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Dual-rotor Permanent Magnet Induction Motor
A dual-rotor motor is a motor having two Rotor (electric), rotors within the same motor housing. This rotor arrangement can increase power volume density, efficiency, and reduce cogging torque. Stator on the outside In one arrangement, the motor has an ordinary stator. A squirrel-cage rotor connected to the output shaft rotates within the stator at slightly less than the rotating field from the stator. Within the squirrel-cage rotor is a freely rotating permanent magnet rotor, which is locked in with rotating field from the stator. The effect of the inner rotor is to reenforce the field from the stator. Because the stator slips behind the rotating magnetic field inducing a current in the rotor, this type of motor meets the definition of an induction motor. Stator between rotors In another arrangement, one rotor is inside the stator with a second rotor on the outside of the stator. The photo labelled FIG. 8 is from a patent application. It shows two rotors assembled into a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rotor (electric)
The rotor is a moving component of an electromagnetic system in the electric motor, electric generator, or alternator. Its rotation is due to the interaction between the windings and magnetic fields which produces a torque around the rotor's axis.Staff. "Understanding Alternators. What Is an Alternator and How Does It Work." N.p., n.d. Web. 24 November 2014 . Early development An early example of electromagnetic rotation was the first rotary machine built by Ányos Jedlik with electromagnets and a commutator, in 1826-27. Other pioneers in the field of electricity include Hippolyte Pixii who built an alternating current generator in 1832, and William Ritchie's construction of an electromagnetic generator with four rotor coils, a commutator and brushes, also in 1832. Development quickly included more useful applications such as Moritz Hermann Jacobi's motor that could lift 10 to 12 pounds with a speed of one foot per second, about 15 watts of mechanical power in 1834. In 18 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Power Volume Density
Power density, defined as the amount of power (the time rate of energy transfer) per unit volume, is a critical parameter used across a spectrum of scientific and engineering disciplines. This metric, typically denoted in watts per cubic meter (W/m3), serves as a fundamental measure for evaluating the efficacy and capability of various devices, systems, and materials based on their spatial energy distribution. The concept of power density finds extensive application in physics, engineering, electronics, and energy technologies. It plays a pivotal role in assessing the efficiency and performance of components and systems, particularly in relation to the power they can handle or generate relative to their physical dimensions or volume. In the domain of energy storage and conversion technologies, such as batteries, fuel cells, motors, and power supply units, power density is a crucial consideration. Here, power density often refers to the volume power density, quantifying how much ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cogging Torque
Cogging torque of electrical motors is the torque due to the interaction between the permanent magnet A magnet is a material or object that produces a magnetic field. This magnetic field is invisible but is responsible for the most notable property of a magnet: a force that pulls on other ferromagnetic materials, such as iron, steel, nickel, ...s of the rotor and the stator slots of a permanent magnet machine. It is also known as ''detent'' or ''no-current torque''. This torque is position dependent and its periodicity per revolution depends on the number of magnetic poles and the number of teeth on the stator. Cogging torque is an undesirable component for the operation of such a motor. It is especially prominent at lower speeds, with the symptom of jerkiness. Cogging torque results in torque as well as speed ripple; however, at high speed the motor moment of inertia filters out the effect of cogging torque. Reducing the cogging torque A summary of techniques used for red ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Squirrel-cage Rotor
A squirrel-cage rotor is the rotating part of the common squirrel-cage induction motor. It consists of a cylinder of steel laminations, with aluminum or copper conductors cast in its surface. In operation, the non-rotating stator winding is connected to an alternating current power source; the alternating current in the stator produces a rotating magnetic field. The rotor winding has current induced in it by the stator field, as happens in a transformer, except that the current in the rotor is varying at the stator field rotation rate minus the physical rotation rate. The interaction of the magnetic fields in the stator and the currents in the rotor produce a torque on the rotor. By adjusting the shape of the bars in the rotor, the speed-torque characteristics of the motor can be changed, to minimize starting current or to maximize low-speed torque, for example. Squirrel-cage induction motors are very prevalent in industry, in sizes from below up to tens of megawatts (te ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Electrotechnical Commission
The International Electrotechnical Commission (IEC; ) is an international standards organization that prepares and publishes international standards for all electrical, electronics, electronic and related technologies. IEC standards cover a vast range of technologies from power generation, transmission and distribution to home appliances and office equipment, semiconductors, fibre optics, batteries, solar energy, nanotechnology, and marine energy, as well as many others. The IEC also manages four global conformity assessment systems that certify whether equipment, system or components conform to its international standards. All electrotechnologies are covered by IEC Standards, including energy production and distribution, electronics, magnetics and electromagnetics, electroacoustics, multimedia, telecommunications and medical technology, as well as associated general disciplines such as terminology and symbols, electromagnetic compatibility, measurement and performance, dependa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HarperCollins
HarperCollins Publishers LLC is a British–American publishing company that is considered to be one of the "Big Five (publishers), Big Five" English-language publishers, along with Penguin Random House, Hachette Book Group USA, Hachette, Macmillan Publishers, Macmillan, and Simon & Schuster. HarperCollins is headquartered in New York City and London and is a subsidiary of News Corp. The company's name is derived from a combination of the firm's predecessors. Harper & Brothers, founded in 1817 in New York, merged with Row, Peterson & Company in 1962 to form Harper & Row, which was acquired by News Corp in 1987. The Scotland, Scottish publishing company William Collins, Sons, founded in 1819 in Glasgow, was acquired by News Corp in 1987 and merged with Harper & Row to form HarperCollins. The logo for the firm combines the fire from Harper's torch and the water from Collins' fountain. HarperCollins operates publishing groups in the United States, Canada, the United Kingdom, Austr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rotor For Dual Rotor Motor
ROTOR was an elaborate air defence radar system built by the British Government in the early 1950s to counter possible attack by Soviet bombers. To get it operational as quickly as possible, it was initially made up primarily of WWII-era systems, notably the original Chain Home radars for the early warning role, and the AMES Type 7 for plotting and interception control. Data from these stations was sent to a network of control stations, mostly built underground, using an extensive telephone and telex network. A similar expedient system in the United States was the Lashup Radar Network. ROTOR called for the continual upgrading of the network over time, both the radars and the command and control systems. Among these upgrades was a new microwave frequency radar to replace Chain Home . An experimental system, Green Garlic, was so successful that it began replacing Chain Home starting in 1954. In service, these proved so accurate that they could replace the Type 7 radars as well, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wisconsin Alumni Research Foundation
The Wisconsin Alumni Research Foundation is the independent nonprofit technology transfer organization serving the University of Wisconsin–Madison and Morgridge Institute for Research. It provides significant research support, granting tens of millions of dollars to the university each year and contributing to the university's "margin of excellence". History WARF was founded in 1925 to manage a discovery by Harry Steenbock, who invented the process for using ultraviolet radiation to add vitamin D to milk and other foods. Rather than leaving the invention unpatented—then the standard practice for university inventions—Steenbock used $300 of his own money to file for a patent. He received commercial interest from Quaker Oats but declined the company's initial offer. Instead, Steenbock sought a way to protect discoveries made by UW-Madison faculty, ensure use of the ideas for public benefit and bring any financial gains back to the university. His concept gained supp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Axial Flux Motor
An axial flux motor (axial gap motor, or pancake motor) is a geometry of electric motor construction where the gap between the rotor and stator, and therefore the direction of magnetic flux between the two, is aligned parallel with the axis of rotation, rather than radially as with the concentric cylindrical geometry of the more common radial flux motor. With axial flux geometry torque increases with the cube of the rotor diameter, whereas in a radial flux the increase is only quadratic. Axial flux motors have a larger magnetic surface and overall surface area (for cooling) than radial flux motors for a given volume. Characteristics Advantages * A motor can be built upon any flat structure, such as a PCB, by adding coils and a bearing. * The coil winding process and the process of joining the coil and core may be simpler. * Since the coils are flat, rectangular copper strips can more easily be used, simplifying high-current windings. * It is often possible to make the rotor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radial Flux Motor
A radial flux motor generates flux perpendicular to the axis of rotation. By contrast, an axial flux motor generates flux parallel to the axis. Design The features of a radial flux motor are placed on the sides. The copper windings are wrapped around slots. A traditional radial flux BLDC motor places a rotor made of permanent magnets inside the stator. The stator contains support known as a yoke, which is outfitted with "teeth", individually wrapped with electromagnetic coils. The teeth function as alternating magnetic poles. The rotor’s magnetic poles interact with the alternating magnetic flux of the teeth, producing torque. The use of grain-oriented steel in radial flux motors is challenging due to the curving geometry of the magnetic flux path. Permanent magnet motors Radial flux motors typically use less permanent magnet material, at the cost of lower torque density. Torque, speed, power Torque, speed, and power are related by: P = T * \omega where P is mecha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
