Guardian Technologies 4760, 4456, 4390 AC Generator, ENGINE-GENERATOR Drive System, Rotor Assembly

SECTION 2.1

DESCRIPTION & COMPONENTS

PART 2

AC GENERATORS

INTRODUCTION

The air-cooled, pre-packaged automatic standby system is an easy to install, fully enclosed and self- sufficient electric power system. It is designed especially for homeowners, but may be used in other applications as well. On occurrence of a utility power failure, this high performance system will (a) crank and start automatically, and (b) automatically transfer electrical loads to generator AC output.

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

directly coupled to the engine crankshaft (see Figure 1), and mounted in an enclosure. Both the engine and generator rotor are driven at approximately 3600 rpm, to provide a 60 Hz AC output.

THE AC GENERATOR

Figure 1 shows the major components of the AC generator.

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

A2-pole, "V-Type", prepackaged transfer switch is shipped with the unit (see Part 3). Prepackaged transfer switches do not include an "intelligence circuit" of their own. Instead, automatic startup, transfer, running, retransfer and shutdown operations are controlled by a solid state circuit board in the generator control panel.

ENGINE-GENERATOR DRIVE SYSTEM

The generator revolving field is driven by an air- cooled, horizontal crankshaft engine. The generator is

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 assembly 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. 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.

Figure 1. AC Generator Exploded View

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