Guide to AC and DC Motors - Theory and Operation

 

Written by: Tarun Goel • edited by: Lamar Stonecypher

Most rotational applications in industry and manufacturing depend on electric motors. Our day to day life depends on electronic and electrical devices, and they, too, in turn depend on electric motors. In this guide, we look at AC and DC motor designs and operational theory.

• Varying electric and magnetic fields result in rotary motion, and that is the principle used by most modern motors. Today we have various kinds of motors like conventional motors, brush-less motors, stepper motors, ball bearing motors, etc. These motors are used not only in heavy machinery but in the domestic appliances as well. Through this guide we will discuss various aspects related to working with AC and DC motors. How are motors designed? What needs to be considered before choosing a motor for particular operations? How do motors work? We have listed articles that will answer all your questions. These articles will equally help a practicing electrician and a young student trying to find out answers for the questions posed by his curious mind.
  
• Types of Electric Motors
• Although there are different types of motors available, the basic principle and working methodology of all motors is almost the same. The latest electronic technology has made things better in recent years and that is why today we have more different types of motors. We need not to rely on the conventional motors for all our work, and depending upon the type of work we want our machine to perform, we can select an AC or DC motor accordingly. Through the articles listed in this section, we will find detailed information about the working theory and operation of different types of AC and DC motors.
• Classification and Uses of Alternating Current Motors
• A.C Induction Motor Design and Operating Principles
• Working and Types of Stepper Motors Explained
• How Do Universal Motors Work?
• Linear Induction Motors - Applications and Future Scope
• Fundamentals of Slip Ring Motors Explained
• Understanding the DC Series Motor
• From Operations to Maintenance

Now that we know about different types of AC and DC motors, we will now see how motors rotate, how can we make them efficient, and what lies inside them that make them rotate the heavy blades of large machines so easily. These articles can be of great help to practicing engineers, electricians, and students because they give detailed and in-depth information about AC and DC motor designs and operations, which are very helpful in the field. Learn how we can start an induction motors in different ways and what the important factors are that we need to consider while repairing AC and DC motors. You will also get to know about easy ways to repair minor flaws with your motors. After all you do not want to look like a motorcyclist who has a flat tire on a deserted road with no knowledge of how to use a puncture kit. Learn more about working with the electric motors through the listed articles.

• Starting Methods for Induction Motors
• Working with the Electric Motors - Repair and Maintenance Works
• RPM Measurement of DC Motors
• Controlling Speed of a Universal Electric Motor
• Motor Failure Analysis: Common Causes and Remedial Measures
• How to Work With Self Starting Induction Motors?
• Working with a Slip Ring Motor
• Switching Synchronous Motors Through Electronic Circuits
• Construction of Squirrel Cage Induction Motors Explained
• Working with a DC Brushless Motor
• Working of a Magnetic Repulsion Motor Explained
• Synchronous Motor Theory - Operation and Construction
• Modern Age Electric Motors
• Modern day electric motors might look like a robotic invention for someone who has never worked on anything other than a conventional motor. Synchronization of motors, electronic control of motors, working with changing voltages, and varying motor speed according to the operational requirement are some of the benefits of modern technology. Things have become easy with changing times, and modern age motors are capable of doing better and challenging tasks than their predecessors. If we look back into the time and history, we will find that AC and DC motors have undergone phenomenal changes in the last few decades and the speed with which the technology is growing, we will see powerful and efficient motors running our equipment in future, too. Learn more about the latest technology through articles listed in this section.

• Running a 60Hz Motor on 50Hz Supply
• Capacitor Start Induction Run Motors
• High Torque DC Motor Speed Controller Unit Explained
• Speed Control of Slip Ring Induction Motors
• Electronic Logic Gates - The Intelligence Gateway in Machines
• The listed articles are written by experts, practicing electricians, and mechanical engineers. These articles give detailed insight into almost everything that concerns a person working with AC or DC motors. Are there any other topics concerning motor design and construction that you would like to see covered at Bright Hub? If so, please include your suggestions in the comments section below. Please note that comments are moderated and may take some time to appear.
   
• 

Lab shows powerful, possible next step in electric motors

 

Dr. Chenjie Lin, a postdoctoral researcher, was among those who demonstrated the double-stator switched reluctance machine at the ARPA-E Energy Innovation Summit.

A team from the Renewable Energy and Vehicular Technology Laboratory (REVT) at UT Dallas was one of a few research groups selected for advanced participation in a Department of Energy conference aimed at presenting the next generation of energy technologies.

The DOE's Advanced Research Projects Agency-Energy (ARPA-E) program hosts an annual summit in Washington, D.C., for researchers, entrepreneurs, investors, corporate executives and government officials to share transformational research funded through the program.

Dr. Babak Fahimi, professor of electrical engineering in the Erik Jonsson School of Engineering and Computer Science and director of REVT, has received $2.8 million through an ARPA-E program aimed at reducing rare earth metals, which are used in motors of electric vehicles. The metals are expensive, difficult to find and are usually imported into the United States from countries such as China. In addition, the mining process for these metals releases significant amounts of pollution into the atmosphere.

Dr. Chenjie Lin, a postdoctoral researcher, was among those who demonstrated the double-stator switched reluctance machine at the ARPA-E Energy Innovation Summit.

REVT members demonstrated electric motors or generators that eliminate rare earth metals. Typical motors are powered through the electromagnetic interaction between a rotor, which contains rare earth metals and rotates, and another part known as a stator, which is stationary but houses electromagnetic sources. The REVT solution, called a double-stator switched reluctance machine (DSSRM), has two stators, one on either side of the rotor, that cause an electromagnetic reaction that produces power. This approach produces significantly greater power and torque at a given size and weight than traditional motor technologies without the use of permanent magnets.

"The transformative nature of our motor technology stems from a novel magnetic configuration, which significantly reduces the radial forces while increasing the motional forces by a factor of three," Fahimi said. "This technology also benefits from high levels of fault tolerance, low-cost manufacturing and low acoustic noise. I strongly believe this technology is highly appealing to automotive, oil and gas, and renewable energy industries."

Besides delivering more power and torque than competing technologies, this machine could be manufactured entirely in the United States, which would eliminate the pollution from mining rare earth metals, while also significantly reducing the amount of air pollution released through electric vehicle emissions. Other applications of this technology are airplanes, fans, pumps, wind generators and robots.

The research, first funded in 2012, has one patent pending. At the conference earlier this year, REVT members demonstrated the technology to potential commercial licensees.

Team members who demonstrated the technology included Pete Poorman, assistant director of corporate relations, and Drs. Wei Wang and Chenjie Lin, postdoctoral researchers in the lab.

"Having the opportunity to present at the ARPA-E Energy Innovation Summit was a huge opportunity to further our work," Poorman said. "Being one of the few projects selected for the round-table discussion and congressional reception is both an honor and an acknowledgement of the excellent work being done in the REVT lab."

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The above story is based on materials provided by University of Texas at Dallas. Note: Materials may be edited for content and length.