Generac Power Systems 4270-0 - Manual (Page 12)

OPERATION
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Section 2 - Operation
QUIETPACT™ 75D Recreational Vehicle Generator
Figure 2.2 - Engine Protective Devices Figure 2.3 - Soiid-state Voitage Regulator
♦ 2.7.3 OVERSPEED SHUTDOWN_________________
The DC control circuit board (inside control panel)
senses engine speed from the frequency of the alter­
nator AC output. Should the alternator output fre­
quency exceed approximately 72 Hertz (4,320 alter­
nator rpm), circuit board action initiates an automat­
ic engine shutdown.
♦ 2.7.4 OVERVOLTAGE PROTEQION
A solid-state voltage regulator (Figure 2.3) controls
the generator’s AC output voltage. This regulator sup­
plies an excitation current to the rotor. By regulating
the rotor’s excitation current, the strength of its mag­
netic field is regulated and, in turn, the voltage deliv­
ered 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-l).
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The voltage regulator also incorporates a “voltage
surge protection circuit.” This circuit prevents trou­
blesome surges in the generator AC output voltage.
Voltage surge is a common cause of damage to elec­
tronic equipment.
2.8 ADDITIONAL INFORMATION
• 2.8.1 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 minimize oil consumption and maxi­
mize engine performance. During this 25-hour break-
in period, observe the following rules:
• Run the unit at varying electrical loads to help seat
the engine piston rings properly.
• After operating the unit for 25 hours, complete
the tasks recommended under Section 2.8.2
(Page 11).
• For the next 75 hours of operation following the
break-in period, avoid light electrical loads. Load
the generator at 50 percent (or more) of its rated
wattage
capacity. Repeated light loads during
these 75 hours can cause improper seating of
engine piston rings, resulting in blowby and high
oil consumption.
• Check the engine oil level frequently. Add oil if
needed. It is normal for the generator engine to
consume more oil than is normal until the piston
rings have properly seated.
i O Generac* Power Systems, Inc.