Design And Construction Of Induction Motor Protection And Monitoring System

ABSTRACT

Monitoring and protection system is needed in every industry to avoid unwanted faults in the process components that may leads to excessive downtime and huge losses in terms of maintenance cost and loss of revenue. Monitoring of induction motor parameters under various operating conditions plays a vital role in its performance, reliability, efficiency and life cycle. This research focuses on the design of a system for measuring and monitoring of voltage, stator current and winding temperature of an induction motor under operation. The system also isolates the motor from the supply if threshold values are exceeded by using sensor technology with PIC18f4550 microcontroller. The hardware system was tested with a single phase induction motor. The results obtained show that the measured values conform to analog meters readings. The system adequately monitors and isolates the induction motor to prevent it from breaking down.

Keywords: Induction motor, Microcontroller, Monitoring, Protection, Sensor

 TABLE OF CONTENTS

COVER PAGE

TITLE PAGE

APPROVAL PAGE

DEDICATION

ACKNOWELDGEMENT

ABSTRACT

CHAPTER ONE

INTRODUCTION

1.1      BACKGROUND OF THE PROJECT

• PROBLEM STATEMENT
• AIM/OBJECTIVE OF THE PROJECT
• SCOPE / LIMITATION OF THE PROJECT
• APPLICATION OF THE PROJECT
• SIGNIFICANCE OF THE PROJECT

CHAPTER TWO

LITERATURE REVIEW

• OVERVIEW OF INDUCTION MOTOR
• BASIC PARTS OF AN INDUCTION MOTOR
• TYPES OF INDUCTION MOTORS
• ADVANTAGES OF INDUCTION MOTOR
• REVIEW OF RELATED STUDIES

CHAPTER THREE

METHODOLOGY

• BLOCK DIAGRAM
• VOLTAGE MEASUREMENT AND MONITORING
• CURRENT MEASUREMENT AND MONITORING
• TEMPERATURE MEASUREMENT AND MONITORING
• MEASUREMENT AND CONTROL SYSTEM DEVELOPMENT
• MEASUREMENT AND CONTROL SYSTEM IMPLEMENTATION

CHAPTER FOUR

4.1      RESULT AND DISCUSSION

CHAPTER FIVE

• CONCLUSION
• RECOMMENDATION

REFERENCES

CHAPTER ONE

1.0                                                   INTRODUCTION

1.1                                      BACKGROUND OF THE STUDY

Induction motors are the most widely used electro-mechanical devices in a variety of applications and since the squirrel cage induction motor is low-priced, simple, robust, and rugged, it is considered worldwide as the workhorse in industrial applications (Chaturvedi, Akash, Mayank, and Sharif, 2014). Many researchers focused on condition monitoring of three induction motor components: the stator, rotor and bearings. Little attention has been paid to voltage unbalance in the motor supply and the development of induction motor parameters monitoring system (Mirabbasi, Ghodratollah, and Mehrdad, 2009).

Operation of induction motors at voltage and frequencies other than the nominal values, sudden increase in load or load thrown off can cause significant changes in the motor speed. Increase in speed leads to increase in operating temperature and decreases the functional horse power, which leads to reduced life of motor (Pari, Kavipriya, Naveenadevi, Preethi and Suryadharsini, 2017). Induction motor speed and temperature is more affected by high amplitudes of voltage fluctuations, whilst the torque and efficiency are more affected for middle and high amplitudes (Zhao, Ciufo and Perera, 2012).

A temperature protection system is needed to protect induction motor stator winding against thermal overloads in an application where induction motors are frequently started, overloaded and used in high inertia applications with long starting times (Aleksejs, 2015). Thermal overheating degrades the chemical stability of the materials used for stator winding insulation and accelerates the aging process. Unbalance voltage can occur due to Intermittent load or strong fluctuations in power demand, presence of larger single-phase consumers, (Zhao, Ciufo and Perera, 2012), presence of higher harmonics in the supply voltage (Miloje, 2012).

The present day requirement for ever increasing reliability of electrical machines is parameters monitoring and protection against variations. Though, it does not remedy the fault in most cases but early detection of variations in voltage, current and temperature and appropriate action would eliminate subsequent damage to motor, then reducing the cost of repair and downtime. The traditional measuring apparatus like meters cannot give a continuous measuring, monitoring and storing results of induction motor parameters (Shubhang and Rajesh, 2011).

Hence, a cost effective, reliable and accurate hardware system is designed to have a continuous monitoring of these parameters and protect against variation in voltage, current and temperature and isolate the induction motor from supply if the threshold value is exceeded.

1.2                                            PROBLEM STATEMENT

Induction motors are widely used in industrial, commercial and residential systems, because of their ruggedness, simplicity and relatively low cost. Approximately 65% of the electricity consumed in industry is used to drive electrical motors. Therefore, the efficiency and reliability of induction motors operation is of major importance, in order to improve the energy efficiency in industry (Quispe et al, 2011). Squirrel cage induction motors are the most important AC machines in industry. Low cost, high reliability, low inertia and high transient torque capacity are among the advantages of these motors. Many resources show that 35%–45% of motor failures are caused by stator insulation breakdown. For small induction machines, thermal overloading (which can cause high temperature), under or over voltage/current are causes of the induction motor stator winding insulation degradation process (Bonnett et al., 2012).

Thermal devices and models, which assume fixed thermal characteristics of the motor, are not capable of providing sufficient thermal protection since they have no means of giving a correct temperature estimate when the thermal characteristics change. Therefore, in order to extend the insulation life of the induction motor, it is critical to monitor the stator winding temperature, voltage, current and protect the motor under thermal overloading conditions such as motor stall, jam, overload, unbalanced operation, and situations where the cooling ability of the motor is accidentally reduced (Farag et al., 2014).

1.3                               AIM AND OBJECTIVES OF THE STUDY

The main aim of this work is to build a system that will analyze and alarm an abnormality of the motor and prevent the damage in case of unbalance voltage or current and high temperature. The objectives of the study are:

1. To protect induction motor from breaking down
2. To build a protection and monitoring system for industrial induction motor
3. To ensure safety of an induction motor.
4. To improve the efficiency of the induction motor.

1.4                              SCOPE / LIMITATION OF THE PROJECT

This work is on protection and monitoring system for industrial induction motor. This scheme can alert the operation of the motor in order to prevent damage and to extend the life time reducing maintenance costs. It consists of several sensor devices and coordinator device. The coordinator device reads sensor measured data which located in induction motor and transmits them to the LCD, mikroC source code for PIC libraries is the software used for data acquisition, conversion, communication and display.

Faults result in loses in the motor and also leads to increased electricity charges due to poor power factor, reduced efficiency, and power consumed. This paper is limited to motors operating directly on sinusoidal power and not through adjustable speed drives.

1.5                                          APPLICATION OF THE PROJECT

This device can be used in the following places:

1. workshops
2. industries
3. electronics hobbyist, etc. for protecting, and monitoring of an AC motor

1.6                                                      SIGNIFICANCE OF THE STUDY

This research work will throw more light on the best techniques for controlling and monitoring an induction motor. This study will also be designed to be of immense benefit to all the users of electric motor most especially in industries.

It will also serve as a guide to whoever that wants to purchase an induction motor.

Finally, it will also serve as a useful piece of information for both producers and users of electric motor.