Generac Power Systems 004701-0 Additional Information, ‹ 2.8.2 High Temperature Switch

Section 2 – Operation

Recreational Vehicle Generator

‹2.8.2 HIGH TEMPERATURE SWITCH

This switch (Figure 2.2), which has normally open (N.O.) contacts, is mounted near the oil filter. The contacts close if the temperature should exceed approximately 284º F (140º C), initiating an engine shutdown.

Figure 2.2 – Low Oil Pressure and

High Temperature Switches

High Temperature Switch

Low Oil Pressure

Switch

‹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 2.3). During engine cranking only, a positive DC (battery) voltage is delivered through the diode, resistor, brushes and slip rings, to 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 2.3 – Field Boost Circuit

‹2.8.4 OVERVOLTAGE PROTECTION

A solid-state voltage regulator (Figure 2.4) 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 2.4 – 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.

2.9ADDITIONAL INFORMATION

‹2.9.1 25-HOUR BREAK-IN PERIOD

The first 25 hours of operation is the break-in period for the generator. Properly breaking in the genera- tor is essential to minimize fuel consumption and provide maximum engine performance. During this

25-hour break-in period, follow this procedure:

•Run the unit at varying electrical loads to help seat the engine piston rings properly.

•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.

•For the 75-hour operation following the break-in period, avoid light electrical loads. Load the gen- erator at 50 percent (or more) of its rated watt- age capacity. Repeated light loads during these 75 hours can cause improper seating of engine piston rings, resulting in blowby and high oil consump- tion.

•After operating the unit for 25 hours, complete the tasks recommended under "25-Hour Check-up".

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