# Electrical Machines

## Hydrogen Cooling of a Synchronous Generator

Hydrogen Cooling or you can say hydrogen gas is used as a cooling medium in the generator casing because of its superior cooling properties. Certain mixtures of hydrogen and air are explosive. The explosion may take place with a range of 6 percent hydrogen and 94 percent air up to 71 percent hydrogen and 29 …

## Parallel Operation of the Alternators

Interconnection of the electric power systems is essential from the economical point of view and also for reliable and Parallel Operation. Interconnection of AC power systems requires synchronous generators to operate in parallel with each other. In generating stations, two or more generators are connected in parallel. The alternators are located at different locations forming …

## Synchronous Impedance Method

The Synchronous Impedance Method or Emf Method is based on the concept of replacing the effect of armature reaction with an imaginary reactance. For calculating the regulation, the synchronous method requires the following data; they are the armature resistance per phase and the open-circuit characteristic. The open-circuit characteristic is the graph of the circuit voltage …

## Infinite Bus

Definition: The bus whose voltage and frequency remain constant even after the variation in the load is known as the infinite bus. The alternators operating in parallel in a power system are the example of the infinite bus. The on and off of any of the alternators will not affect the working of the power …

## Construction of a Synchronous Machine

Construction of a Synchronous Machine, i.e. alternator or motor consists of two main parts, namely the stator and the rotor. The stator is the stationary part of the machine. It carries the armature winding in which the voltage is generated. The output of the machine is taken from the stator. The rotor is the rotating …

## Synchroscope Synchronizing

The Synchroscope is a device used for determining the phase angle differences between two or more machines at the time of the synchronization. The synchronization is essential for sharing the load on the bus bar of the power system. The following are the essentials conditions for synchronization: The magnitude of the incoming voltage becomes equal. …

## Flux Linkage Equation

The constant Flux Linkage concept is of considerable importance in studying alternator transients. This concept is stated as – The Flux Linkage after a sudden disturbance in a closed circuit having zero resistance and zero capacitance remain constant at their predisturbed values. There is no capacitance in the armature and the field windings of an …

## Working Principle of a Synchronous Motor

The stator and the rotor are the two main parts of the synchronous motor. The stator is the stationary part of the motor and the rotor is their rotating part. The stator is excited by the three-phase supply, and the rotor is excited by the DC supply. The term excitation means the magnetic field induces …

## 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 …