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Topic: Polyphase system

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In the News (Fri 19 Apr 19)

  Polyphase coil - Wikipedia, the free encyclopedia
Polyphase coils are electrical coils (phases) connected together in a polyphase system such as a generator or motor.
In modern systems the number of phases is usually three, or a multiple of three.
Like all coils used in electrical machinery, polyphase coils (made from insulated conducting wire) are wound around ferromagnetic armatures with radial projections and maximum core-surface exposure to the magnetic field.
en.wikipedia.org /wiki/Polyphase_coil   (211 words)

 Polyphase system - Encyclopedia, History and Biography
Polyphase electrical systems supply alternating current electrical power in overlapping phases.
Such systems are sometimes referred to as split phase and are sometimes incorrectly referred to as two phase.
Polyphase power is particularly useful in AC motors, particularly the induction motor, where it generates a rotating magnetic field.
www.arikah.net /encyclopedia/Polyphase_system   (434 words)

 Polyphase system - Wikipedia, the free encyclopedia
A polyphase system must provide a defined direction of phase rotation, so mirror image voltages do not count towards the phase order.
Polyphase power is particularly useful in AC motors, such as the induction motor, where it generates a rotating magnetic field.
A common practice for rectifier installations and in HVDC converters is to provide six phases, with 60 degree phase spacing, to reduce harmonic generation in the ac supply system and to provide smoother direct current.
www.wikipedia.org /wiki/Polyphase_system   (520 words)

 Polyphase hydraulic drive system - US Patent 6837141   (Site not responding. Last check: 2007-10-07)
The hydraulic drive system of claim 14 in which the first cam element is a cam ring and is mounted on a first load-bearing axle and the second cam element is a cam ring and is mounted on a second load-bearing axle.
A control system adjusts the profile of the cam ring to control the transmission ratio, and a pressure compensator automatically reduces the transmission ratio when the resistance torque on the output shaft exceeds a predetermined value, as when the vehicle is ascending a steep hill.
Thus the hydraulic drive system of the present invention may be used for the gear-less and valve-less interconversion of rotational energy, for the conversion of rotational energy to linear kinetic energy, and for the conversion of linear kinetic energy to rotational energy.
www.patentstorm.us /patents/6837141.html   (2862 words)

 Polyphase system -- Facts, Info, and Encyclopedia article   (Site not responding. Last check: 2007-10-07)
Polyphase electrical systems supply (An electric current that reverses direction sinusoidally) alternating current (The product of voltage and current) electrical power in overlapping (Any distinct time period in a sequence of events) phases.
Such systems are sometimes referred to as (Click link for more info and facts about split phase) split phase and are sometimes incorrectly referred to as two phase.
Polyphase power is particularly useful in (An electric current that reverses direction sinusoidally) AC motors, particularly the (Click link for more info and facts about induction motor) induction motor, where it generates a rotating (The lines of force surrounding a permanent magnet or a moving charged particle) magnetic field.
www.absoluteastronomy.com /encyclopedia/p/po/polyphase_system.htm   (580 words)

 Polyphase system
Polyphase electrical systems supply electrical power in overlapping phases, the most common example being three phase power.
In a polyphase system several such supplies are overlapped out of phase to smooth out the total voltage.
In these systems the total power supplied is over 90% of the rated voltage, which is useful for driving high-power motors.
www.ebroadcast.com.au /lookup/encyclopedia/po/Polyphase_system.html   (196 words)

 Learn more about Nikola Tesla in the online encyclopedia.   (Site not responding. Last check: 2007-10-07)
Tesla's most famous contribution was the theory of polyphase alternating current electricity, which he used to build the first induction motor, invented in 1882, as well as developing the designs of numerous other electrical machines and related technology.
The exhibits included a switchboard, polyphase generators, step-up and step-down transformers, transmission line, commercial size induction motors, commercial size synchronous motors, and rotary direct current converters (one of which was operating a railway motor).
A system for "Projecting Concentrated Non-Dispersive Energy Through Natural Media" known as teleforce was reportedly developed later in his life [commonly known as a "death ray" or "peace ray"] (primarily a defensive weapon, with characteristics of a weapon of offense).
www.onlineencyclopedia.org /n/ni/nikola_tesla.html   (5775 words)

 Polyphase system
A polyphase coil takes advantage of the three phase's energy is made up of: induction, neutralization, and capacitance.
Polyphase power is particularly useful in AC motors, where it can be used to generate a rotating magnetic field.
Polyphase electrical systems operate on the principle of a alternate-current circuits' rotating magnetic field lead-lag effect.
www.ukpedia.com /p/polyphase-system.html   (268 words)

 Class 363: ELECTRIC POWER CONVERSION SYSTEMS / U.S. Patent Classification Definitions
Systems which are designed to control a local source of energy by means of a control wave so as to produce an output which is either an enlarged, diminished or identical copy of the control wave of the type used in communication systems are classified as amplifiers in Class 330.
Systems designed to produce an output alternating current of a frequency (f[subscrpt]1[end subscrpt]), from an alternating current having a frequency (f[subscrpt]2[end subscrpt]) may be used as frequency multipliers or frequency dividers.
subclasses 56+ 131+ and 135, for semiconductor inverter systems.
www.uspto.gov /go/taf/def/363.htm   (11819 words)

 Encyclopedia: Polyphase system   (Site not responding. Last check: 2007-10-07)
Visualization of the rotating magnetic field led Nikola Tesla to invent the first practical induction motors - previously all commercial motors were DC, with expensive commutators, high-maintenance brushes, and characteristics unsuitable for operation on an alternating current network.
HVDC or high-voltage, direct current electric power transmission systems contrast with the more common alternating-current systems as a means for the bulk transmission of electrical power.
Residences and small businesses are usually supplied with a single phase taken from one of the three utility phases.
www.nationmaster.com /encyclopedia/Polyphase-system   (1006 words)

 "A New System of Alternate Current Motors and Transformers" by Nikola Tesla   (Site not responding. Last check: 2007-10-07)
The transformers, with their numerous advantages, have afforded us a relatively perfect system of distribution, and although, as in all branches of the art, many improvements are desirable, comparatively little remains to be done in this direction.
In closed circuit armatures, such as used in the continuous current systems, it is best to make four derivations from equi-distant points or bars of the commutator, and to connect the same to four insulated sliding rings on the shaft.
The employment of multipolar motors secures in this system an advantage much desired and unattainable in the continuous current system, and that is, that a motor may be made to run exactly at a predetermined speed irrespective of imperfections in construction, of the load, and, within certain limits, of electromotive force and current strength.
www.tfcbooks.com /tesla/system.htm   (4202 words)

 Single-phase power systems - Chapter 10: POLYPHASE AC CIRCUITS - Volume II - AC   (Site not responding. Last check: 2007-10-07)
This is why power distribution system designers elect to transmit electric power using very high voltages (many thousands of volts): to capitalize on the savings realized by the use of smaller, lighter, cheaper wire.
High voltage gives greater system efficiency by means of reduced conductor current, but it might not always be practical to keep power wiring out of reach at the point of use the way it can be elevated out of reach in distribution systems.
This tradeoff between efficiency and danger is one that European power system designers have decided to risk, all their households and appliances operating at a nominal voltage of 240 volts instead of 120 volts as it is in North America.
www.allaboutcircuits.com /vol_2/chpt_10/1.html   (1669 words)

 Carrier regeneration circuit for polyphase modulation system - Patent 4255713
Polyphase PSK (phase shift keying) systems are presently in use.
Recently, polyphase multiple-valued modulation systems have been investigated in which modulation is effected simultaneously in phase and in amplitude in order to utilize more efficiently the available bandwidth.
Such polyphase multiple-valued modulation systems as previously developed nonetheless have retained some difficulties in circuit construction although they have enabled transmission of an increased amount of information.
www.freepatentsonline.com /4255713.html   (4460 words)

 Chapter 3
Polyphase representation is, in simple terms, a method of re-organizing the coefficients of a given transfer function, h(n).
Polyphase analysis and synthesis: (a) the direct polyphase implementation of an analysis filter and decimator, (b) the same implementation after invoking the noble identities, (c) the polyphase implementation of an expander and synthesis filter, and (d) the same implementation after invoking the noble identities (adapted from Vaidyanathan, 1993a).
The polyphase matrix representation of a two-channel (a) analysis bank and (b) synthesis bank and (c) the polyphase system after simplification.
www.music.miami.edu /programs/mue/research/jvandekieft/jvchapter3.htm   (2442 words)

 Electricity - Encyclopedia.WorldSearch   (Site not responding. Last check: 2007-10-07)
Nikola Tesla performed experiments with very high voltages that are the stuff of legend, involving ball lightning and other effects (some have been duplicated or explained; and others which have not).
Nikola Tesla, inventor of the induction motor and developer of polyphase systems, contributed to the world of electrodynamics the theory of polyphase alternating current, which he used to build the first induction motor, invented in 1882.
This led to a contest in the so-called court of public opinion as to which system would be adopted as the standard for power transmission (known as the War of Currents), Edison's direct-current system or Westinghouse's alternating-current method.
encyclopedia.worldsearch.com /electricity.htm   (1795 words)

 Polyphase stator system for a linear motor - Patent 4360748
The combination as in claim 1 or 2, the means for tying including clamps for clamping the wires to the cables.
Linear motors are well known generally and for a considerable length of time; also, linear motors have been constructed in a variety of configurations; there exist d.c.
The shield's system may actually function as a kind of eddy current brake.
www.freepatentsonline.com /4360748.html   (2143 words)

 Three-phase power systems - Chapter 10: POLYPHASE AC CIRCUITS - Volume II - AC   (Site not responding. Last check: 2007-10-07)
Split-phase power systems achieve their high conductor efficiency and low safety risk by splitting up the total voltage into lesser parts and powering multiple loads at those lesser voltages, while drawing currents at levels typical of a full-voltage system.
Such systems are usually referred to as three-wire systems rather than split-phase because "phase" is a concept restricted to AC.
This principle, applied to power systems, can be put to use to make power systems with even greater conductor efficiencies and lower shock hazard than with split-phase.
www.allaboutcircuits.com /vol_2/chpt_10/2.html   (1682 words)

 Tesla bust
Well, the man who invented the system of polyphase alternating current (AC) power generation and transmission that is used throughout the world today.
Tesla obtained the first U.S. patents in the field of polyphase AC motors (known as induction motors) and power transmission, comprising a complete system of generators, transformers, transmission lines, motors and lighting.
But advance 73 years -- after Tesla's polyphase system was used at Niagara Falls and took electric power to Buffalo and New York City -- to 1969, and that was the year man walked on the moon.
www.news.cornell.edu /Chronicle/04/5.27.04/Tesla_bust.html   (647 words)

 Nikola Tesla Museum - Fifth room   (Site not responding. Last check: 2007-10-07)
In 1893, at the Chicago World Exhibition, Tesla exhibited his ingenious model of the induction motor in which the rotor was a freely rotating metal egg.
Tesla participated with his patents in the contruction of the first big generators for poluphase current, as testified by the plate from one of the generators of the Niagara Plant (1889), placed by the model of hydroenergetic system.
The date of putting into operation the first engines in this Plant is the actual beginning of the hydroenergetic system with a three-phase alternating currents, exhibited in this room, show all the essential elements of Tesla's invention.
www.yurope.com /org/tesla/5e.htm   (297 words)

 TESLAco and Nikola Tesla   (Site not responding. Last check: 2007-10-07)
Today, that system is still unsurpassed in its efficient and economic generation, transmission, and usage of virtually all available electrical power, and is the single most important factor in the widespread use of electrical energy as we know it now.
To make the transmitted polyphase currents perform mechanical work, he invented a revolutionary polyphase AC motor, which is by far superior to the conventional Direct Current (DC) commutator motor.
In the days of the Wars of Currents, Tesla fought for his new AC power system and AC motor against Edison, who was backing DC power generation and transmission and DC motors.
www.teslaco.com /tesla.htm   (395 words)

 Nikola Tesla: Chicago World's Fair   (Site not responding. Last check: 2007-10-07)
The exhibit, then, contained a polyphase generator with transformers for raising the voltage for transmission; a short transmission line; transformers for lowering the voltage; the operation of induction motors; a synchronous motor; and a rotary converter which supplied direct current, which in turn operated a railway motor.
The apparatus was in units of fair commercial size and gave to the public a view of a universal power system in which, by polyphase current, power could be transmitted great distances, and then be utilized for various purposes, including the supply of direct current.
It showed on a working scale a system upon which Westinghouse and his company had been concentrating their efforts; namely, the alternating-current and polyphase system.
www.neuronet.pitt.edu /~bogdan/tesla/chicago.htm   (354 words)

 Polyphase System Encyclopedia Article, Definition, History, Biography   (Site not responding. Last check: 2007-10-07)
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www.karr.net /search/encyclopedia/Polyphase_system   (665 words)

 Lessons In Electric Circuits -- Volume II (AC) - Chapter 10
Polyphase motors don't need such measures; their direction of rotation is fixed by the phase sequence of the voltage they're powered by.
With a Y-connected system, a neutral wire was needed in case one of the phase loads were to fail open (or be turned off), in order to keep the phase voltages at the load from changing.
Since the higher-order harmonics tend to be attenuated more by system inductances and magnetic core losses, and generally originate with less amplitude anyway, the primary harmonic of concern is the 5th, which is 300 Hz in 60 Hz power systems and 250 Hz in 50 Hz power systems.
www.ibiblio.org /obp/electricCircuits/AC/AC_10.html   (10904 words)

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