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Design And Construction Of Automatic Change-over For Three Phases
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3.3 CIRCUIT BREAKER
This is defined as electro-mechanical device design to make and break the electric circuit under normal and abnormal conductor such as those of short circuit, the circuit being broken automatically. The majority of circuit breaker is either oil or air blast types.
Regulation 433-2 require the characteristic of the device (fuse or circuit breaker) protecting the circuit to be coordinated with the conductor forming the circuit such that.
(i) Its normal current (fuse rating) or current setting for circuit breaker (IN) is not less than this design current which is the minimum or normal circuit current (IB).
(ii) The current which operate the fuse or circuit breaker, causing it to disconnect the circuit (RZ). does next exceed 1.45times the lowest of any current carrying capacities (IZ) for the circuit conductor, using formula: IB<IN<IZ and IZ<1.45IZ.
(iii) It is not greater than the current-carrying (IZ)of the circuit conductor.
3.4 RESET TIMER
A relay designed to operate after a calculated time delay is called a “timer relay†or timer. If the timer delay is fixed regardless of the input of the relay (in excess of pick-up value) the relay is termed “definite timerâ€. The amount of time delay may less for greater input to the relay, such relay are called “inverse†very inverse or “extremely inverse†depending on the extent which relay is reduced for an increase in the input to the relay.
A relay designed to have no intentional time is said to be instantaneous.
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ABSRACT - [ Total Page(s): 1 ]ABSTRACT The main aim of any electric power supply in the world is to provide uninterrupted power supply at all times to all its consumers. Although in developing countries, the electric power generated to meet the demands of the growing consumers of electricity is insufficient hence instability and outage. Power instability or outage in general does not promote development in the public and private sector. The inventors do not feel secure to come into a country with constant or freq ... Continue reading---
APPENDIX A - [ Total Page(s): 1 ]BILL OF ENGENEERING MEARSUREMENT AND EVALUTION (BEME)The table below shows the cost estimate in naira and kobo of constructed automatic change-over panel.Bill of Engineering Measurement and Evaluation ... Continue reading---
TABLE OF CONTENTS - [ Total Page(s): 1 ]TABLE OF CONTENTS Title Page Certification Acknowledgements Abstract Table of Contents CHAPTER ONE1.1 Introduction 1.2 Aim and Objective of the Project 1.3 Scope of the Project CHAPTER TWO2.1 Literature Review 2.2 Manual Change-over Switch 2.3 Automatic Change-over Switch 2.4 Related Work 2.5 Reasons for Automatic Change-over Switch 2.6 Problems of Automatic Change-over Switch CHAPTER THREE3.1 Methodolog ... Continue reading---
CHAPTER ONE - [ Total Page(s): 1 ]CHAPTER ONE1.1 INTRODUCTION Power instability in developing countries creates a need for automation of electrical power generation or alternative sources of power to back-up the utility supply. This automation is requiring as the rate of power outages become predominantly high. Research in the field of electrical electronics engineering has led to the tremendous discovers and inventions especially in the area of automation and power control. These invention have been useful in solvi ... Continue reading---
CHAPTER TWO - [ Total Page(s): 4 ]The circuit diagram of the flip flop and switching transistor stage of the related art.Another related art was the development of a single phase automatic change-over switch. This also related to the present invention i.e. it switches electrical power supply from public supply to generator in the event of a power outage or insufficient voltage but it is apply to single phase system while the present invention is apply to three (3) phase system, moreover, the system uses an electronic control cir ... Continue reading---
CHAPTER FOUR - [ Total Page(s): 4 ]CHAPTER FOURCONSTRUCTION4.1 LIST OF COMPONENT USEDThe following electronic components used in the project are list below(1) Voltmeter (2) Casing (3) Vero-Board(4) Transformers DC 12V(5) Diodes (6) Capacitors 100(7) Resistors 4k(8) Contactors (9) 16mm2 Cables(10) 1ooAmp connector (11) Bolt and Nuts(12) Indictor light (13) Relay three phase (14) 555IC timer 4.2 VERO BOARD: is a brand of strip-board, a p ... Continue reading---
CHAPTER FIVE - [ Total Page(s): 1 ]CHAPTER FIVE5.1 CONCLUSION The automatic change-over switch has immense advantage in every area where power is required it is a fact that there is hardly any aspect of human life were electrical power is not required, at home, offices, hospital, etc. It find a wide application scope, wherever the re-ability of electrical supply is necessary, for switching to an alternative source from main.5.2 RECOMMENDATIONThe automatic change-over switch is needed in every home and of ... Continue reading---
REFRENCES - [ Total Page(s): 1 ]REFERENCEB.L. and A.K. Theraja (1997): Electrical Technology, S. chand company LTDEngr. A.O Aduloju (2003): Electrical Power System, Evidence Nigeria VentureEngr. M.B Jenyo (2007): Electrical Power System III & IV lecture Notes, UnpublishedEngr. T.A. Mustapha (2006): Electrical Power System I & II inn lecture Notes, unpublishedInternet Research: http://www.electricalsolution.comM.S. Ahmed, A.S. Mohammed & C.B. Augusibo (2006): Development of a single Automatic change-over switch Federal Universi ... Continue reading---
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ABSRACT - [ Total Page(s): 1 ]ABSTRACT The main aim of any electric power supply in the world is to provide uninterrupted power supply at all times to all its consumers. Although in developing countries, the electric power generated to meet the demands of the growing consumers of electricity is insufficient hence instability and outage. Power instability or outage in general does not promote development in the public and private sector. The inventors do not feel secure to come into a country with constant or freq ... Continue reading---