Save this PDF as:

Size: px
Start display at page:

## Transcription

1 DC MOTORS DC Motors DC Motor is a Machine which converts Electrical energy into Mechanical energy. Dc motors are used in steel plants, paper mills, textile mills, cranes, printing presses, Electrical locomotives etc. Working principle It works on principle that When a current carrying conductor is placed in magnetic field, it experiences a force and the direction of the force is given by Fleming s left hand rule. Fleming s left hand rule states that Stretch out the first finger, second finger and thumb of your left hand so that they are at right angles to one another. The first finger points the direction of magnetic field from N-pole to S-pole, second finger points the direction of current and thumb will indicates the direction rotation of conductor Consider a conductor is placed in magnetic field. When a DC supply is connected to conductor, current flows through it which sets up its own flux around the conductor as shown in fig.(1). Let, the flux from N-pole to S-pole is main flux and the flux around the conductor is flux due to current carrying conductor. Now the interaction of both main flux and flux due to current carrying conductor, a force may act on conductor and conductor moves in anti-clock wise direction as shown in fig. (2). Back EMF & its Significance When a current carrying conductor (Armature winding) is placed in a magnetic field, torque develops and conductor (Armature) rotates the armature conductors cutting the magnetic field and an emf will be induced across the armature conductors. The direction of induced emf is opposite to the applied voltage. That is why this

2 ΦZN P induced emf is called back emf (E b) and the magnitude of the back emf is (E b) = * 60 A The equivalent circuit of dc motor is as shown in fig. (3). From the diagram the Vt - Eb armature current (I a) =. The main significance of the back emf is when the back emf is Ra zero, the armature current may be 4to 5 times the normal current. When the back emf is increases, the armature current is limited to its normal current i.e the back emf acts as safety valve. Types of D.C. Motors DC Motors are generally classified into three groups according to their field excitation. Those are (i) (ii) (iii) d.c. Shunt Motor d.c. Series Motor d.c Compound Motor DC Shunt Motor In a DC Shunt Motor, the field winding is connected in parallel with the armature winding as shown in fig (5). The shunt field winding has many turns of thin wire having high resistance. Therefore, a part of armature current flows through shunt field winding and the remaining current flows through the load. From the diagram, Shunt field current I sh = V t / R sh Armature current I L = I a + I sh (or) I a = I L - I sh Terminal voltage V t = E b + I a R a + B. D Generated EMF E b = V t - I a R a - B. D Power developed in armature = Eg Ia Power delivered to load = V t I L = V t (I a I sh) Where I a = Armature current, R a = Armature Resistance, V t = Terminal voltage, I L = Load current and B.D = Brush contact drop DC Series Motor If the field winding is connected in series with armature winding as shown in fig.(6) is called DC Series Motor. The series field winding has a few turns of thick having low resistance. From the circuit, Armature current = Series field current = Load current i.e I a = I se = I L Terminal voltage, V t = E b + I a R a + I se R se + B. D

3 = E b + I a (R a + R se) + B. D Generated EMF E b = V t - I a (R a + R se) - B. D Power developed in armature = Eb Ia In put Power = V t I L = V t I a (since I a = I L) Where I a = Armature current, R a = Armature Resistance, V t = Terminal voltage, I L = Load current and B.D = Brush contact drop DC Compound Motor In a DC compound motor, there are two sets of field windings on each pole, one is in series with the armature and the other in parallel with the armature. Based on these field winding connections, the DC compound moors are classified into (i) Long shunt compound motor (ii) Short shunt compound motor Long shunt compound motor In a Long Shunt Compound motor, the shunt field winding is in parallel with both series field and armature winding as shown in fig. (7). From the diagram Shunt field current Ish = Vt / Rsh Armature current I L = I a + I sh (or) I a or I se = I L - I sh Terminal voltage V t = E b + I a R a + I se R se) + B. D Generated EMF E g = V t - I a R a - I se R se - B. D = V t - I a (R a + R se) - B. D Power developed in armature = Eb Ia Input Power = V t I L = V t (I a + I sh) Where I a = Armature current, R a = Armature Resistance, V t = Terminal voltage, I L = Load current and B.D = Brush contact drop Short shunt compound motor In a Short Shunt Compound motor, the shunt field winding is connected in parallel with armature winding only as shown in fig. (8). From the diagram

4 Series field current I se = I L = I a + I sh Armature current I a = I se - I sh Terminal voltage V t = E b + I a R a + I se R se + B. D Generated EMF E b = V t - I a R a - I se R se - B. D Power developed in armature = E b I a Input Power = V t I L Where current I a = Armature current, R a = Armature Resistance, V t = Terminal voltage, I L = Load and B.D = Brush contact drop Armature Torque (Ta) Equation of D.C. Motor Torque is defined as turning and twisting movement of force about an axis. Mathematically, Torque can be defined as product of force and the radius at which the force is act i. T = F*r. Let a pulley with a radius of r is rotating with a speed of N rpm, a force of F newtons is acting on the pulley. Then Work done by the force = Force * Distance = F * 2 π r joules Power developed = Work done * time [time = time required to complete a revolution = N/60] = F * 2 π r * N/60 = (F * r ) 2 π N/60 = T 2 π N/60 watts If the torque developed by the motor is T a, The Power developed in armature (P a ) = T a 2 π N/60 watts (1) But Power developed in armature (P a ) = E b I a (2) From equations (1) & (2), T a 2 π N/60 = E b I a Eb Ia T a = 2ΠN / 60 1 P T a = *ZIa 2Π A P Armature torque T a = 0.159ZIa A Shaft Torque (T sh) A part of armature torque is lost as Iron & Mechanical losses, the remaining torque is available at shaft of the motor, this torque is called shaft torque (T sh). Practically, shaft torque (T sh) is less than armature torque (T a).

5 Output Power Shaft torque (T sh) = 9.55 N Losses & Effiency of a D.C. Machine Losses of a D.C. Machine The losses in a d.c. machine (generator or motor) may be divided into three classes. Those are (i) copper losses (ii) iron or core losses and (iii) mechanical losses. Copper losses The copper losses are directly proportional to square of the current passing through the winding. Copper losses due to currents in the various windings of the machine are: (i) Armature copper loss = I a 2 R a ; Where I a is the armature current and R a armature resistance. (ii) Shunt field copper loss = I 2 sh R sh ; Where I sh is the shunt field current and R sh shunt field resistance. (iii) Series field copper loss = I 2 se R se ; Where I se is the series field current & R se series field resistance. Iron or Core losses These losses occur in the armature of a d.c. machine and are due to the rotation of armature in the magnetic field of the poles. They are of two types (i) Hysteresis loss (ii) Eddy current loss. Hysteresis loss The Hysteresis loss, P h α η B 1.6 m f V watts Where B m = Maximum flux density in armature, f = Frequency, V = Volume of armature in m 3 η = Steinmetz hysteresis co-efficient In order to reduce this loss in a d.c. machine, armature core is made of silicon steel material, because the silicon steel material has a low value of Steinmetz hysteresis co-efficient. Eddy current loss: The Eddy current loss, P e α K e B 2 m f 2 t 2 V watts Where Ke = Constant, Bm = Maximum flux density in Wb/m 2, f = Frequency t = Thickness of lamination in mts and V = Volume of core in m 3 Eddy current losses can be reduced by laminating the armature core and pole core. Mechanical losses These losses are due to friction and windage effects. Mechanical losses are classified into two classes, those are (i) Friction loss (These losses are due to friction at bearings and brushes)

6 (ii) Windage loss (These losses are due air friction of rotating armature). These losses depend upon the speed of the machine. But for a given speed, they are practically constant. Since the iron and mechanical losses are independent of load, these losses are called as constant losses. But the copper loss depends on load or load current, so the copper losses are called as variable losses. The constant losses and Shunt field copper losses are combinely called as stray losses. Therefore the total losses are the sum of constant losses and variable losses. Effiency of a D.C. Machine The power stage diagram of a DC Machine is as shown in figure(9). for DC Generator The efficiency of a d.c. generator is not constant but varies with load. Consider a shunt generator delivering a load current I L at a terminal voltage V t. Generator output = V t I L Generator input = Output + Losses = V t I L + Variable losses + Constant losses = V t I L + I 2 a R a + P i = V t I L + (I L + I sh) 2 R a + P i (I a = I L + I sh) Output power VtIL Generator Effiency (η gen) = *100 = * Input power VtIL + (IL + Ish) Ra + Pi For DC Motor The efficiency of a d.c. motor is not constant but varies with load. Consider a shunt motor delivering a load current I L at a terminal voltage V t. Motor Input = V t I L Motor Output = Input - Losses = V t I L - Variable losses - Constant losses = V t I L - I 2 a R a - P i = V t I L - (I L - I sh) 2 R a - P i (I a = I L - I sh) Output power VtIL Motor Effiency (η motor) = *100 = * Input power Vt IL - (IL - Ish) Ra - Pi

7 D.C. Motor Characteristics The performance of a d.c. motor can be measured from its characteristic curves known as motor Characteristics, below mentioned are the three important characteristics of a d.c. motor: (i) Torque and Armature current characteristic (Ta/Ia) It is the curve between armature torque Ta and armature current Ia of a d.c. motor. It is also known as electrical characteristic of the motor. (ii) (iii) Speed and armature current characteristic (N/Ia) It is the curve between speed N and armature current Ia of a d.c. motor. It is very important characteristic in the selection of the motor for a particular application. Speed and torque characteristic (N/Ta) It is the curve between speed N and armature torque Ta of a d.c. motor. It is also known as mechanical characteristic. Characteristics of Shunt Motor The connections of a d.c. shunt motor is shown in fig.(9). The field current I sh is constant since the field winding is directly connected to the constant supply voltage V t. Hence, the flux in a shunt motor is constant (Φ sh). (i) Ta/Ia Characteristic: We know that in a d.c. motor, Ta /Ia. Since the motor is operating from a Φ constant supply voltage, flux is constant. Ta Ia Hence Ta/Ia characteristic is a straight line passing through the origin as shown in Fig. (10). It is clear from the curve that a very large current is required to start a heavy load. Therefore, a shunt motor should not be started on heavy load.

8 (iii) N/Ia Characteristic The speed N of a. d.c. motor is given by N α Eb. The flux (Φ) in a shunt motor is almost constant under normal conditions. Therefore, the speed of a shunt motor will remain constant as the armature current varies. But practically, when load is increased, load current I L and armature current I a also increased (since I a = I L+ I sh). Therefore the back emf E b =(Vt- Ia Ra) decrease due to the armature resistance drop and results in slightly decrease in the speed of the motor. (iv) N/Ta Characteristic The curve is obtained by plotting the values of N and T a for various armature currents. It may be seen that speed falls as the load torque increases as shown in N/Ta characteristics. Characteristics of Series Motor The connections of a d.c. series motor is shown in fig.(11). From the circuit I L = I se = I a. If the load on the motor increases, then the armature current also increases. Hence, the flux in a series motor increases with the increase in armature current (Φ I f ) and vice-versa. (i) Ta/Ia Characteristic: We know that: T a I a Before saturation, Φ I a so that T a I 2 a and after magnetic saturation, Φ is constant so that T a Φ I a. Therefore up to saturation, Torque Vs Armature current curve is a parabola and

9 after saturation, torque is directly proportional to the armature current. Therefore, Ta/Ia curve after saturation is a straight line as shown in fig.(12). (ii) N/Ia Characteristic: The speed N of a. d.c. motor is given by N α but the flux (Φ) field current (I se = I a). Therefore the speed Eb. For constant back emf, speed N α (N) Vs armature current (Ia) curve is hyperbolic as shown in Fig. (13). 1 Ia N α 1. Thus, the Speed (iii) N/Ta Characteristic: The speed (N) Vs Torque (Ta) characteristic of a series motor is shown in Fig. (14). Speed Control of D.C. Shunt Motor There are two methods to control the speed of a d.c. motor, namely: (i) Armature Control Method (ii) Flux Control Method Armature Control Method Eb We know that the speed of a d.c. motor is N α Vt - Ia Ra or N = K From the above equation it is clear that, by varying the back emf (E b) the speed of the motor can be varied. The following figure shows the arrangement for armature control method. In this method an additional resistance of R ohms is connected in series with the armature.

10 Now the speed of the motor N E b i.e N V t I a (R a + R). Due to the voltage drop in resistance (R), the back e.m.f. (E b) is decreased. Since N E b, the speed of the motor is reduced from the normal speed. This method gives the speeds always less than the normal speeds. The main drawbacks of this method are (i) A large amount of power is wasted in the resistance (R) since it carries full armature current Ia. (ii) The output and efficiency of the motor are reduced due to large amount of power is wasted in the resistance (R). (iii) This method results in poor speed regulation. Flux or Field Control Method Eb We know that the speed of a d.c. motor is N α From the above equation it is clear that, by varying the flux (Φ), the speed of the motor can be varied hence it is called flux or field control method. The following figure shows the arrangement for flux control method. In this method an additional resistance of R ohms is connected in series with the shunt field winding. By increasing the additional resistance, the flux (Φ) decreases, this results in increase in speed from the normal speed. This method always gives the speeds above the normal speed. Advantages (i) This is an easy and convenient method. (ii) It is an inexpensive method since very little power is wasted in additional resistance (R) due to shunt field current I sh. The main drawback of this method is only speeds higher than the normal speed can be obtained since the total field circuit resistance cannot be reduced below the shunt field resistance (R sh).

### Direct Current Motors

Direct Current Motors Introduction and Working Principle A dc motor is used to converts the dc electrical power into mechanical power. These motors are used in Airplanes, Computers, robots, toys and mining

### D.C. Generators. Chapter (1) Introduction. 1.1 Generator Principle. 1.2 Simple Loop Generator

Chapter (1) D.C. Generators Introduction Although a far greater percentage of the electrical machines in service are a.c. machines, the d.c. machines are of considerable industrial importance. The principal

### SPEED CONTROL OF DC SHUNT MOTOR

INDEX NO. : M-140 TECHNICAL MANUAL FOR SPEED CONTROL OF DC SHUNT MOTOR Manufactured by : PREMIER TRADING CORPORATION (An ISO 9001:2000 Certified Company) 212/1, Mansarover Civil Lines, MEERUT. Phone :

### Induction type Energy meter Construction

Induction type Energy meter Construction The four main parts of an energy meter are: Driving system Moving system Braking system and Registering system The construction is as shown below: Fig. Construction

### ELEN 236 DC Motors 1 DC Motors

ELEN 236 DC Motors 1 DC Motors Pictures source: http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/mothow.html#c1 1 2 3 Some DC Motor Terms: 1. rotor: The movable part of the DC motor 2. armature: The

### 2 Principles of d.c. machines

2 Principles of d.c. machines D.C. machines are the electro mechanical energy converters which work from a d.c. source and generate mechanical power or convert mechanical power into a d.c. power. These

### MAGNETIC EFFECTS OF ELECTRIC CURRENT

MAGNETIC EFFECTS OF ELECTRIC CURRENT It is observed that when a compass is brought near a current carrying conductor the needle of compass gets deflected because of flow of electricity. This shows that

### Almost 200 years ago, Faraday looked for evidence that a magnetic field would induce an electric current with this apparatus:

Chapter 21 Electromagnetic Induction and Faraday s Law Chapter 21 Induced EMF Faraday s Law of Induction; Lenz s Law EMF Induced in a Moving Conductor Changing Magnetic Flux Produces an E Field Inductance

### 2006 MINI Cooper S GENINFO Starting - Overview - MINI

MINI STARTING SYSTEM * PLEASE READ THIS FIRST * 2002-07 GENINFO Starting - Overview - MINI For information on starter removal and installation, see the following articles. For Cooper, see STARTER WITH

### Module 9. DC Machines. Version 2 EE IIT, Kharagpur

Module 9 DC Machines Lesson 38 D.C Generators Contents 38 D.C Generators (Lesson-38) 4 38.1 Goals of the lesson.. 4 38.2 Generator types & characteristics.... 4 38.2.1 Characteristics of a separately excited

### Danyal Education (Contact: ) A commitment to teach and nurture. c) sketch a graph of voltage output against time for a simple a.c.

(Contact: 9855 9224) Electricity and Magnetism: Electromagnetic Induction (*) (#) Candidates should be able to: a) deduce from Faraday s experiments on electromagnetic induction or other appropriate experiments:

EE6401 ELECTRICAL MACHINES I UNIT I: MAGNETIC CIRCUITS AND MAGNETIC MATERIALS PART: A 1. Define EMF and MMF. 2. Name the main magnetic quantities with their symbols having the following units: Webers,

### Electrical Machines-I (EE-241) For S.E (EE)

PRACTICAL WORK BOOK For Academic Session 2013 Electrical Machines-I (EE-241) For S.E (EE) Name: Roll Number: Class: Batch: Department : Semester/Term: NED University of Engineer ing & Technology Electrical

### EE6401 ELECTRICAL MACHINES I UNIT I: MAGNETIC CIRCUITS AND MAGNETIC MATERIALS PART: A 1. Define EMF and MMF. 2. Name the main magnetic quantities

EE6401 ELECTRICAL MACHINES I UNIT I: MAGNETIC CIRCUITS AND MAGNETIC MATERIALS PART: A 1. Define EMF and MMF. 2. Name the main magnetic quantities with their symbols having the following units: Webers,

### VIII. Three-phase Induction Machines (Asynchronous Machines) Induction Machines

VIII. Three-phase Induction Machines (Asynchronous Machines) Induction Machines 1 Introduction Three-phase induction motors are the most common and frequently encountered machines in industry simple design,

### INTRODUCTION Principle

DC Generators INTRODUCTION A generator is a machine that converts mechanical energy into electrical energy by using the principle of magnetic induction. Principle Whenever a conductor is moved within a

### TESTING OF D.C. MACHINES

CONTENTS C H A P T E R 31 Learning Objectives Brake Test Swinburne s Test Advantages of Swinburne s Test Main Disadvantages Regenerative or Hopkinson s Test Alternative Connections for Hopkinson s Test

### The Wound-Rotor Induction Motor Part I

Experiment 1 The Wound-Rotor Induction Motor Part I OBJECTIVE To examine the construction of the three-phase wound-rotor induction motor. To understand exciting current, synchronous speed and slip in a

### ELECTROMAGNETISM. 1. the number of turns. 2. An increase in current. Unlike an ordinary magnet, electromagnets can be switched on and off.

ELECTROMAGNETISM Unlike an ordinary magnet, electromagnets can be switched on and off. A simple electromagnet consists of: - a core (usually iron) - several turns of insulated copper wire When current

### Basic Instruments Introduction Classification of instruments Operating principles Essential features of measuring

Basic Instruments www.worldwebsites8.blogspot.com Introduction Classification of instruments Operating principles Essential features of measuring instruments PMMC Instruments Moving Iron instruments Introduction

### Lecture 20: Stator Control - Stator Voltage and Frequency Control

Lecture 20: Stator Control - Stator Voltage and Frequency Control Speed Control from Stator Side 1. V / f control or frequency control - Whenever three phase supply is given to three phase induction motor

### Electrical machines - generators and motors

Electrical machines - generators and motors We have seen that when a conductor is moved in a magnetic field or when a magnet is moved near a conductor, a current flows in the conductor. The amount of current

### Chapter 22: Electric motors and electromagnetic induction

Chapter 22: Electric motors and electromagnetic induction The motor effect movement from electricity When a current is passed through a wire placed in a magnetic field a force is produced which acts on

### The Effect of DC Machine Adjustment on Loop Unbalance

The Effect of DC Machine Adjustment on Loop Unbalance WMEA, Edmonton, Alberta, Canada June 11-13, 13, 2008 Rich Hall Morgan AM&T Jim Shackelford Peabody Energy Technical Contributor Jason Conrad GE Canada

### ECEg439:-Electrical Machine II

ECEg439:-Electrical Machine II 2.2 Main Structural Elements of DC Machine Construction of DC Machines A DC machine consists of two main parts 1. Stationary Part (Stator):-It is designed mainly for producing

### 10. Starting Method for Induction Motors

10. Starting Method for Induction Motors A 3-phase induction motor is theoretically self starting. The stator of an induction motor consists of 3-phase windings, which when connected to a 3-phase supply

### Unit-I MEASURING INSTRUMENTS

Unit-I MEASURING INSTRUMENTS 1.1 Definition of instruments: An instrument is a device in which we can determine the magnitude or value of the quantity to be measured. The measuring quantity can be voltage,

### To study the constructional features of ammeter, voltmeter, wattmeter and energymeter.

Experiment o. 1 AME OF THE EXPERIMET To study the constructional features of ammeter, voltmeter, wattmeter and energymeter. OBJECTIVE 1. To be conversant with the constructional detail and working of common

### Chapter 7: DC Motors and Transmissions. 7.1: Basic Definitions and Concepts

Chapter 7: DC Motors and Transmissions Electric motors are one of the most common types of actuators found in robotics. Using them effectively will allow your robot to take action based on the direction

### Journal of Asian Scientific Research. DESIGN OF SWITCHED RELUCTANCE MOTOR FOR ELEVATOR APPLICATION T. Dinesh Kumar. A. Nagarajan

Journal of Asian Scientific Research journal homepage: http://aessweb.com/journal-detail.php?id=5003 DESIGN OF SWITCHED RELUCTANCE MOTOR FOR ELEVATOR APPLICATION T. Dinesh Kumar PG scholar, Department

### MAGNETIC EFFECT OF ELECTRIC CURRENT

BAL BHARATI PUBLIC SCHOOL, PITAMPURA Class X MAGNETIC EFFECT OF ELECTRIC CURRENT 1. Magnetic Field due to a Current through a Straight Conductor (a) Nature of magnetic field: The magnetic field lines due

### Synchronous Generators I. Spring 2013

Synchronous Generators I Spring 2013 Construction of synchronous machines In a synchronous generator, a DC current is applied to the rotor winding producing a rotor magnetic field. The rotor is then turned

### Chapter 3.2: Electric Motors

Part I: Objective type questions and answers Chapter 3.2: Electric Motors 1. The synchronous speed of a motor with 6 poles and operating at 50 Hz frequency is. a) 1500 b) 1000 c) 3000 d) 750 2. The efficiency

### Permanent Magnet DC Motor

Renewable Energy Permanent Magnet DC Motor Courseware Sample 86357-F0 A RENEWABLE ENERGY PERMANENT MAGNET DC MOTOR Courseware Sample by the staff of Lab-Volt Ltd. Copyright 2011 Lab-Volt Ltd. All rights

### Permanent Magnet DC Motor Operating as a Generator

Exercise 2 Permanent Magnet DC Motor Operating as a Generator EXERCIE OBJECTIVE When you have completed this exercise, you will be familiar with the construction of permanent magnet dc motors as well as

### Synchronous Generators I. EE 340 Spring 2011

Synchronous Generators I EE 340 Spring 2011 Construction of synchronous machines In a synchronous generator, a DC current is applied to the rotor winding producing a rotor magnetic field. The rotor is

### Experiment 5 Shunt DC Motor (I)

Objective To determine the torque-speed and efficiency characteristic curves. To f out how to reverse the direction of rotation of a shunt dc motor. Introduction shunt dc motor is essentially the same

### Armature Reaction and Saturation Effect

Exercise 3-1 Armature Reaction and Saturation Effect EXERCISE OBJECTIVE When you have completed this exercise, you will be able to demonstrate some of the effects of armature reaction and saturation in

### Motors. Book pg Syllabus /09/2016. The Butterfly Effect. cgrahamphysics.com 2015

Motors Book pg 187 189 Syllabus 6.11 6.14 05/09/2016 The Butterfly Effect The Motor effect where? What device does not use a motor? Aim Know the link between movement, magnetism and current Know how electric

### MAGNETIC EFFECTS OF CURRENT

Magnet A magnet is an object, which attracts pieces of iron, steel, nickel and cobalt. Naturally Occurring Magnet Lodestone is a naturally occurring magnet. It is actually a black coloured, oxide ore of

### Fachpraktikum Elektrische Maschinen. Theory of Induction Machines

Fachpraktikum Elektrische Maschinen Theory of Induction Machines Prepared by Arda Tüysüz January 2013 Fundamentals Induction machines (also known as asynchronous machines) are by far the most common type

### Figure 1: Relative Directions as Defined for Faraday s Law

Faraday s Law INTRODUCTION This experiment examines Faraday s law of electromagnetic induction. The phenomenon involves induced voltages and currents due to changing magnetic fields. (Do not confuse this

### Twenty Ways to Optimize Energy Efficiency in the Use of Induction Motors

Twenty Ways to Optimize Energy Efficiency in the Use of Induction Motors Course No: M06-021 Credit: 6 PDH A. Bhatia Continuing Education and Development, Inc. 9 Greyridge Farm Court Stony Point, NY 10980

### Physics 121 Practice Problem Solutions 11 Faraday s Law of Induction

Physics 121 Practice Problem Solutions 11 Faraday s Law of Induction Contents: 121P11-1P, 3P,4P, 5P, 7P, 17P, 19P, 24P, 27P, 28P, 31P Overview Magnetic Flux Motional EMF Two Magnetic Induction Experiments

### Unit III A.C. Machines Explain the construction of induction motor. General principle Construction Stator:

Unit III A.C. Machines - Principle of operation of 3-phase Induction Motor Torque, slips characteristics- Speed control methods Single-phase Induction motor starting methods Principle of operation of Alternators.

### Electric Motors and Drives

EML 2322L MAE Design and Manufacturing Laboratory Electric Motors and Drives To calculate the peak power and torque produced by an electric motor, you will need to know the following: Motor supply voltage:

### Shape - Typical designs with sector angles of pi/2 [90 degrees], and 2pi/3 [120 degrees] are shown below.

Sector Torus Cores Started 01 Jun 012 By Newton E. Ball Definitions - Torus - Restricted to Circular Torus, the solid shape formed by the rotation of a circular area, about an axis that is external to

### CHAPTER 7 INDUCTION MOTOR

CHAPTE 7 INDUCTION MOTO Summary: 1. Induction Motor Construction. Basic Induction Motor Concepts - The Development of Induced Torque in an Induction Motor. - The Concept of otor Slip. - The Electrical

### Application Information

Moog Components Group manufactures a comprehensive line of brush-type and brushless motors, as well as brushless controllers. The purpose of this document is to provide a guide for the selection and application

### D.C. CONTENTS CONTENTS. Learning Objectives. Generator converts mechanical energy into electrical energy using electromagnetic induction

CONTENTS C H A P T E R26 Learning Objectives es Generator Principal Simple Loop Generator Practical Generator Yoke Pole Cores and Pole Shoes Pole Coils Armature Core Armature Windings Bushes and Bearings

### 15 Electrical Circuits Name Worksheet A: SERIES CIRCUIT PROBLEMS

Worksheet A: SERIES CIRCUIT PROBLEMS be careful to use proper significant figures on all answers 1. What would be the required voltage of an energy source in a circuit with a current of 10.0 A and a resistance

Purpose Theory Faraday's Law of Induction a. To investigate the emf induced in a coil that is swinging through a magnetic field; b. To investigate the energy conversion from mechanical energy to electrical

### 9.9 Light Chopper Drive Motor

9.9 Light Chopper Drive Motor This application is for a motor to drive a slotted wheel which in turn interrupts (chops) a light beam at a frequency of 200 H z. The chopper wheel has only a single slot

### MAGNETIC EFFECTS OF ELECTRIC CURRENT. To understand Magnetic effects of Electric current, first we should know what is the Magnet?

MAGNETIC EFFECTS OF ELECTRIC CURRENT To understand Magnetic effects of Electric current, first we should know what is the Magnet? Magnet A Magnet is an object which attracts pieces of iron, steel, nickel

### SYLLABUS 1. SYNCHRONOUS GENERATOR 9 2. SYNCHRONOUS MOTOR 8

SYLLABUS 1. SYNCHRONOUS GENERATOR 9 Constructional details Types of rotors emf equation Synchronous reactance Armature reaction Voltage regulation EMF, MMF, ZPF and A.S.A methods Synchronizing and parallel

### INDUCED ELECTROMOTIVE FORCE (1)

INDUCED ELECTROMOTIVE FORCE (1) Michael Faraday showed in the 19 th Century that a magnetic field can produce an electric field To show this, two circuits are involved, the first of which is called the

### BU Motors and Generators training. Start here menu. BU Motors and Generators April 18, 2011 Slide 1

BU Motors and Generators training Start here menu April 18, 2011 Slide 1 1 Dear Student, Welcome to Technical introduction to motors and generators e-learning course program! K115e K110e K116e K111e K117e

### Motor Basics AGSM 325 Motors vs Engines

Motor Basics AGSM 325 Motors vs Engines Motors convert electrical energy to mechanical energy. Engines convert chemical energy to mechanical energy. 1 Motors Advantages Low Initial Cost - \$/Hp Simple &

### ELECTRICAL MACHINES-II LABORATORY MANUAL

ELECTRICAL MACHINES-II LABORATORY MANUAL T. ANIL KUMAR Associate Professor Department of Electrical and Electrical Engineering N. SINDHU Assistant Professor Department of Electrical and Electrical Engineering

### Speed Control of D.C. MOTOR Using Chopper

Speed Control of D.C. MOTOR Using Chopper 1 VARUN ROHIT VADAPALLI, 2 HEMANTH KUMAR KELLA, 3 T.RAVI SEKHAR, 4 Y.DAVID SAMSON, 5 N.AVINASH 1,2,3,4 UG Student, 5 Assistant Professor, Department of Electrical

### Chapter 3.1: Electrical System

Part-I: Objective type Questions and Answers Chapter 3.1: Electrical System 1. The heat input required for generating one kilo watt-hour of electrical output is called as. a) Efficiency b) Heat Rate c)

### Chapter 2 PRINCIPLES OF AFPM MACHINES. 2.1 Magnetic circuits Single-sided machines Double-sided machines with internal PM disc rotor

Chapter 2 PRINCIPLES OF AFPM MACHINES In this chapter the basic principles of the AFPM machine are explained in details. Considerable attention is given to the magnetic circuits, windings, torque production,

### 2. ELECTRIC MOTORS. 2.1 Introduction. 2.2 Motor Types

2. ELECTRIC MOTORS Syllabus Electric motors: Types, Losses in induction motors, Motor efficiency, Factors affecting motor performance, Rewinding and motor replacement issues, Energy saving opportunities

### Unit 32 Three-Phase Alternators

Unit 32 Three-Phase Alternators Objectives: Discuss the operation of a three-phase alternator. Explain the effect of rotation speed on frequency. Explain the effect of field excitation on output voltage.

### SERVICE SHOP NOTES. Use ohmmeter to check the resistance between the leads.

SERVICE SHOP NOTES LIMA MAC SELF VOLTAGE REGULATED GENERATORS Troubleshooting Tips Symptom: Engine bogs down or stalls even at no load. Problem: Main stator has one or more taps wound or connected incorrectly.

### Phys102 Lecture 20/21 Electromagnetic Induction and Faraday s Law

Phys102 Lecture 20/21 Electromagnetic Induction and Faraday s Law Key Points Induced EMF Faraday s Law of Induction; Lenz s Law References SFU Ed: 29-1,2,3,4,5,6. 6 th Ed: 21-1,2,3,4,5,6,7. Induced EMF

### DESIGN OF AXIAL FLUX BRUSHLESS DC MOTOR BASED ON 3D FINITE ELEMENT METHOD FOR UNMANNED ELECTRIC VEHICLE APPLICATIONS

DESIGN OF AXIAL FLUX BRUSHLESS DC MOTOR BASED ON 3D FINITE ELEMENT METHOD FOR UNMANNED ELECTRIC VEHICLE APPLICATIONS 1 H. SURYOATMOJO, R. MARDIYANTO, G. B. A. JANARDANA, M. ASHARI Department of Electrical

### ELECTROMAGNETIC INDUCTION. Faraday s Law Lenz s Law Generators Transformers Cell Phones

ELECTROMAGNETIC INDUCTION Faraday s Law Lenz s Law Generators Transformers Cell Phones Recall Oersted's principle: when a current passes through a straight conductor there will be a circular magnetic field

### Question Number: 1. (a)

Session: Summer 2008 Page: 1of 8 Question Number: 1 (a) A single winding machine cannot generate starting torque. During starting the switch connects the starting winding via the capacitor. The capacitor

### 21.2 Electromagnetism

In 1820 Hans Oersted discovered how magnetism and electricity are connected. A unit of measure of magnetic field strength, the oersted, is named after him. Electricity and Magnetism How can an electric

### Just what is an alternator?

Just what is an alternator? An alternator is the device used to produce the electricity the car needs to run and to keep the battery charged. The battery is the heart of your electrical system. But you

### ANALYTICAL DESIGN OF AXIAL FLUX PMG FOR LOW SPEED DIRECT DRIVE WIND APPLICATIONS

ANALYTICAL DESIGN OF AXIAL FLUX PMG FOR LOW SPEED DIRECT DRIVE WIND APPLICATIONS K.Indirajith 1, Dr.R.Bharani Kumar 2 1 PG Scholar, 2 Professor, Department of EEE, Bannari Amman Institute of Technolog

### 694 Electric Machines

694 Electric Machines 9.1 A 4-pole wound-rotor induction motor is used as a frequency changer. The stator is connected to a 50 Hz, 3-phase supply. The load is connected to the rotor slip rings. What are

### Improving Alternator Efficiency Measurably Reduces Fuel Costs. BY MIKE BRADFIELD, MSME Remy, Inc.

Improving Alternator Efficiency Measurably Reduces Fuel Costs BY MIKE BRADFIELD, MSME Remy, Inc. This white paper is being provided as a service to the industry to promote better understanding of the importance

### Schedule of Events. Mech 1751: Introduction to Mechatronics. What is an actuator? Electric Actuators and Drives. Actuators. Dr. Stefan B.

Schedule of Events Week Date Content Assignment Notes Mech 1751: Introduction to Mechatronics Actuators 1 2 3 4 5 6 7 8 9 09/3 16/3 23/3 30/3 6/4 20/4 27/4 4/5 11/5 Introduction Design Process System Modelling

### To discover the factors affecting the direction of rotation and speed of three-phase motors.

EXPERIMENT 12 Direction of Rotation of Three-Phase Motor PURPOSE: To discover the factors affecting the direction of rotation and speed of three-phase motors. BRIEFING: The stators of three-phase motors

### Electromagnetic Induction and Faraday s Law

Electromagnetic Induction and Faraday s Law Solenoid Magnetic Field of a Current Loop Solenoids produce a strong magnetic field by combining several loops. A solenoid is a long, helically wound coil of

### DERATING OF THREE-PHASE SQUIRREL-CAGE INDUCTION MOTOR UNDER BROKEN BARS FAULT UDC : Jawad Faiz, Amir Masoud Takbash

FACTA UNIVERSITATIS Series: Automatic Control and Robotics Vol. 12, N o 3, 2013, pp. 147-156 DERATING OF THREE-PHASE SQUIRREL-CAGE INDUCTION MOTOR UNDER BROKEN BARS FAULT UDC 621.313.33:621.316.1.017 Jawad

QUESTIONSHEET 1 One mark for each of: when the pressure switch (A) is pushed, a current flows the electromagnet (B) is activated/switched on the armature (C) is attracted to the electromagnet the clapper

### Three-Phase Induction 208V Motor with MATLAB

EXPERIMENT Induction motor with Matlab Three-Phase Induction Motors 208V LL OBJECTIVE This experiment demonstrates the performance of squirrel-cage induction motors and the method for deriving electrical

### CHAPTER 31 SYNCHRONOUS GENERATORS

Source: POWER GENERATION HANDBOOK CHAPTER 31 SYNCHRONOUS GENERATORS Synchronous generators or alternators are synchronous machines that convert mechanical energy to alternating current (AC) electric energy.

### Axial Flux Permanent Magnet Brushless Machines

Jacek F. Gieras Rong-Jie Wang Maarten J. Kamper Axial Flux Permanent Magnet Brushless Machines Second Edition Springer Contents 1 Introduction 1 1.1 Scope 1 1.2 Features 1 1.3 Development of AFPM Machines

### Sharjah Indian School Sharjah Boys Wing

Read the instructions given below carefully before writing the fair record book. The following details are to be written on the LEFT HAND SIDE of the book. CIRCUIT DIAGRAM CALCULATIONS The remaining details

### INDUCTION MOTOR. There is no physical electrical connection to the secondary winding, its current is induced

INDUCTION MOTOR INTRODUCTION An induction motor is an alternating current motor in which the primary winding on one member (usually the stator) is connected to the power source and a secondary winding

### Human Energy Generation and Electrical Signal Measurement

Human Energy Generation and Electrical Signal Measurement Energy Generation and Usage Earth s Energy Balance Yearly energy resources (TWh) Solar energy absorbed by atmosphere, oceans, Earth[1] 751,296,000.0

### The Characteristics of LGE Linear Oscillating Motor

urdue University urdue e-ubs International Compressor Engineering Conference School of Mechanical Engineering 010 The Characteristics of LGE Linear Oscillating Motor Sangsub Jeong Wonsik Oh Hyuk Lee Sungman

### Photographs of large cities, such as Seattle, Washington, are visible reminders of how much people rely on electrical energy.

Photographs of large cities, such as Seattle, Washington, are visible reminders of how much people rely on electrical energy. Generating Electric Current How is voltage induced in a conductor? According

### Electric Drives CHAPTER1 LEARNING OBJECTIVES INTRODUCTION

CHAPTER1 Electric Drives LEARNING OBJECTIVES After the completion of this unit, students/readers will be able to understand: 1. What is a drive? Why electric drives are preferred over mechanical drives.

### Technical Developments in the Measurement of Commutator Profiles. Carbone of America. WMEA Tucson AZ. Roy Douglas Technical Manager

Carbone of America Technical Developments in the Measurement of Commutator Profiles WMEA Tucson AZ. Roy Douglas Technical Manager Content 2 1. Tools and Methods of Measuring Commutator Profiles (9) 2.

### Bistable Rotary Solenoid

Bistable Rotary Solenoid The bistable rotary solenoid changes state with the application of a momentary pulse of electricity, and then remains in the changed state without power applied until a further

### CHAPTER 19 DC Circuits Units

CHAPTER 19 DC Circuits Units EMF and Terminal Voltage Resistors in Series and in Parallel Kirchhoff s Rules EMFs in Series and in Parallel; Charging a Battery Circuits Containing Capacitors in Series and

### INDUCTION MOTORS 1. OBJECTIVE 2. SAFETY

INDUCTION MOTORS 1. OBJECTIE To study a 3-phase induction motor, by using its experimentally developed equivalent circuit diagram and by obtaining its basic characteristics: torque/slip, current/slip and

### Electromagnetic Induction (approx. 1.5 h) (11/9/15)

(approx. 1.5 h) (11/9/15) Introduction In 1819, during a lecture demonstration, the Danish scientist Hans Christian Oersted noticed that the needle of a compass was deflected when placed near a current-carrying

ELECTRICAL MEASURING INSTRUMENT CHAPTER 15 ELECTRICAL MEASURING INSTRUMENTS THE MOVING COIL GALVANOMETER The moving coil galvanometer is a basic electrical instrument. It is used for the detection or measurement

### 1. Replace the plugs with the cheap Autolite (25) copper-core plugs, set to 80 thou gap.

A recently encountered e-mail from Robert Calloway states that Tesla s bi-filar series-connected coil is effective in picking up radiant energy. In the light of that, and in the absence of further information

### Update. This week A. B. Kaye, Ph.D. Associate Professor of Physics. Michael Faraday

10/26/17 Update Last week Completed Sources of Magnetic Fields (Chapter 30) This week A. B. Kaye, Ph.D. Associate Professor of Physics (Chapter 31) Next week 30 October 3 November 2017 Chapter 32 Induction

### Electric Vehicle Mathematical Modelling and Simulation Using MATLAB-Simulink

IOSR Journal of Electrical and Electronics Engineering (IOSR-JEEE) e-issn: 2278-1676,p-ISSN: 2320-3331, Volume 12, Issue 4 Ver. I (Jul. Aug. 2017), PP 47-53 www.iosrjournals.org Electric Vehicle Mathematical