Main Circuit Breaker; Engine Protective Devices - Generac Power Systems Guardian 004188-1 Owner's Manual

Model Rating
004188 15,000
004189 15,000
004370 20,000
004371 20,000
004474 25,000
004475 25,000
Gaseous fuels such as natural and LP (propane)
gas are highly explosive. Even the slightest
spark can ignite such fuels and cause an explo-
sion. No leakage of fuel is permitted. Natural
gas, which is lighter than air, tends to collect in
high areas. LP gas is heavier than air and tends
to settle in low areas.

ENGINE PROTECTIVE DEVICES

The engine has several safety switches which cause the
engine to automatically shut down under the following
conditions: low oil pressure, high coolant temperature,
engine overspeed, low coolant level or overcrank (Figure
1.3).
Figure 1.3 - Engine Protective Devices
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 about 8-10 psi (55-68
kPa), the switch contacts close and the engine shuts
down automatically (Figure 1.4).
Guardian Liquid-cooled 15 kW, 20 kW and 25 kW Generators
Figure 1.2 - Main Circuit Breaker
Phase Actual Current
1 62.5
1 62.5
1 83.3
1 83.3
1 104.2
1 104.2
* Amp Rating of C/B structured under model.
Section 1 - General Information
C/B Rating* % over rating
70
70
90
90
125
125
Figure 1.4 - Low Oil Pressure Switch
HIGH COOLANT TEMPERATURE SWITCH
Normally open (N.O.) thermostatic switch has sensing
tip which is immersed in captive coolant. Should
coolant temperature exceed about 230°F (110°C), the
switch contacts close, which causes the engine to shut
down automatically (Figure 1.5).
Figure 1.5- High Coolant Temperature Switch
LOW COOLANT LEVEL SWITCH
Should engine coolant level drop below the level of the
high coolant temperature switch, it is possible for the
engine to overheat without automatic shutdown.
prevent such overheating without automatic shut down,
the engine has a low coolant level sensor. If the engine
coolant drops too low, the engine automatically shuts
down (Figure 1.6).
Generac
Circuit Breaker
112% 70A BQ2
112% 70A BQ2
108% 90A BQ2
108% 90A BQ2
120% 125A BQ2
120% 125A BQ2
Power Systems, Inc.
®
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