Guardian Technologies 5308, 4582 & 4987 Introduction AC Generator, Engine-Generator Drive System

Section 3

DESCRIPTION & COMPONENTS

Introduction The AC Generator

The generator revolving field (rotor) is driven by an air-cooled engine at about 3600 rpm.

The generator may be used to supply electrical power for the operation of 120 and/or 240 volts, 1-phase, 60 Hz, AC loads.

Engine-Generator Drive System

The generator revolving field is driven by an air- cooled, horizontal crankshaft engine. The generator is directly coupled to the engine crankshaft (see Figure 1). Both the engine and generator rotor are driven at approximately 3600 rpm, to provide a 60 Hz AC out- put.

Figure 3-1 shows the major components of the AC generator.

Rotor Assembly

The 2-pole rotor must be operated at 3600 rpm to supply a 60 Hertz AC frequency. The term “2-pole” means the rotor has a single north magnetic pole and a single south magnetic pole. As the rotor rotates, its lines of magnetic flux cut across the stator assem- bly windings and a voltage is induced into the stator windings. The rotor shaft mounts a positive (+) and a negative (-) slip ring, with the positive (+) slip ring nearest the rear bearing carrier (Figure 3-2). The rotor bearing is pressed onto the end of the rotor shaft. The tapered rotor shaft is mounted to a tapered crankshaft and is held in place with a single through bolt.

STATOR

ROTOR

BRUSH HOLDER

ASSEMBLY

ENGINE

ENGINE

ADAPTOR

REAR BEARING

CARRIER

Figure 3-1. – AC Generator Exploded View

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