGH GRASS OR BRUSH
Never operate the generator while the vehicle is parked over high
grass, weeds, brush, leaves, or other combustible substance.
Such materials can ignite and burn from the heat of the exhaust
system. The generator exhaust system becomes extremely hot
during operation and remains hot for a long time after it has shut
down.
2.8.3
EFFECTS OF MOISTURE AND DIRT
Keep the generator set as clean and dry as possible. Protect the
unit against excessive dust, dirt, corrosive vapors, road splash,
etc. Permitting dirt and moisture to accumulate on generator
windings will have an adverse effect on the insulation resistance
of those windings.
When moisture is allowed to remain in contact with windings,
some of the moisture will be retained in voids and cracks in the
insulation. This reduces insulation resistance and will eventually
cause problems. Dirt will make the problem worse, since it tends
to hold moisture in contact with windings. Salt (as from sea air)
will also worsen the problem, since it tends to absorb moisture
from the air. Salt and moisture, when combined, form a good
electrical conductor.
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