Motor design and, even more importantly, motor choice and use practices are an important area of potential energy conservation. Starting and running torque are the first parameters to consider when sizing electric motors. Small electric motors are also inherently less e cient more like 50%. How does a threephase alternating current induction motor work. Motor control circuits motor control circuits are an effective way to reduce cost by using smaller wire and reducedamperage. The fan blows air over the motor s exterior for additional cooling.
What is common to all the members of this family is that the basic. Wedge the tip of a flatblade screwdriver underneath the thin metal tabs, then pull up gently on the handle to lift them enough to loosen the coiled wire. If the vibration stops, look for an electrical unbalance. For, example, size 11 mean the mounting face of the motor is 1. Rotates a number of degrees with each electric pulse. The fan is covered by a shroud to prevent anyone from touching it.
The first device used to stop and start electric motors was a simple knife blade. Rapid drop below 50% load us doe 27 unep 2006 assessment of electric motors motor load motor load is indicator of efficiency equation to determine load. It takes, however, the point of view that good application of a motor must rely on understanding of its operation. They consume no petroleumbased fuel and produce no tailpipe emissions.
Electric motor controls once the proper motor is selected, understanding the many various control devices available and their uses and limitations becomes an important part related to reliable operation and protection of the motor and the personnel using the motor. The type of motor that is used worldwide with a greater percentage. There are many types of ac motors, but this course focuses on threephase induction motors, the most common type of motor used in industrial applications. The rotor of an induction motor can be a squirrel cage rotor or wound type rotor. Evs also known as plugin electric vehicles derive all or part of their power from electricity supplied by the electric grid. Efficiency of electric motors motor part load efficiency designed for 50100% load most efficient at 75% load. In an induction motor, the electric current in the rotor needed to produce torque is obtained via electromagnetic induction from the rotating magnetic field of the stator winding. Have fun performance of the system compared with motor performance based on data sheet cim motor also known as chiaphua and atwood stall torque stall 347 ozin 2. The largest collection of symbols in the network in pdf format. Some are standardized versions for generalpurpose applications. At least one of the two magnetic field is generated by a solenoid carrying a current.
There are, of course, two broad categories of motors, ac and dc. 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. 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. Training package for basic principles of servo motor drive technology tp 1421. Thus, the first and most important step in electric motor selection is determining load characteristics torque and speed versus time. The motors rotation has several direct relationships to these.
The main design difference between a brushed and brushless motors is the replacement of mechanical commutator with an electric switch circuit. Dec 17, 2015 a motor that reverses the direction of an electrical current at regular times is called an alternating current motor, or more commonly known as an ac motor. The basic idea of an electric motor is to generate two magnetic fields. 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 motors and drives fundamentals, types and applications third edition austin hughes senior fellow, school of electronic and electrical engineering, university of leeds amsterdam boston heidelberg london new york oxford paris san diego san francisco singapore sydney tokyo newnes is an imprint of. These three parts use the attractive and repulsive forces of electromagnetism, causing the motor to spin continually as long as it receives a steady flow of electric current. Though configurations vary, the stator is most often a permanent magnet or row of magnets lining the edge of the motor casing, which is usually a round plastic drum. This elearning module provides a basic understanding of three phase induction motors. The motor being dissected here is a simple electric motor that you would typically find in a toy.
The shaft or spindle of a stepper motor rotates in discrete step increments when electrical command pulses are applied to it in the proper sequence. Furthermore, the electric motor is the primary component that powers blowers to move air. Sep 27, 2012 read about learning 101 basics of motor control starters. Electrical motors ppt electric motor engines free 30. However, there are also other types of motors that utilize electrostatic forces or piezoelectric effect. Motor winding 1 is distributed between the top and bottom stator poles, while motor winding 2 is distributed between the left and right stator poles. Leeson electric also produces permanentmagnet direct current motors. The rotor will constantly be turning to align its magnetic field with that of the stator field. The electric motor operation is based on the following points. The maximum torque is limited by the current rating of the motor and it is obtained at zero speed startup. To better understand, imagine the following situation. If the disconnected motor still vibrates, remove power from the motor. A linear motor is an electric induction motor that produces a linear force instead of a rotation. A servo motor is an electrical device which can push or rotate an object with great precision.
Stepper motor basics a stepper motor is an electromechanical device which converts electrical pulses into discrete mechanical movements. An introduction to electrical motors basics course description. The name vector control originates from the basic principle of this type of. Take two bar magnets and keep the poles facing each other with a small space in between. If you want to rotate and object at some specific angles or distance, then you use servo motor. Electrical motors basic components electrical knowhow. Adaptable can be used anywhere automatic can be controlled with automatic devices. Electric motors basics the hvac industry depends heavily on the electric motor. It is just made up of simple motor which run through servo mechanism.
Aevs all electric vehicles are powered by one or more electric motors. A subsidiary of regalbeloit corporation with leeson. Basics of dc motors for electrical engineers beginners on photo. Virtually all electrical motors use magnetic field rotation to spin their rotors. Motor control circuits motor control circuits are an effective way to reduce. To do this, a motor must be selected that is capable of starting the equipment, bringing it up to operating speed, and driving it at the necessary loading speed as long as required without excessive heating. Here we can introduce the analogy between a transformer and a motor that is a motor is like a transformer with a moving secondary. The following is a brief description of the information presented in each module of the handbook. You can see that this is a small motor, about as big around as a dime. Use a screwdriver to pry open the tabs on the brush pads. At least one of the two magnetic field is generated by a solenoid. Uses soft magnet rotor that is magnetized by the application of current in the stator coils 3. Whatever the application, the function of the contactor is always the same. Dependable if chosen properly they give little trouble.
Like most motors, an ac induction motor has a fixed outer portion, called the stator and a rotor that spins inside with a carefully engineered air gap between the two. Motor a motor is an extended version of a transformer. Ohms law is the basic formula used in all ac and dc electrical circuits. Motors electric motors, both ac and dc types, come in many shapes and sizes. Electric motor basics training video convergence training. These electrical devices are also used for the purpose of stopping, reversing and protecting electric motors. Senior fellow, school of electronic and electrical engineering. Or, as defined by nema, to repeatedly establish and interrupt an electrical power circuit. Introduction motor starters are one of the major inventions for motor control applications. This type of motor uses opposing and attracting magnetic forces to propel the ac through the motor.
Chapter 2 motor basics electromagnetism rotor rotation chapter 3 nema motors motor designs motor enclosures chapter 4 siemens motors nema motors iec motors above nema motors if you do not have an understanding of basic electrical concepts, you should complete basics of electricity before attempting this. Lastly, the electric motor powers a pump to move water for chilled water and hot water applications. Explain how this motor can be operated as either a synchronous motor or a plain induction motor. Basic principle the electric motor operation is based on the following points. Basics of dc motors for electrical engineers beginners. Some common types of single phase motors are the shaded pole motor, the split phase motor, the permanent split capacitor motor also called the single value capacitor motor, and the two value capacitor motor. So if you know two of the three characteristics, your can calculate the third one. Feb 02, 2015 visit to view the full video and purchase access to our other industrial maintenance courses. The speed of the motor is the same as that of the load, so the load friction is the friction the motor must overcome, and load inertia is what the motor sees. Electric motor selection is also based on mission goals, power available, and cost. As the name suggests, a starter is an electrical device which controls the electrical power for starting a motor.
Powering industry since replacing the steam engine from tiny hysteresis motors that drive electric clocks to huge synchronous motors that develop more than 50,000 hp, the alternating current ac motor has become an indispensable part of everyday life. For consultation and interpretation of components, devices and electrical and electronic circuit. Physics principle of an electric motor physics youtube. Motor speci cations usually involve several quantities. Volume 1 of 4 module 1 basic electrical theory this module describes basic electrical concepts and introduces electrical terminology. A single phase motor will not start on and must have help. Electric motor systems consume 20% of all energy generated in the united states, 57% of all electrical energy, and 70% of electrical energy consumed by industry. The dc motor is the oldest member of the electric motor family.
It also contains information about motor standards and application. The basic principles of electromagnetic induction were discovered in. There are magnets attached to both an external stationary stator, and an internal rotor. The working of an electric motor is based on the fact that a current carrying conductor produces a magnetic field around it. The phase relation between the rotor and stator magnetic field i. Like a unipolar motor, bipolar motors can be single stepped with two different control. Electric motors basics hvac easy tips for learning 101. A contactor can stand on its own as a power control device, or as part of a starter. This is accomplished by unrolling the stator and rotor. Nema sets standards for many electrical products, including motors. Motors and power systems there seems to be a lot of confusion about the voltage standards for motors and why they are structured the way they are. On some motors, there may be as many as 1216 tabs in total. Induction motors were invented by nikola tesla in 1888 while he was a college student.
Inserted into the stator is the rotor, usually consisting of. The rotor takes the form of a moving carriage known as the forcer. The rotor is a permanent magnet with 6 poles, 3 south and 3 north arranged around its circumference. Unit 1 basic principles of motor controls unit 1introduction this unit discusses the basic concepts of motor control, including motor control language and the types of wiring diagrams used. An introduction to electric motors stmicroelectronics. The rotor has salient poles and a cage so that it starts like an induction motor, and runs like a synchronous motor. Contactors are used in applications ranging from the light switch to the most complex, automated industrial equipment. A useful introduction to electric motors electrical. Sep 27, 2012 learning 101 basics of motors and motor controls. The electrical science handbook consists of fifteen modules that are contained in four volumes. The stator known as the platen in a linear motor, is a track of flat coils of copper or aluminum. Describe how a squirrel cage motor is built, and classify it as either an induction motor or a synchronous motor. The book is mostly concerned with application of motors, rather than on design or production. Try to bend the tabs as little as possible to avoid damaging them.
The magnet is spun by a 3 phase ac motor with no rotor voltage 4. If the motor does not run, the machine or device will not function. They receive electricity by plugging into the grid and store it in batteries. Introduce electric motor technology and its role in. Therefore, the total inertia is the load inertia plus the motor inertia. Tefc motors can be used in dirty, moist, or mildly corrosive environments. The motor is controlled by applying a voltage to the motor leads. Contactors are used by electrical equipment that is frequently turned off and on opening and closing the circuit, such as lights, heaters, and motors. This is a physics video that explains the basic principle of an electric motor generator.
Electric motors and power systems and electric motors and voltage edward cowern, p. Scroll to the bottom to watch the youtube tutorial on this article the induction motor is the most common type of electrical motor used in industry, and its used in pretty much everything, from elevators. Electrical, mechanical, and thermal motor characteristics define the frame needed for effective motor protection running stage, starting stage, and lockedrotor conditions serve to determine the main motor parameters motor heating and thermal damage motor characteristics depend on both positiveand negativesequence current in the. 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. Motors the basics of motors it is important to select the motor that will help assure optimum performance of the equipment to be driven. Additionally, electric motors drive compressors to compress refrigerant. Electric motor designs can vary quite a lot, though in general they have three main parts. From the outside you can see the steel can that forms the body of the motor, an axle, a nylon end cap and twobattery leads. Scribd is the worlds largest social reading and publishing site. An ac motor of this type may be part of a pump or fan or. Basics of brushless dc motors bldc motors construction. The importance and scope of the electric motor in modern life is attested to by the fact that electric motors, numbering countless millions in total, convert more energy than do all our passenger.
The electric motor is, of course, the very heart of any machine it drives. The direction is changed by reversing the polarity on the leads. Electrical designers use it to determine how much voltage is required for a certain load, like a motor, a computer, or even a house full of appliances. The beginnings of the electric motor are shrouded in mystery, but this much seems clear. This reading is a very brief introduction to four most basic types of electric motors. 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. Find out here with this article on induction motors. The primary that is not moving is called stator and the secondary that is moving is called rotor. If motor is used is dc powered then it is called dc servo motor, and if it is ac. A totally enclosed fancooled tefc motor is similar to a tenv motor, but has an external fan mounted opposite the drive end of the motor. Gear drive the mechanical linkage between the load and motor in a gear drive, figure 4.