Synchronous Machine on Infinite Bus Bars: Synchronizing to Infinite Bus Bars – A definite procedure has to be followed in connecting a synchronous machine to bus-bars which for the present purpose will be assumed to be infinite. Infinite bus-bars means a 3-phase supply of constant voltage and frequency independent of the load exchanged (fed into the […]

### SYNCHRONOUS MACHINE

## Nature of Armature Reaction

Nature of Armature Reaction The nature of the armature reaction is dependent on the power factor at which the machine is operating and upon the operating mode-generating/motoring. For simplicity of explanation, it will be assumed here that the armature resistance and leakage reactance are negligible so that Figure 8.26 shows the phasor diagrams, with component […]

## Determination of Armature Reaction

Determination of Armature Reaction The simple circuit model of the synchronous machine was obtained in Sec. 8.3 by making the assumption that the magnetic circuit of the machine is linear. However, it is known that, under normal operating conditions, the machine operates in a somewhat saturated region. In order to take account of magnetic saturation […]

## Determination of the Synchronous Reactance

Determination of the Synchronous Reactance With the assumption of a linear magnetic circuit, the circuit model (per phase) of a synchronous machine is as given in Fig. 8.10c. If Ra is neglected, it then follows that It is immediately seen from Eq. (8.22) that for a given field current under short-circuit condition (/,„ = /so […]

## Circuit Model of Synchronous Machine

Circuit Model of Synchronous Machine Circuit Model of Synchronous Machine – By assuming linearity of the magnetic circuit, it is possible to obtain simple circuit model of the synchronous machine. The validity of this assumption stems from the fact that air-gap is the predominant component of the magnetic circuit of the machine. Approximate nonlinear analysis is […]

## Voltage Regulation

Voltage Regulation The voltage regulation of a synchronous generator is defined on lines similar to that of a transformer. Consider the generator supplying full-load current at a specified power factor and rated terminal voltage, V, (rated). As the load is thrown off keeping the field current constant, the terminal voltage rises to The percentage […]

## Realistic Machine

Realistic Machine: Realistic Machine – A realistic synchronous machine will have resistance ra and leakage reactance x1 per armature phase which can be assumed to be lumped in series between the terminal voltage V, and the air-gap emf Er for each machine phase. The circuit diagram of the machine on a per phase basis is […]

## Synchronous Machine Model and Its Basics

Synchronous Machine Model and Its Basics: Synchronous Machine Model and Its Basics – As stated above the cylindrical-rotor synchronous machine offers constant permeance to mmf waves irrespective of the mechanical position of the rotor and is, therefore, simpler to model. Figure 8.1 shows the cross-sectional view of a 2-pole* cylindrical-rotor synchronous machine. The rotor has […]

## Introduction to Synchronous Machine

Introduction to Synchronous Machine Introduction to Synchronous Machine – A synchronous machine is one of the important types of electric machines; in fact all generating machines at power stations are of synchronous kind and are known as synchronous generators or alternators. The structure and certain operational features of the synchronous machine have already been explained […]