Guardian Technologies 004270-3 - Manual (Page 12)

10 Generac ® Power Systems, Inc.
Section 2 – Operation
QUIETPACT™ 75D Recreational Vehicle Generator
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 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-1).
Figure 2.3 – Solid-state Voltage Regulator
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.
• 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 pis-
ton rings, resulting in blowby and high oil con-
sumption.
• Check the engine oil level frequently. Add oil if
needed. It is normal for the generator engine to
consume more oil than normally, until the piston
rings have properly seated.
2.8.2 25-HOUR CHECK-UP
After the 25-hour break-in period, contact a Generac
Authorized Service Dealer for the following mainte-
nance, for which the vehicle owner is responsible for
all charges:
• Change the engine crankcase oil and oil filter.
• Check all fluid levels (engine coolant, fuel,
battery electrolyte fluid).
• Visually inspect the unit for any leaks or loose
hardware.
• Inspect the exhaust tailpipe for any leaks or
damage.
2.8.3 ATTENTION REQUIRED
AFTER SUBMERSION
If the recreational vehicle generator has been sub-
merged in water, it MUST NOT be started and oper-
ated. Following any submersion in water, have a
Generac Authorized Service Dealer thoroughly clean
and dry the generator.
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