# Electrical Machines

## Advantages and Applications of an Induction Generator

In the previous article Induction Generator we have seen, What is an Induction Generator? And its torque-speed characteristic. Here we are now going to discuss the various advantages, disadvantages, and applications of the Induction Generator. Contents: Advantages of an Induction Generator Applications of an Induction Generator Limitation of an Induction Generator The induction machine is …

## Pole Amplitude Modulation Technique

The basic feature of Pole Amplitude Modulation (PAM) winding is the layout, which is irregular. The windings are divided into two parts. The two parts are either connected in series or parallel. The directions of current in the two halves are either the same or opposite. The process of the current reversal is equivalent to …

## Harmonics in an Induction Motor

Space harmonics fluxes are produced by the windings, slotting, magnetic saturation, inequalities in the air gap length. These harmonic fluxes induce voltages and circulate harmonic currents in the rotor windings. The interaction between the harmonic currents generated in the rotor and the harmonic fluxes results in the Harmonic torques, vibrations, and the noise. The air …

## Stator Voltage Control of an Induction Motor

Stator Voltage Control is a method used to control the speed of an Induction Motor. The speed of a three-phase induction motor can be varied by varying the supply voltage. As we already know that the torque developed is proportional to the square of the supply voltage and the slip at the maximum torque is …

## Slip Energy Recovery of an Induction Motor

Slip Energy Recovery is one of the methods of controlling the speed of an Induction motor. This method is also known as Static Scherbius Drive. In the rotor resistance control method, the slip power in the rotor circuit is wasted as I2R losses during the low-speed operation. The efficiency is also reduced. The slip power …

## Circle Diagram of an Induction Motor

The Circle Diagram of an Induction motor is very useful to study its performance under all operating conditions. The construction of the circle diagram is based on the approximate equivalent circuit shown below. It is the diagrammatic representation of the performance of the induction motor. The circle diagram provides information about the power output, losses, …

## Rotor Resistance Control of an Induction Motor

Rotor Resistance Control is also one of the methods by which we can control the speed of the Induction motor. The speed of the wound induction motor can be controlled by connecting an external resistance in the rotor circuit through slip rings. This method is not applicable to cage rotor induction motors. As we know …

## Speed Control of Induction Motor by Variable Frequency Control

Variable Frequency Control is a method that is used to control the speed of an induction motor. The synchronous speed and therefore, the speed of the motor can be controlled by varying the supply frequency. The synchronous speed of an induction motor is given by the relation shown below: The EMF induced in the stator …

## Speed Control of an Induction Motor

There is a various method of speed control of an Induction Motor. The rotor speed of an induction motor is given by the equation shown below. From equation (1) it is clear that the motor speed can be changed by a change in frequency f, a number of poles P, and slip s. Any one or …

## Pole Changing Method

Pole Changing Method is one of the main methods of the speed control of an induction motor. This method of controlling the speed by pole changing is used mainly for cage motor only because the cage rotor automatically develops a number of poles, which is equal to the poles of the stator winding. The number …