The dc motor is of vital importance for the industry today and is equally important for engineers to look into the working principle of dc motor in details that we have discussed in this article. Basics of dc motors for electrical engineers beginners. It is logical that the least expensive, lowest maintenance type. Explain what practical difference this makes in each motor s operation. Electric motor converts electric power into shaft power. The electric motor in its simplest terms is a converter of electrical energy to useful. Transformer is a nonrotational device and motor is a rotational machine. More than half of all electric energy generated goes to power electric motors.
The electric motor operation is based on the following points. An electric motor is a device converting electrical energy into mechanical energy usually a torque. These two electric motor designs are quite similar in appearance, but differ in the specific principle that makes the rotor move. The theory used in the work was collected by studying literature on how electrical motors work, and by simplifying the explanations to suit the intended reader.
Like generators, electric motors consist of a stator and a rotor and the three ingredients. Get motor rewinding procedure pdf file for free from our online library pdf file. We know about the activity of a capacitor in a pure a. However, there are also other types of motors that utilize electrostatic forces or piezoelectric effect.
At least one of the two magnetic field is generated by a solenoid. Dc, ac, and bldc motors introduces practical drive techniques of electric motors to enable stable and efficient control of many application systems, also covering basic principles of highperformance motor control techniques, driving methods, control theories and power converters. Electric motor is a device which converts electrical energy into mechanical energy. Motor controls basic theory quiz electrician exams. The handbook contains a wide array of topics and each topic is written by an authority on the subject. The module will present a number of different to pics. The principle of the electric motor is based on the fact that a current carrying conductor produces a magnetic field around it. This conversion is usually obtained through the generation of a. The magnet is spun by a 3 phase ac motor with no rotor voltage 4. When a capacitor is so introduced, the voltage lags the current by some phase angle. Induction motor theory jerry bednarczyk, pe course content introduction the ac induction motor is well suited to applications requiring constant speed operation. Electric motors and drives is intended for non specialist users of electric motors and drives, filling the gap between maths and theory based academic textbooks and the more prosaic handbooks, which provide useful detail but little opportunity for the development of real insight and understanding. In general, the induction motor is cheaper and easier to maintain compared to other alternatives. Motor start theory motor start torque performance is indicated by the motors locked rotor torque lrt figure.
To generate a constant drag on the disk necessary to limit its rotational speed, a strong magnet is placed in such a way that its lines of magnetic flux pass perpendicularly through the. All around us there are electrical devices that move things around. Ac motor theory entails the use of electromagnets with currents to create force, and therefore motion. Question 1 electromechanical watthour meters use an aluminum disk that is spun by an electric motor. There are many factors that affect the life expectancy of an ac induction motor or any electric motor. An electric motor is an electrical machine that converts electrical energy into mechanical energy. The modules listed in the overview are linked to the corresponding pages. There is even a little motor that is used to eject the removable disk from its drive. The text that was researched and compiled contains explanations of the motor parts, theory about electromagnetism and how current is used to make an electrical motor rotate. Synchronous ac motors use a permanent magnet rotor, while induction motors use an electromagnet rotor. The singlephase induction motor can be made to be selfstarting in numerous ways.
Dc motors although ac motors are used in most of the cases, dc motors have many applications and used for multipurpose applications. Practical electric motor handbook pdf by irving m gottlieb. The principle of an ac motor is that electric current is applied to electromagnets, creating a rotating magnetic field to convert electrical energy to rotation mechanical energy. The rotor will constantly be turning to align its magnetic field with that of the stator field. Basic design and theory of operation the alternating current ac induction motor is one of the most rugged and most widely used machines in industry.
When the motor is running and if the supply to the contactor coil fails, then motor will stop. Basic electrical theory overview of ac motors, transformers and measuring instruments instructor. Basics of dc motors for electrical engineers beginners on photo. The handbook of electric power calculationsprovides detailed stepbystep calculation procedures commonly encountered in electrical engineering. The basic idea of an electric motor is to generate two magnetic fields.
To understand the operating principle of dc motor we need to. This is a physics video that explains the basic principle of an electric motor generator. An885 ds00885apage 2 2003 microchip technology inc. The book deals with the fundamentals, theory, and design of conventional cars with internal combustion engines ices, electric vehicles evs, hybrid electric vehicles hevs, and fuel cell vehicles fcvs. An electric motors principle of operation is based on the fact that a.
It comprehensively presents vehicle performance, configuration, control strategy, design. A basic rule of thumb is that in an ac motor, as in an ac generator used for industrial power production, the magnet is on the rotor and the current 1. In synchronous ac motors, the speed of rotor is proportional to the stator, i. The 3phase set of currents, each of equal magnitude and with a phase. Electromechanical watthour meters use an aluminum disk that is spun by an electric motor. Physics principle of an electric motor physics youtube. In thermodynamics terms, this is simply converting work from one form to another. Fundamentals of electric motors and transformers idc technologies. In addition to providing basic information about ac motors in general, this course also includes an overview of. The induction motor is made up of the stator, or stationary windings, and the rotor. Other members of the family are the direct current dc motor or generator, the induction motor or generator, and a number of derivatives of all these three. These motors are known for their efficiency in maintaining the power of the overall system and can be used as stepper motors in some cases. A basic understanding of electricity and electrical systems is necessary for doe nuclear facility operators, maintenance personnel, and the technical staff to safely.
Other members of the family are the direct current dc motor or generator, the induction motor or generator, and a number. If an electric current carrying conductor is kept in a magnetic field, the. Question 1 if the ends of a wire loop are attached to two halfcircular metal strips, arranged so that the two strips almost form a complete circle, and those strips are contacted by two brushes which connect to opposite poles of a battery, which way will the wire loop rotate. Text headings in each module are linked to and f\ rom the table of contents for that module. Working or operating principle of dc motor electrical4u. Electric motor class 10, magnetic effects of electric. In the example, motor a produces twice as much torque during start as motor i. Most electric motors operate through the interaction between the motors magnetic field and electric current in a wire winding to generate force in the form of torque applied on the motors shaft. There are two major components of an ac induction motor. This module will cover the fundamentals of electricity in a practical way, and will not be complicated by complex theory and mathematical calculations. Another method is the capacitor start induction run motors. An ac motor of this type may be part of a pump or fan or connected to some other form of mechanical equipment such as a winder, conveyor, or mixer. This course is intended to prepare the target persons with the ability to understand and recognize different types, components, theory of operation and applications of all electrical motors. Working of electric motor mainly depends upon the interaction of magnetic field.
All of these motors work in more or less same principle. This conversion is usually obtained through the generation of a magnetic field by means of a current flowing into one or more coils. Other members of the family are the directcurrent dc motor or generator, the induction motor or generator, and a number of derivatives of all these three. Singlephase induction motor threephase induction motor singlephase induction motor there are probably more singlephase ac induction motors in use today than the total of all the other types put together. This portable document format pdf file contains bookmarks, thumbnails, and hyperlinks to help you navigate through the document. The rotor has salient poles and a cage so that it starts like an induction motor, and runs like a synchronous motor. Its operation is based on the principle that when a current carrying conductor is placed in a. His specialty is the design, operation, and maintenance of electric power distribution systems and large motor installations. Dc motor principle a machine that converts dc power into mechanical energy is known as dc motor. An induction motor also known as an asynchronous motor is a commonly used ac electric motor.
Read online now motor rewinding procedure ebook pdf at our library. Ed thornton is an electrical consultant in the electrical technology consulting group in engineering at dupont, in houston, texas. Uses soft magnet rotor that is magnetized by the application of current in the stator coils 3. When an electric current flows through a coil, a magnetic field is generated, the direction of which. This book, therefore, targets the large body of workers engineers and students reasonably versed in engineering concepts who feel the need for practical insights relating to electric motors. Motor speed relationship the synchronous speed of an ac motor is the speed of the rotating magnetic field set up by the stator winding synchronous speed rpm 120 x frequency divided by the number of poles. An electrical motor is a device that has brought about one of the biggest advancements in the fields of engineering and technology ever since the invention. An introduction to electrical motors basics course description. The synchronous electrical generator also called alternator belongs to the family of electric rotating machines. Electric motors for machines and mechanisms mits fab lab. Initially the notes included threewire electric power, including standard circuit theory.
To generate a constant drag on the disk necessary to limit its rotational speed, a strong magnet is placed in such a. Motor theory and practice what is the average ac induction motor life expectancy. The treatment throughout the handbook is practical with very little emphasis on theory. Ac induction motor speed control so what can we do to control the speed of an ac induction motor. The second law allows electric motors to have a theoretical efficiency of 100%. Module 6 dc motors this module describes the types of dc motors and includes discussions of speed control, applications, and load characteristics. This portable document format \pdf\ file contains bookmarks, thumbnails, and hyperlinks to help you navigate through the document. Mechanical energy what is an electric motor an electric motor is a device converting electrical energy into mechanical energy usually a torque. What is common to all the members of this family is that the basic. A current carrying conductor placed perpendicular to magnetic field experiences a force. The electric motor is a device which converts electrical energy to mechanical energy. In the case of a pmdc permanent magnet dc motor, motion is produced by an electromagnet armature interacting with a fixed field magnet housing assembly. Just about everything in ones life that whine, whirrs or clicks does so because an electric motor caused the motion.