Field Boost

Section 1

GENERATOR FUNDAMENTALS

When the engine is cranked during startup, the engine's starter contactor is energized closed. Battery current is then delivered to the starter motor and the engine cranks.

Closure of the starter contactor contacts also delivers battery voltage to Pin 13 of an Engine Controller cir- cuit board. The battery current flows through a 47 ohm, 2 watt resistor and a field boost diode, then to the Rotor via brushes and slip rings. This is called “Field Boost” current.

Field boost current is delivered to the Rotor only while the engine is cranking. The effect is to “flash the field” every time the engine is cranked. Field boost current helps ensure that sufficient “pickup” voltage is avail- able on every startup to turn the Voltage Regulator on and build AC output voltage.

NOTE: Loss of the Field Boost function may or may not result in loss of AC power winding out- put. If Rotor residual magnetism alone is suffi- cient to turn the Regulator on loss of Field Boost may go unnoticed. However, If residual magnet- ism alone Is not enough to turn the Regulator on, loss of the Field Boost function will result In loss of AC power winding output to the load. The AC output voltage will then drop to a value commen- surate with the Rotor's residual magnetism (about 7-12 VAC).

GENERATOR AC CONNECTION SYSTEM

These air-cooled generator sets are equipped with dual stator AC power windings. These two stator wind- ings supply electrical power to customer electrical loads by means of a dual 2-wire connection system.

You can use your generator set to supply electrical power for operating one of the following electrical loads:

•QUIETPACT 55G & LP: 120 and/or 240 volts, sin- gle phase, 60 Hz electrical loads. These loads can require up to 5500 watts (5.5 kW) of total power, but cannot exceed 45.8 AC amperes of current at 120 volts or exceed 22.9 AC amperes at 240 volts.

•QUIETPACT 65G & LP: 120 and/or 240 volts, sin- gle phase, 60 Hz electrical loads. These loads can require up to 6500 watts (6.5 kW) of total power, but cannot exceed 54.1 AC amperes of current at 120 volts or exceed 27 AC amperes at 240 volts.

•QUIETPACT 75G & LP: 120 and/or 240 volts, sin- gle phase, 60 Hz electrical loads. These loads can require up to 7500 watts (7.5 kW) of total power, but cannot exceed 62.5 AC amperes of current at 120 volts or exceed 31.2 AC amperes at 240 volts.

CAUTION! Do not overload the generator. Some installations may require that electrical loads be alternated to avoid overloading. Applying exces- sively high electrical loads may damage the gen- erator and may shorten its life. Add up the rated watts of all electrical lighting, appliance, tool and motor loads the generator will power at one time. This total should not be greater than the wattage capacity of the generator. If an electrical device nameplate gives only volts and amps, multiply volts times amps to obtain watts (volts x amps = watts). Some electric motors require more watts of power (or amps of current) for starting than for continuous operation.

Generators may be installed to provide the following outputs:

1.120 VAC loads only — one load with a maximum total wattage requirement equal to the generator’s rated power output (in watts), and 120V across the generator output terminals. Figure 1.8, page 7, shows the generator lead wire connections for 120VAC ONLY.

2.120/240 VAC loads — one load with a maximum total wattage requirement equal to the generator’s rated power output, and 240V across the generator output terminals; or two separate loads, each with a maximum total wattage requirement equal to half of the generator’s rated power output (in watts), and 120V across the generator output terminals. Figure 1.9 on page 7, shows the generator lead wire connections for 120/240 VAC loads.

LINE BREAKERS (120 VOLTS ONLY):

Protects generator’s AC output circuit against overload, i.e., prevents unit from exceeding wattage/amperage capacity. The circuit breaker rat- ings are as follows:

Model	Circuit Breaker 1	Circuit Breaker 2
QuietPact 55	30A	20A
QuietPact 65	30A	30A
QuietPact 75	35A	35A

Page 6

65, 75, 55 specifications

Generac Power Systems has established itself as a leader in power generation, offering a range of high-performance generators suited for residential and commercial applications. Among its lineup, the Generac 55, 65, and 75 kW generators stand out for their reliability, efficiency, and advanced features.

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Moving to the 65 kW model, it offers increased capacity while retaining the fundamental qualities of the 55 kW version. This unit is particularly suited for larger homes or commercial applications that require greater power demands. The 65 kW generator utilizes Generac’s G-Force engine, known for its durability and reduced maintenance needs. Advanced features such as remote monitoring capabilities allow users to check the generator's status from anywhere, providing peace of mind and convenience.

The 75 kW generator takes performance to the next level, making it ideal for even more significant power needs. It is engineered for both quiet operation and enhanced performance, accommodating a wide range of requirements from residential to larger commercial operations. The 75 kW model includes a full-load voltage regulation system that maintains stable power output under varying loads, safeguarding appliances and equipment.

All three models incorporate advanced air-cooled technology, which enhances their efficiency and operational lifespan. Additionally, their corrosion-resistant enclosures ensure durability even in harsh weather conditions, making them suitable for diverse environments. The intuitive LCD display on each unit provides critical information, including runtime hours and maintenance reminders, empowering users with easy access to the generator's performance data.

Overall, Generac Power Systems' 55, 65, and 75 kW generators represent a commitment to quality, reliability, and innovation in backup power solutions. They are designed to meet the demands of modern power consumption while ensuring peace of mind through robust engineering and advanced technology. Whether for home use or commercial applications, these generators provide an effective means to stay prepared for unexpected power outages.