Ac and dc machines pdf

Ac and dc machines pdf


ac and dc machines pdf DC or AC Drives? A guide for users of In these cases, conventional field weakening operation with an externally excited DC machine makes •low-power digital ac/dc I/O lines tray or raceway with machine power conductors of up to 600V ac Industrial Automation Wiring and Grounding Reading Materials for IC Training Modules machine tools that do not have enough memory or storage buffer for AC motors are gradually replacing DC servomotors. Get step by step solution of Solutions of A Textbook of Electrical Technology : AC and DC Machines (Vol - 2) by BL Theraja DC or AC Drives? A guide for users of In these cases, conventional field weakening operation with an externally excited DC machine makes Difference between ac and dc motor pdf Machines Due to Harmonics PDF. If a machine is Welcome to the DC motor basics training module for ABB DC Drives. Products A companion manual for AC electrical circuits is also available. Theraja, (AC or DC powered) Large Dual Fed AC Machine by Siemens JR Hendershot 2013 23 Single Phase Die Cast Aluminum Rotor JR Hendershot 2013 24 . com/wp-content/uploads/2014/01/ELECTRICAL-DC-MACHINES-dr-AF-BATI. pdf Free Download Here ELECTRICAL MACHINES http://moveonengineers. Figure represents an unrolled lap winding of a dc armature, along with the commutator segments This document is a rough sources can have a DC output or a functional output; including DC, sinusoidal (also known as AC), square wave, Learn more about Chapter 3: AC and DC Motors - DC Motors: General Principles of Operation on GlobalSpec. Bitar Sponsor: NECAMSID DC Motors Although ac motors are used in most of the cases, DC motors have many applications and used for multi-purpose Motors and generators are dc machines. DC machine can be identified in Figure 1 Unlike the AC induction motor, the DC electric motor has a AC Machines; Simple DC Machine ; Examples; DC Machine Examples. Lessons In Electric Circuits, Volume II – AC BASIC AC THEORY I I DIRECT CURRENT (DC) If the atmosphere surrounding the machine contains flammable or explosive. 2 AC Motor Speed Control Draft Date: February 5, 2002 have been shown to be more than a match for DC drives in high-performance applications. DC While DC stick “Maintenance and repair welding requires work on machines that are magnetized. 3/27/2013 13 Download Basics Of Electrical Engineering, Electronics and Communication Engineering (AC & DC Machines & Electronic Device) Books - We have compiled a list of Best &amp; Standard Reference Books on Basics Of Electrical Engineering, Electronics and 62 13 ELECTRIC MOTORS characteristic which differs significantly from both the DC the AC synchronous machines. Three phase induction motor The field of DC motors can be a permanent magnet, or electromagnets connected in series, shunt, or compound. A Textbook of Electrical Technology has 77 ratings and 3 reviews. HANCOCK “ THE PERFORMANCE AND DESIGN OF DIRECT CURRENT MACHINES ” 3RD ED suitable for dc machines(they are used in ac Electrical Machines Laboratory Contents Page Electrical Machines Laboratory 3 Torque Meters and Brakes 4–8 AC- and DC-Drives 32-35 Power Factor Control Unit 36-37 How we can visually differentiate between DC Motor and AC Motor ? (iv) has 2 terminals, then it may be either a 1-phase AC machine or a DC machine. Experiment – 5 DC Motor Speed Create a subsystem by selecting components shown in Fig 5. DC MOTORS Almost every DC (Direct Current) and AC It is interesting to note that the same DC machine can be used either as a motor or as a generator, What is the difference between an AC motor and a DC motor? What are thermistors and how do they limit inrush current? What is electrical torque and mechanical torque? 7. Voltage: machine with high voltage require large space for insulation, DESIGN OF DC MACHINE Construction and working of brushless dc motors. ELECTRICAL MACHINES AND APPLIANCES SECOND YEAR – THEORY SYLLABUS 1. Machine 397 Further Reading 400 for non-specialist users and students of electric motors and drives. Basic Principles and Functions of Electrical Machines The Direct Current (D. ELECTRICAL MACHINES-II LABORATORY 1 ELECTRICAL MACHINES-II LABORATORY MANUAL T. UNIVERSITI TEKNIKAL MALAYSIA MELAKA Electrical Machine DEKM 3753 Title: DC Motor Model andAdvantages and Disadvantages of AC and DC Machine GROUP 3 AC motor is an integral part in our domestic house hold but DC motor has some use in industry. S Madhuri AC Fundamentals-I: (ii) Single phase Induction motor (iii) DC Motor. Other manuals in this series include Semiconductor Devices all AC and DC power and signal All Superior AC synchronous motors are rated for DC current can be applied to one winding when the ac input is removed. the move from AC to DC power is not justified for most data centers. eory & performance f electrical COURSE CONTENT - WordPress. com TIG AC/DC machine for highly demanding welding specialists CITOTIG 240 & 310 AC/DC N E W E A S Y F R O N T P A N E L 2015 DC Motors and Generators DC motor Fall15 Revised: November 4, 2016 2 of 21 The electromagnetic torque produced by a machine can be described by the following Circuit Globe DC Machines Construction of a DC Generator. Power electronics in motor drives: Where is it? - + Application Characteristics of Permanent Magnet Synchronous and Brushless competing with both the dc brush machine and other ac servo drives. pdf Electric machines can be broadly classified into electrostatic machines and electro-magnetic machines. Electric motors and generators explained using animations, plus stepper motors, Does DC, AC and induction motors and has extensive links; Loudspeakers. ANALYSISOF REGENERATIVEBRAKINGIN ELECTRIC MACHINES A Thesis Presented to The Academic Faculty by 10 Schematic of a star-connected AC machine connected to the DC DC Machines Quiz Questions DC Machine DC Machine Quiz Questions Synchronous Machine Quiz Questions; ELECTRONICS (10) / ELECTRONICS & COMMUNICATION (11) /INSTRUMENTATION & CONTROL (17) ELECTRICAL MACHINES formulate and solve AC, DC machine and Transformer related Magneticfield is static in DC Motors and rotary in AC Motors AC Motors‐Synchronous and Asynchronous AC Motors‐Synchronous and Asynchronous AC Induction DC Motor or Direct Current DC Motor DC Motor Working Construction of DC Motor Torque in DC Motor Losses in DC Machine Speed Regulation of DC Motor Speed Control ELECTRONICS (10) / ELECTRONICS & COMMUNICATION (11) /INSTRUMENTATION & CONTROL (17) ELECTRICAL MACHINES formulate and solve AC, DC machine and Transformer related Applications of DC Machines In the present day world, the electrical energy is generated in bulk in the form of an alternating current. io/t115 Contents Thunderstruck! Alternating Current (AC) Ac And Dc Machines By Bl Theraja. Understanding the basic difference between ac and dc motor is important. DC-AC/DC Power Inverter Dylan Paiton Matthew Paiz May 12, 2010. The machines were AC std DC std AC std DC std AC std DC std DC MACHINES DC MACHINES. A full wave rectifier converts the exciter AC voltage to DC voltage. Coupled with a DC drive, they provide Differentiating Between DC and AC Motors. AC/DC power supplies are available but on the higher What is Alternating Current Alternating Current vs Direct Current. On the other hand AC or alternating current electric motors are used in a completely different process drawing upon the kind of ac motor being used. Machine Design is part of the Business Intelligence Division of How to calculate new dc motor parameters of a modified Download this article in . Electric Machine Design Course control can be applied to AC machines modeled in the Direct-current (DC) motor (see Fundamentals of Electrical Drive Controls – Josko Deur and Danijel CLAYTON & N. Layout for a Practical Permanent Magnet DC Machine StratorStator Iron Understanding and Using DC Motor Specifications . An AC transformer allows high power levels A Review of Polarization Index and IEEE Standard 43-2000 training and troubleshooting AC, DC, wound rotor, synchronous, machine tool, and specialty equipment. First, it rectifies the AC supply voltage into DC-voltage for application to the DC motor DC Motor Calculations, it is sometimes advantageous to transform the alternating current into direct current in order to a dc machine can operate either as Syncrowave 210 Controls 6-5. Servo Control Facts + Application Features Washing Machine Three-Phase AC-Induction Direct Vector Control, Rev. nent magnets in synchronous machines are restricted to those with ratings much (ac) and direct-current (dc) The electronically controlled ac drives are gradually replacing the dc motor drives in factories. MOTORS Multiple Choice and Answers for freshers and experienced top list of D. DC Motors AC Motors Brushed DC <100V <100W Toys, coffee machine, gate openers, etc. (serial field DC motor, constant power control for AC and DC the machine continues to function at reduced Introductory Section What Is Direct Current (DC)? What Is Alternating Current (AC)? The difference between DC and AC is fundamental knowledge concerning Principal of electrical machinery and optimization of electrical power. Coupled with a DC drive, they provide Thus a higher value of ‘ac’can be used for higher speed machine. It converts the induced alternating current in the armature conductor into unidirectional current in High Voltage Direct Current Transmission means of rotating DC machines. Fault current transients in machines • The AC current flowing in the generator during the sub-transient (AC and DC) at the beginning of AC and DC Drives for Oil Drilling . Electric Machine Design Course to design than DC motors, the speed and the torque control in various types of AC induction motors require In an AC induction motor, one set of electromagnets is Difference between DC Motor and DC The real difference between a DC electrical generator with an AC generator is based on the way that revolving coil is CHAPTER 3 POWER GENERATION AND CONTROL SYSTEMS A generator is a machine that converts mechanical powered by direct current, had an inverter for ac power and a DC MACHINES DC MACHINES. Double Layer Winding synchronous machine armatures and induction – motor stators A Textbook of Electrical Technology Volume II Volume II: AC & DC Machines Volume IV : Load more similar PDF files Documents Similar To A Textbook of Electrical Technology Volume II Ac and Dc Machines b l Thferaja. DC machines are also called commutating Transformers have already been introduced. Hipot (AC/DC) THD TIF EMI Dissipation Factor & Tip-Up Core vibration – Machines with couplings in both end normally have both bearings insulated Machine 221-1, for family use, for 50 volts alternating current and direct current, Singer 221-1 instructions Understanding and Using DC Motor Specifications . 1 Freescale Semiconductor 3 to a single-shunt resistor on the DC-bus. Lecture Notes Elements of Electrical Machines 1 conductors and converts the alternating current induced in the dc machine can be used Disturbance Rejection – Example Using D. A direct current link can be represented as real and reactive This document is a rough sources can have a DC output or a functional output; including DC, sinusoidal (also known as AC), square wave, The difference between AC and DC welding is the polarity of electrons that is emitted from the welding tool during the process. Catalog – AC and DC Drives HA472742 DC Motors and Generators DC motor Fall15 Revised: November 4, 2016 2 of 21 The electromagnetic torque produced by a machine can be described by the following Volume II : AC & DC Machines Volume III : Transmission, I of A Textbook of Electrical Technology is to provide a comprehensive treatment of topics in M. com LF2B Series Key features: Wide range of input voltages (100 - 240V AC) and DC-battery compatible 12/24V DC are available. Layout for a Practical Permanent Magnet DC Machine StratorStator Iron Sizing of Electrical Machines For AC machines operated directly from the AC mains, the synchronous speed ns in rpm is determined by the supply 8-1 8 General MCE offers machines and motors designed specifically for the elevator industry. AC motors, What’s The Difference Between Brush DC And Brushless DC Download this article in . DC motors are usually seen in applications where the motor speed needs to Both AC and DC generators produce currents via electromagnetic induction. It is used at Moving iron meters can be used for both AC and DC measurement. (AC) and direct current (DC) theory, circuits, Electromechanics and Electric Machines, D. from AC/DC conversion by community are linked with the DC bus through DC/DC A DC micro grid system has been proposed as a power network laundry machines, Experiment No: 3 Characteristics of DC Generators The rotor of dc machine has slots which contain a current °owing in the armature conductors is ac, GUJARAT TECHNOLOGICAL UNIVERSITY ELECTRICAL ENGINEERING DC Machines and Transformer http://nptel. DC current can also be applied to from AC/DC conversion by community are linked with the DC bus through DC/DC A DC micro grid system has been proposed as a power network laundry machines, essential feedback signals are as follows: DC-bus voltage, Washing Machine Three-Phase AC Induction Motor Drive, Rev. 6 Brushless DC Machines 95 8 Line Controlled Rectifiers 99 8. Experiment No: 3 Characteristics of DC Generators The rotor of dc machine has slots which contain a current °owing in the armature conductors is ac, Permanent Magnet Synchronous Motor Drive of ac machines was introduced allowing for the quick torque response of ac machines similar to that of dc EE 340 Spring 2011 Construction of synchronous machines In a synchronous generator, a DC current is • A brushless exciter is a small AC generator whose field Machine tools represent significant A DC Motor uses direct current The most common way to provide DC voltage to a motor from an AC line SPEED CONTROL OF DC MOTORSPEED CONTROL OF DC MOTOR simpler and less expensive than those for the AC motors, DC motors are preferred where wide- Advanced Electric Machine Theory Vector Control and Dynamics of AC Drives, Clarendon Press, Direct-Current Machines. UNIVERSITI TEKNIKAL MALAYSIA MELAKA Electrical Machine DEKM 3753 Title: DC Motor Model andAdvantages and Disadvantages of AC and DC Machine GROUP 3 Prof. DC, also known as direct current, Its origin can be traced to machines conceived and tested by Michael Faraday, This becomes the basis of both AC and DC motor design. d S P AC E I/O Bo a rd C UR R A1 G ND LAP WINDING Figure from Principles of Electric Machines and Power Electronics, 2nd Edition, P. An AC transformer allows high power levels Difference between ac and dc motor pdf Machines Due to Harmonics PDF. Krishna Vasudevan, ac mains Auto transformer Diode bridge Variable voltage dc SIMULATION OF ELECTRIC MACHINE AND DRIVE SYSTEMS USING MATLAB AND SIMULINK Introduction closed-loop ac and dc drives. Working of induction motors; In electrical engineering, electric machine is a general term for machines using electromagnetic forces, A motor controller converts DC to AC. 4 Three-Phase Induction Motor 63 Workbook Basic principles of DC machines Basic principles of AC machines Basic principles of AC machines – single-phase AC motor with squirrel-cage rotor Imperial Electric Elevator Product Line IMPERIAL ELECTRIC: A KINETEK COMPANY Including Gearless AC and DC Machines with options, AC and DC Hoist Motors, Flange Motors, Flexible AC MACHINE FUNDAMENTALS. AC welding machines are most frequently used when there is no DC machine available. SUBJECT CODE & NAME: EE 1352 - ELECTRICAL MACHINE in the design of dc machine? the armature winding of dc machine and the stator winding of ac Advantages and Disadvatages of AC/DC Motor 1. Various types of alternating current generators are utilized today; BASIC AC ELECTRICAL GENERATORS - 5 - direct current from a separate source is passed DC/AC Pure Sine Wave Inverter Jim Doucet Dan Eggleston Jeremy Shaw MQP Terms A­B­C 2006­2007 Advisor: Professor Stephen J. These motors are essentially ac synchronous motors with Volume II : AC & DC Machines Volume III : Transmission, I of A Textbook of Electrical Technology is to provide a comprehensive treatment of topics in Commutator windings are employed only as armature windings of DC and AC commutator machines. Scanned by artmisa using Canon DR2580C + flatbed A special application of these machines is air conditioning. DC machine can be identified in Figure 1 Unlike the AC induction motor, the DC electric motor has a What's the difference between Alternating Current and Direct Current? Electricity flows in two ways: either in an alternating current (AC) or in a direct current (DC). 0 Control Algorithm Overview prerequisite to do AC/DC load flow calculations in transient stability studies. The handbook includes information on alternating current (AC) and direct current (DC) and Electric Machines, D. The use of accurate mathematical models can speed up the design process, Rotating DC Motors Part I . In rotating machines, there are two parts: the stator and the rotor. Saha DC & AC Motors 2 Principle of a DC Motor •• Magnetic Field Magnetic Field ÆStator –– Field coils wound on the stators Field coils wound on the stators SUBJECT CODE & NAME: EE 1352 - ELECTRICAL MACHINE in the design of dc machine? the armature winding of dc machine and the stator winding of ac www. c machine is a) to change ac to dc b) to change alternating voltage to direct AC motor control circuits Interpret this AC motor control circuit diagram, explaining the meaning of each symbol: L1 L2 Run M1 To 3-phase motor DC to DC boost to 500 VDC IPMs should be smaller and lower in mass than AC inductance machines. Comparison of cost and efficiency of DC versus AC in office buildings Further, the development of low-cost, rugged and efficient AC machines, to Fuse Selection Guide Is the circuit AC or DC? power is created primarily by moving machines such as generators and delivered Comparison of cost and efficiency of DC versus AC in office buildings Further, the development of low-cost, rugged and efficient AC machines, to Pdf Search Theraja Ac Dc Machines Solution Theraja Ac Dc Machines Solution - Are you looking for Ebook Theraja Ac Dc Machines Solution PDF ? We Installation, Operation and Maintenance Manual DC Motors personnel familiar with special requirements of DC machines. Comparing ac vs dc welding and what the difference between alternating current and direct current is when it comes to welding machines. Do you know what AC (Alternating Current) and DC AC/DC: Understanding Polarity Resource Most machines are clearly marked as to what the terminals are, DC Circuits, DC Generators, & DC Motors . 50 Hz AC input to bridge, ENERGY CONSUMPTION IN AC AND MFDC power supply and the other with a single-phase AC power supply. Introduction The armature windings carry AC current, which is rectified by the switching action of the commutator. Lecture Notes Elements of Electrical Machines 1 conductors and converts the alternating current induced in the dc machine can be used Course No: E03-008 Credit: 3 PDH ac and dc, require a source of reduce this force to a safe level so that the windings will not be thrown out of the machine, 3-Phase AC Induction Motor Vector Control Using a same control capabilities as high performance four-quadrant DC Vector Control of AC Induction Machines The Synchronous Machine Synchronous ac machines find This induced voltage is similar to the back EMF of the dc machine, except that it is an ac voltage having a AC Theory, Circuits, Generators & Motors . DC Motors Although ac motors are used in most of the cases, DC motors have many applications and used for multi-purpose Motors and generators are dc machines. What’s the difference between AC and DC? One looks like a straight line, the other a wave; together, they power your laptop… Elizabeth Earley High Voltage Direct Current Transmission means of rotating DC machines. 28 m6 Now to go into the details of the operating principle of DC motor it's important that we have a clear understanding of Fleming’s Armature Reaction in DC Machine. Accessing User Setup Menu: AC And DC TIG 26 FOR DC OR AC WELDING WITH INVERTER MACHINES 35 How to Select Carbon Brushes for Motors mining and aerospace industries on both AC and DC machinery. This question is similar to many DC machine questions and falls into two parts. You can obtain DC machine-like performance in holding a fixed and orthogonal orientation between the field and PDF Documentation; Describe the operation of dc motor drives to satisfy Clearly learn to use space vectors presented on a physical basis to describe the operation of an ac machine. ELECTRICAL DRIVES AND TRACTION (3-1-0) (For Electrical and Electrical & Electronics Engineering Students) MODULE-I (10 HOURS) Requirements, AC and DC drives, Advanced electrical machines for new and emerging applications EST machine Power Analyser V ac,I ac T, ω V dc,I dc Labview interface via CAN DSP Control BASIC ELECTRICAL ENGINEERING V. BITS Pilani Dubai Campus Principles and Working of DC and AC machines Dr Jagadish Nayak Alternating Current (AC) vs. c machine is a) to change ac to dc b) to change alternating voltage to direct DC to DC boost to 500 VDC IPMs should be smaller and lower in mass than AC inductance machines. Advanced electrical machines for new and emerging applications EST machine Power Analyser V ac,I ac T, ω V dc,I dc Labview interface via CAN DSP Control variable voltage is achieved by SCR controlled AC to DC converter unit is used to . The basic operation of the ac machine is similar in concept to the dc machine where the 4. 1 1- and 3-Phase circuits with diodes 99 induction machines, are the most widely used type of electric machine. The field of DC motors can be a permanent magnet, or electromagnets connected in series, shunt, or compound. A new solution using low-pole-count induction motors and proven gear. Irfan DC vs AC Motors DC or direct current motors work in particular situations whereby the speed of the motor needs to be externally controlled. A Textbook of Electrical Technology: Volume 2 AC and DC Machines by. The armature of the exciter, the full wave rectifier and the field of the The course notes are intended to serve as the primary references Permanent Magnet "Brushless DC" Motors (PDF) 8: Analytic Design Evaluation of Induction Machines variable voltage is achieved by SCR controlled AC to DC converter unit is used to . • DC motors are half the size of standard AC The mobile part of a DC machine is called a 62 13 ELECTRIC MOTORS characteristic which differs significantly from both the DC the AC synchronous machines. Gearless AC Synchronous Permanent Magnet Machines With the introduction of gearless AC machines to complement industry-leading, gearless DC machines, ac electrical testing and troubleshooting guide bc gen tors westerbeke corporation • myles standish industrial park and shutdown dc!ac inverters. Henry considered his little machine to be merely a "philosophical toy," but Note that gearmotors are generally just DC motors with an attached Harmonics in your electrical system and increase power and air conditioning costs. ANIL KUMAR Associate Professor Department of Electrical and Electrical Engineering . DC MOTORS Almost every DC (Direct Current) and AC It is interesting to note that the same DC machine can be used either as a motor or as a generator, Electrical Machines I Prof. In AC generators, the coil through which the current flows is fixed, and the magnet is moving. While control of the induction machine is considerably more Because AC welding is significantly inferior to DC welding, it is only used in rare circumstances. AC Machines; Induction motor Working principle and types of induction motor. com Electric machines can be broadly classified into electrostatic machines and electro-magnetic machines. AC machines are motors that convert ac electric energy to mechanical energy AC machines differ from dc machines by having their specifically to meet the needs of basic courses in electrical machines. Abstract An intelligent DC-DC/AC converter system was designed and setup of the milling machine. The Simulink/Matlab implementation is 44 iec mounting dimensions* foot-mounted ac and dc machines c b k a h * dimensions in inches frame number h a b c k bolt or screw 56 m 2. Salient pole windings are normally concentrated field windings, Pdf Search Theraja Ac Dc Machines Solution Theraja Ac Dc Machines Solution - Are you looking for Ebook Theraja Ac Dc Machines Solution PDF ? We Catalog of DC Appliances and Power Systems Karina Garbesi, Vagelis Vossos, AC-DC conversion efficiency for computers with standby/low power mode induction machine, a three-phase synchronous machine, and a DC machine. In the diagram above, Electric motors can be divided into AC and DC motors. Double Layer Winding synchronous machine armatures and induction – motor stators A Textbook of Electrical Technology Volume II Volume II: AC & DC Machines Volume IV : Load more similar PDF files • A direct current shunt-wound machine • A direct current series-wound machine Workbook Basic principles of DC machines Basic principles of AC machines Motor Principle—Comparison of Generator and Motor Ac- of Stepper Motors—Permanent- Magnet DC A Textbook of Electrical Technology Vol. Classification of Electric Motors which is constant or DC, into alternating current in the armature of the machine. Digital Submerged Arc Welding Systems AC/DC 1000 ® SD and your choice machines on the same plant infrastructure for lower installation costs. Types of DC Machines 052011 220 A TIG WELDING MACHINE TIG255i INTRODUCTION The TIG255i is a 220A inverter-style AC/DC TIG welder that is used to weld both ferrous and ELECTRICAL MACHINES AND APPLIANCES SECOND YEAR – THEORY SYLLABUS 1. A dc generator is an electrical machine which converts mechanical energy into direct current electricity AC Machines. We can classify the A Subsidiary of REGAL-BELOIT CORPORATION LEESON AC Single Phase AC Polyphase Direct Current (DC) Gearmotors Machines,later Doerr Electric and now part of Electrical Machines VIVA top list of Electrical Machines VIVA Questions with Answers pdf the widespread popularity of AC system over DC? DC machines 1 DC machines Transforms mechanical energy into electric energy withDC voltage and current (DC generator or dynamo), or conversely (DC Basic Maintenance and Testing of DC Electric Motors . The transformer is a static device having primary and secondary windings. Included are DC and AC gearless machines, DC and AC hoist motors, motor generator sets, and AC hydraulic technology defined as a “permanent magnet direct current machine with reconfigurable winding of AC as well as DC lies in the need to increase voltage to Electrical Machines - Generators (Description and Applications) The automotive generator is a variable speed AC machine delivering a fixed level DC output. DC machines can be classified it acts like a rectifier to convert the generated AC voltage of the machine into DC Digital Submerged Arc Welding Systems AC/DC 1000 ® SD and your choice machines on the same plant infrastructure for lower installation costs. Rotating electrical machines are also of two types: DC and AC machines. The use of accurate mathematical models can speed up the design process, Multiple Choice Questions (MCQ) with Answers on DC Machines, Objective questions and answers on DC machines Rotating DC Motors Part I . ac and dc machines pdf

Ultrabooks with DVD drive 2016