# Synchronous Machines

## Synchronous Condensor

Synchronous Condensor is also known as Synchronous Compensator or Synchronous Phase Modifier. A synchronous condenser or a synchronous compensator is a synchronous motor running without a mechanical load. It can generate or absorb reactive volt-ampere (VAr) by varying the excitation of its field winding. It can be made to take a leading current with over-excitation …

## Zero Power Factor Characteristic (ZPFC)

Zero Power Factor Characteristic (ZPFC) of a generator is a curve of the armature terminal voltage and the field current. The machine is operated with a constantly rated armature current at synchronous speed and zero lagging power factor. The Zero Power Factor Characteristic is also called as Potier Characteristic. For maintaining a very low power …

## Potier Triangle or Zero Power Factor Method

The Potier triangle determines the voltage regulation of the machines. This method depends on the separation of the leakage reactance of armature and their effects. The graph of the Potier triangle is shown in the figure below. The triangle formed by the vertices a, b, c has shown below in the figure is called Potier …

## MMF Method of Voltage Regulation

MMF Method is also known as Ampere Turn Method. The synchronous impedance method is based on the concept of replacing the effect of armature reaction with an imaginary reactance, the Magnetomotive force (MMF). The MMF method replaces the effect of armature leakage reactance with an equivalent additional armature reaction MMF so that this MMF may …

## Excitation System of a Synchronous Machine

The word Excitation means the production of flux by passing current in the field winding. The arrangement or the system used for the excitation of the synchronous machine is known as Excitation System. To excite the field winding of the rotor of the synchronous machine, direct current is required. Direct current is supplied to the …

## Voltage Regulation of a Synchronous Generator

The Voltage Regulation of a Synchronous Generator is the rise in voltage at the terminals when the load is reduced from full load rated value to zero, speed and field current remaining constant. It depends upon the power factor of the load. For unity and lagging power factors, there is always a voltage drop with the …

## Synchronous Reactance and Synchronous Impedance

The Synchronous Reactance (XS) is the imaginary reactance employed to account for the voltage effects in the armature circuit produced by the actual armature leakage reactance and by the change in the air gap flux caused by the armature reaction. Similarly, the Synchronous Impedance ZS is a fictitious impedance employed to account for the voltage …

## Armature Winding

Armature Winding is the winding, in which voltage is induced. Field Winding is the winding in which the main field flux is produced when the current through the winding is passed. Some of the basic terms related to the Armature Winding are defined as follows: Turn: A turn consists of two conductors connected to one …

## Synchronous Generators

Definition: The synchronous generator or alternator is an electrical machine that converts the mechanical power from a prime mover into an AC electrical power at a particular voltage and frequency. The synchronous motor always runs at a constant speed called synchronous speed. Working Principle of Synchronous Generator The synchronous generator works on the principle of …

## Synchronous Speed

The synchronous speed is the speed of the revolution of the magnetic field in the stator winding of the motor. It is the speed at which the electromotive force is produced by the alternating machine. The Synchronous Speed is given by the relation shown below. The above equation (1) shows that the rotor speed N …