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Walter Baily's Motor
Walter Bailys Polyphase motor (1879) marks the beginning of the development of modern polyphase motor, polyphase motors. Mr. Bailey exhibited his invention on the Physical Society of London on June 28, 1879, on the occasion of his reading a paper entitled, "A Mode of Producing Arago's Rotations." Description Before Baily's invention, the only mode of producing the Arago's rotations, Arago-rotations of a copper disk had been by rotating beneath it a steel magnet. Baily, instead of rotating any material magnet below the disk used a fixed electromagnet, but caused its magnetism to shift progressively between four successive poles, thus producing in the copper disk pivoted above the Eddy current, eddy-currents, which by their reaction gave the disk a mechanical motion in the direction of the progression of the poles. The disk in this primitive model is about inches in diameter; the four magnet cores are about 4 inches high, joined to a common yoke; and each is wound with about 150 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyphase Motor
A polyphase system (the term coined by Silvanus Thompson) is a means of distributing alternating-current (AC) electrical power that utilizes more than one AC phase, which refers to the phase offset value (in degrees) between AC in multiple conducting wires; ''phases'' may also refer to the corresponding terminals and conductors, as in color codes. Polyphase systems have two or more energized electrical conductors carrying alternating currents with a defined phase between the voltage waves in each conductor. Early systems used 4 wire two-phase with a 90° phase angle, but modern systems almost universally use three-phase voltage, with a phase angle of 120° (or 2π/3 radians). Polyphase systems are particularly useful for transmitting power to electric motors which rely on alternating current to rotate. Three-phase power is used for industrial applications and for power transmission. Compared to a single-phase, two-wire system, a three-phase three-wire system transmits thr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Commutator (electric)
A commutator is a rotary switch, electrical switch in certain types of electric motors and electrical generators that periodically reverses the Current (electricity), current direction between the rotor and the external circuit. It consists of a cylinder composed of multiple metal contact segments on the rotating armature (electrical engineering), armature of the machine. Two or more electrical contacts called "brush (electric), brushes" made of a soft conductive material like carbon press against the commutator, making sliding contact with successive segments of the commutator as it rotates. The windings (coils of wire) on the armature (electrical engineering), armature are connected to the commutator segments. Commutators are used in direct current (DC) machines: dynamos (DC generators) and many DC motors as well as universal motors. In a motor the commutator applies electric current to the windings. By reversing the current direction in the rotating windings each half turn, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Induction Motor
An induction motor or asynchronous motor is an AC motor, AC electric motor in which the electric current in the rotor (electric), rotor that produces torque is obtained by electromagnetic induction from the magnetic field of the stator winding. An induction motor therefore needs no electrical connections to the rotor. An induction motor's rotor can be either wound rotor motor, wound type or squirrel-cage rotor, squirrel-cage type. Three-phase Squirrel-cage rotor, squirrel-cage induction motors are widely used as industrial drives because they are self-starting, reliable, and economical. Single-phase electric power, Single-phase induction motors are used extensively for smaller loads, such as garbage disposals and stationary power tools. Although traditionally used for constant-speed service, single- and three-phase induction motors are increasingly being installed in variable-speed applications using variable-frequency drives (VFD). VFD offers energy savings opportunities for i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Timeline Of The Electric Motor
Electric motors An electric motor is a machine that converts electrical energy into mechanical energy. Most electric motors operate through the interaction between the motor's magnetic field and electric current in a wire winding to generate Laplace force i ... have a long history, dating back to the early nineteenth century. Nineteenth century Twentieth century References {{electric motor Electric motors ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frederick Guthrie (scientist)
Frederick Guthrie FRS FRSE (15 October 1833 – 21 October 1886) was a British physicist, chemist, and academic author. He was the son of Alexander Guthrie, a London tradesman, and the younger brother of mathematician Francis Guthrie. Along with William Fletcher Barrett he founded the Physical Society of London (now the Institute of Physics) in 1874 and was president of the society from 1884 until 1886. He believed that science should be based on experimentation rather than discussion. Academic career His academic career started at University College, London, where he studied for three years. He studied chemistry under Thomas Graham and Alexander William Williamson and mathematics under Augustus De Morgan. In 1852, he submitted his brother Francis's observations to De Morgan. In 1854 Guthrie went to Heidelberg to study under Robert Bunsen and then in 1855 obtained a PhD at the University of Marburg under Adolph Wilhelm Hermann Kolbe. In 1856 he joined Edward Frankland ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electric Battery
An electric battery is a source of electric power consisting of one or more electrochemical cells with external connections for powering electrical devices. When a battery is supplying power, its positive Terminal (electronics), terminal is the cathode and its negative terminal is the anode. The terminal marked negative is the source of electrons. When a battery is connected to an external electric load, those negatively charged electrons flow through the circuit and reach the positive terminal, thus causing a redox reaction by attracting positively charged ions, or cations. Thus, higher energy reactants are converted to lower energy products, and the Gibbs free energy, free-energy difference is delivered to the external circuit as electrical energy. Historically the term "battery" specifically referred to a device composed of multiple cells; however, the usage has evolved to include devices composed of a single cell. Primary battery, Primary (single-use or "disposable") batter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rotating Magnetic Field
A rotating magnetic field (RMF) is the resultant magnetic field produced by a system of Electromagnetic coil, coils symmetrically placed and supplied with Polyphase system, polyphase currents. A rotating magnetic field can be produced by a poly-phase (two or more phases) current or by a single phase current provided that, in the latter case, two field windings are supplied and are so designed that the two resulting magnetic fields generated thereby are out of phase. Rotating magnetic fields are often utilized for Electromechanics, electromechanical applications, such as induction motors, electric generators and induction regulators. History In 1824, the French physicist François Arago formulated the existence of rotating magnetic fields using a rotating copper disk and a needle, termed “Arago's rotations.” English experimenters Charles Babbage and John Herschel found they could induce rotation in Arago's copper disk by spinning a horseshoe magnet under it, with English scienti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bayley Motor Magnetic Poles
Bayley may refer to: * Bayley (wrestler) Pamela Rose Martinez (born June 15, 1989) is an American professional wrestler. She is signed to WWE, where she performs on the Raw (WWE brand), Raw WWE brand extension, brand under the ring name Bayley. Her 380-day reign as WWE SmackDown Women' ... (born 1989), American professional wrestler * Bayley Cooke (born 1963), English heavy metal singer * Bayley Currey (born 1996), American professional stock car racing driver * Bayley Feist (born 1997), American professional soccer player * Bayley Fritsch (born 1996), Australian rules footballer * Bayley Kuenzle (born 1998), Australian professional rugby union player * Bayley Liu (born 1996), Scotland international rugby league footballer * Bayley Simpson (born 1997), Canadian cyclist * Bayley Sironen (born 1996), Australian professional rugby league footballer * Bayley Wiggins (born 1998), New Zealand cricketer * Bayley (surname) * Bayley House * Bayley Scales of Infant Development ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Horseshoe Magnet
A horseshoe magnet is either a permanent magnet or an electromagnet made in the shape of a horseshoe (in other words, in a U-shape). The permanent kind has become the most widely recognized symbol for magnets. It is usually depicted as red and marked with 'North' and 'South' poles. Although rendered obsolete in the 1950s by squat, cylindrical magnets made of modern materials, horseshoe magnets are still regularly shown in elementary school textbooks. Historically, they were a solution to the problem of making a compact magnet that does not destroy itself in its own demagnetizing field. History In 1819, it was discovered that passing electric current through a piece of metal deflected a compass needle. Following this discovery, many other experiments surrounding magnetism were attempted. These experiments culminated in William Sturgeon wrapping wire around a horseshoe-shaped piece of iron and running electric current through the wires creating the first horseshoe magnet. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Physical Society Of London
The Physical Society of London, England, was a scientific society which was founded in 1874. In 1921, it was renamed the Physical Society, and in 1960 it merged with the Institute of Physics (IOP), the combined organisation eventually adopting the name of the latter society. The society was founded due to the efforts of Frederick Guthrie, Professor of Physics at the Royal College of Science, South Kensington, and his assistant, William Fletcher Barrett. They canvassed support for a 'Society for physical research' and on 14 February 1874, the Physical Society of London was formed with an initial membership of 29 people. The Society's first president was John Hall Gladstone. Meetings were held every two weeks, mainly at Imperial College London. From its beginning, the society held open meetings and demonstrations and published '' Proceedings of the Physical Society of London''. The first Guthrie lecture, now known as the Faraday Medal and Prize, was delivered in 1914. In 1921 t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetism
Magnetism is the class of physical attributes that occur through a magnetic field, which allows objects to attract or repel each other. Because both electric currents and magnetic moments of elementary particles give rise to a magnetic field, magnetism is one of two aspects of electromagnetism. The most familiar effects occur in ferromagnetic materials, which are strongly attracted by magnetic fields and can be magnetized to become permanent magnets, producing magnetic fields themselves. Demagnetizing a magnet is also possible. Only a few substances are ferromagnetic; the most common ones are iron, cobalt, nickel, and their alloys. All substances exhibit some type of magnetism. Magnetic materials are classified according to their bulk susceptibility. Ferromagnetism is responsible for most of the effects of magnetism encountered in everyday life, but there are actually several types of magnetism. Paramagnetic substances, such as aluminium and oxygen, are weakly attracted ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
