Generac Power Systems 9344-2 - Manual (Page 9)

ADDITIONAL INFORMATION
AUTOMATIC LOW OIL PRESSURE
SHUTDOWN
The engine is equipped with a normally-closed (N.C.) oil
pressure switch (Figure 6). Engine oil pressure holds
the switch open during cranking and operation. Should
oil pressure drop below about 10 psi, the switch con­
tacts close and the engine automatically shuts down.
Figure 6 — Low Oil Pressure Switch
HIGH COOLANT TEIVIPERATURE SHUTDOWN
This switch (Figure 7) is a normally open (N.O.) ther­
mostatic device which is immersed in engine coolant.
Should
engine coolant temperature exceed about
250°F (121 °C), the switch contacts close and the
engine shuts down.
Figure 7 — High Coolant Temperature Switch
OVERSPEED SHUTDOWN
The generator control panel houses an Engine
Controller circuit board (Figure 8). That circuit board
receives AC frequency signals from generator stator
leads 11 and 22. Should AC frequency exceed about
72 Hz (2160 rpm), circuit board action initiates an auto­
matic shutdown after a few seconds.
Figure 8 — Engine Controller Circuit Board
NOTE: After an overspeed shutdown, the engine may
be cranked and re-started. However, if the engine
overspeeds again, the engine will shut down again.
ENGINE GOVERNED SPEED
The generator is equipped with a 4-pole revolving field
(rotor) which must be driven at 1800 rpm to produce
the unit’s rated AC frequency of 60 Hz. The diesel
engine governor was factory set to about 62 Hz. The
diesel engine governor was factory set to about 62 Hz.
(I860) at no-load. After installing it, the installation
technician should check and adjust the governed
speed. Setting the no-load frequency slightly high
helps prevent excessive frequency, rpm and voltage
droop under heavy electrical loading.
DANGER: Do not tamper with the engine governor
settings. Excessively high engine speeds are dan­
gerous and increase the risk of personal injury and
damage to equipment an/or property. Excessively
low speeds impose a heavy load on the engine when
adequate engine power is not available and may
shorten engine life. The generator supplies correct
rated frequency and voltage only at the proper
speed. Some electrical devices may be damaged by
incorrect frequency and/or voltage. If engine speed
appears to be incorrect, contact your nearest autho­
rized service facility.
25-HOUR BREAK-IN PERIOD
The first 25 hours of operation is the break-in period for
the generator. Properly breaking in the generator is
essential to reducing oil consumption and enhancing
engine
performance. During the break-in period,
observe the following rules:
• For the first 25 hours, run the generator at varying electri­
cal loads, to help set the engine piston rings properly.