Study On Induction Motor

Project and Seminar Material for Science Laboratory Technology SLT

Abstract

Induction motors are used in industrial control systems, as well as in main powered home appliances. Simple and rugged design, low cost, low maintenance and direct connection to an AC power source are the main advantages of induction motors. Various types of induction motors are avalaible in the market.

Different motors are suitable for different applications. Although induction motor are easier to design than DC motors,the speed and the torque control in various types of induction motors require a greater understanding of the design and the characteristics of these motors. This seminar discusses the basics of an induction motor, the different types, their characteristics, the selection criteria for different applications and basic control techniques.

Solar cell in other words called photovoltaic cell is the cell that generates electricity when light falls on it. As the word implies, photo means light, while voltaic means electricity. By the series and parallel electrically connection of these cells, a useful level of voltage and current can be achieved. When light falls on these cells, a certain portion of it is absorbed within the semi-conductor materials (cells).

The energy of the absorbed light mobilizes the electrons. The inbuilt electric field in the cells which is as a result of the doping method in the cells i.e the existence of holes and electrons in the cells, then causes the electrons to flow in a certain direction which is current in ampere. And by placing a metal contact on the top bottom of the cells the current together with voltage is drawn which can be used externally.

This project explains how solar cell can be formed using semi-conductor, say silicon type of solar cell which has terminal voltage of about 0.6v.

The chapter one gives a brief overview of what a semi-conductor material is, its conductivity and how it forms a solar cell (introductory part).

Chapter two treats the literature review of the write-up. It gives the history of solar cell technology.

Chapter three and four treats the main body of the write-up it explains how photovoltaic modules are made to achieve a useful level of voltage and current, the characteristics of a semi-conductor and their doping methods.

Chapter five is the conclusion/summary part of this work. The overview of advantages and disadvantages of solar cell module are treated.

Chapter One

1.0 Introduction

An induction or a synchronous motor is an AC electric motor in which the electric current in the rotor need to produce torgue is included by electromagnetic induction from the magnetic field of the stator winding. An induction motor there fore does not require mechanical commutation, separate excitation or self excitation for all or part of the energy transferred from stator to rotor, as in universal, DC and synchronous motors. An induction motors rotor can be either wound type or queerly cage type.

Three phase squirrel cage induction motors are widely used in industrial drivers because they are rugged, reliable and economical. Single phase induction motors are used extensively for smaller loads, such as house hold appliances like fans. Although traditionally used in fixed speed service, induction motors are increasingly bring used with variable frequency drives (VFDS) in variable speed service. VFDS offer especially important energy savings opportunities for existing and prospective induction motors in variable torque centrifugal fan, pump and compressor load applications. Squirrel cage induction motors are very widely used in both fixed speed and VFDS applications.

Formation of solar cell using semi-conductor material is the act of using a semi-conductor to build a cell that can generate electricity when light (photons) falls on it. In the field of electrical and electronics engineering a semi-conductor simply means those materials whose conductivity lies somewhere between that of pure conductors and insulators. They are neither good conductors nor good insulators at normal room temperature (25oc). They are insulators at very low temperatures and good conductors at high temperature. The Germanium (Ge) and silicon (Si) elements are the most important semi-conductor used in electronics.

A pure type of semi-conductor without doping is called an intrinsic semi-conductor, while extrinsic semiconductor is the one with doping. Where doping is the intentional addition of impurities to semi-conductors so as to increase its conductivity. For instance using silicon. When a silicon is doped with boron the resulting type is P-type, while if with phosphorous the resulting type is N-type. Hence solar cell has two parts the N-type and P-type side. And without this electric field, the cell would not work and this field forms when the N-type and P-type silicon are in contact.

Hence the electrons form the N-type side will rush to fill up the hole in the P-type side. Then when light in form of photons falls on the solar cell the energy frees electrons-hole pairs, with the presence of the electric field the electrons are caused to flow in a particular direction. Hence electric current is provided and the cells electric field causes a voltage flow.

Chapter Three

Conclusion

The induction motor drive is the fastest growing segment of the motor control market. There are various reasons for this growth. They are:

Ease of programming
Low investment cost for development
Flexibility to add additional features with minimal increase in hardware cost.
Faster time to market
Same VFD for wide ranges of motors with different ratings.
Reduced total part count and hence, compact design.
Reliability of the end product
Ease of mass production
Ever decreasing cost of semiconductors due to advancement in fabrication technology
Energy efficient solution

Induction motor has positioned itself to target the motor control market, where our advanced designs, progressive process technology and industry leading product performance enable us to deliver decidedly superior performance over our competition , which includes the best of the industry. These products are positioned to provide a complete product solution for embedded control applications found throughout the consumer, automotive and industrial control markets. Induction motors are meeting the unique design requirements