Protection Systems - Generac Power Systems 004702-0, 004703-0, 004704-0, 004705-0, 004706-0, 004707-0 Owner's Manual

2.7.2 DO NOT OVERLOAD THE GENERATOR
Read the rated wattage/amperage capacity of the gen-
erator on the generator data decal (see Section 1.1).
Applying electrical loads in excess of the unit's rated
capacity will cause the engine/generator to automati-
cally shut down.
To avoid overloading, add up the wattage of all con-
nected electrical lighting, appliance, tool and motor
loads. This total should not be greater than the
generator's rated wattage capacity.
• Most lighting, appliance, tool and motor loads
indicate their required watts on their nameplate or
data plate. For light bulbs, simply note the wattage
rating of the bulb.
• If a load does not show its rated wattage, multiply
that load's rated VOLTS times AMPS to obtain
WATTS.
• Induction type motors (such as those that run the
vehicle's furnace fan, refrigerator, air conditioner,
etc.) need about 2-1/2 times more watts of power
for starting than for running (for a few seconds
during motor starting). Be sure to allow for this
when connecting electrical loads to the genera-
tor. First, figure the watts needed to start electric
motors in the system. To that figure, add the run-
ning wattages of other items that will be operated
by the generator.
• Do not apply heavy electrical loads for the first two
or three hours of operation.
2.8

PROTECTION SYSTEMS

2.8.1 LOW OIL PRESSURE SWITCH
This switch (Figure 2.3) has normally closed (N.C.)
contacts that are held open by engine oil pressure
during cranking and operating. Should oil pressure
drop below a preset level, switch contacts close, and
the engine automatically shuts down. The unit should
not be restarted until oil is added.
10
Section 2 – Operation
Recreational Vehicle Generators
2.8.2 HIGH TEMPERATURE SWITCH
This switch (Figure 2.3), which has normally open
(N.O.) contacts, is mounted near the oil filter. The
contacts close if the temperature should exceed
approximately 270º F (132º C) for gasoline models,
and 284° F (140° C) for LP models, initiating an
engine shutdown.
Figure 2.3 – Low Oil Pressure and
High Temperature Switches
2.8.3 FIELD BOOST
The Controller Circuit Board houses a field boost
diode and resistor that are not part of the automatic
choke circuit. These two components are part of
a "field boost" circuit (Figure 2.4). During engine
cranking only, a positive DC (battery) voltage is deliv-
ered through a diode, resistor, brushes, slip rings,
and the generator rotor. Application of this voltage
to the rotor "flashes the field" whenever it is started.
Flashing of the field each time the generator starts
makes sure that a sufficiently strong magnetic field
is available to produce "pickup" voltage in the stator
windings.
Figure 2.4 – Field Boost Circuit