| 单词 | field magnet |
| 例句 | In the first case the current through the field-helices will be partly neutralized and the magnetism of the field magnets will be diminished. The inventions, researches and writings of Nikola Tesla With special reference to his work in polyphase currents and high potential lighting 2012-03-28T02:00:22.660Z In this year he constructed an electric motor having its field magnets as well as its armature excited by the electric current. Inventors 2012-02-08T03:00:16.647Z A characteristic feature is that in the dynamo the field magnet is the stationary part and the armature the rotating part, while in the alternator the reverse conditions usually obtain. Hawkins Electrical Guide, Number One Questions, Answers, & Illustrations, A Progressive Course of Study for Engineers, Electricians, Students and Those Desiring to acquire a Working Knowledge of Electricity and its Applications 2011-12-24T03:07:54.823Z Magneto field magnets are always made of tungsten steel alloy, so treated that it will retain its magnetism for lengthy periods. Aviation Engines Design?Construction?Operation and Repair 2011-12-04T03:00:04.777Z Series Motor.—In this type the field magnet windings are connected in series with the armature winding, i.e. the same current flows in both windings. The New Gresham Encyclopedia Volume 4, Part 2: Ebert to Estremadura 2011-04-14T02:00:56.200Z The field magnets and frame are cast in two parts. The inventions, researches and writings of Nikola Tesla With special reference to his work in polyphase currents and high potential lighting 2012-03-28T02:00:22.660Z Siemens effected a great improvement by inventing a shuttle armature and improving the shape of the field magnet. Encyclopaedia Britannica, 11th Edition, Volume 9, Slice 2 "Ehud" to "Electroscope" 2011-01-29T03:00:23.777Z What is the real distinction between an armature and a field magnet? Hawkins Electrical Guide, Number One Questions, Answers, & Illustrations, A Progressive Course of Study for Engineers, Electricians, Students and Those Desiring to acquire a Working Knowledge of Electricity and its Applications 2011-12-24T03:07:54.823Z Holmes continuous current dynamo: A, armature; C, commutator; M, field magnets. How it Works Dealing in simple language with steam, electricity, light, heat, sound, hydraulics, optics, etc., and with their applications to apparatus in common use In actual practice, field magnets of dynamos are worked at densities up to and over 100,000 lines of force to the square inch, and armatures contain several hundred conductors to "cut" these magnetic lines. Electricity for the farm Light, heat and power by inexpensive methods from the water wheel or farm engine In other words, the eddy currents circulating in the disc will energize the field magnet. The inventions, researches and writings of Nikola Tesla With special reference to his work in polyphase currents and high potential lighting 2012-03-28T02:00:22.660Z This is generally the case in the electromagnets which are employed as the field magnets in dynamo machines. Encyclopaedia Britannica, 11th Edition, Volume 9, Slice 2 "Ehud" to "Electroscope" 2011-01-29T03:00:23.777Z What important advantage is gained by the use of multi-pole field magnets? Hawkins Electrical Guide, Number One Questions, Answers, & Illustrations, A Progressive Course of Study for Engineers, Electricians, Students and Those Desiring to acquire a Working Knowledge of Electricity and its Applications 2011-12-24T03:07:54.823Z Until current passes through the field magnet coils, no magnetic field can be created. How it Works Dealing in simple language with steam, electricity, light, heat, sound, hydraulics, optics, etc., and with their applications to apparatus in common use As the resistance of the external circuit is lowered, by turning on more and more lights, more and more current flows from the armature, through the field magnets. Electricity for the farm Light, heat and power by inexpensive methods from the water wheel or farm engine The field magnet consists of a ring of wrought iron with 384 pole projections. The inventions, researches and writings of Nikola Tesla With special reference to his work in polyphase currents and high potential lighting 2012-03-28T02:00:22.660Z Further progress was made in 1867 when H. Wilde introduced the use of electromagnets for the field magnets. Encyclopaedia Britannica, 11th Edition, Volume 9, Slice 2 "Ehud" to "Electroscope" 2011-01-29T03:00:23.777Z The former has its field magnets F F magnetized by means of a small current flowing around a shunt circuit. Hawkins Electrical Guide, Number One Questions, Answers, & Illustrations, A Progressive Course of Study for Engineers, Electricians, Students and Those Desiring to acquire a Working Knowledge of Electricity and its Applications 2011-12-24T03:07:54.823Z These have their field magnets excited by a separate continuous current dynamo of small size. How it Works Dealing in simple language with steam, electricity, light, heat, sound, hydraulics, optics, etc., and with their applications to apparatus in common use Each time the resistance is lowered, therefore, the current passing through the field magnets becomes more dense in amperes, and makes the field magnets correspondingly stronger. Electricity for the farm Light, heat and power by inexpensive methods from the water wheel or farm engine The field magnet of this machine consists of two like parts which either enclose an exciting coil, or else are independently wound. The inventions, researches and writings of Nikola Tesla With special reference to his work in polyphase currents and high potential lighting 2012-03-28T02:00:22.660Z An apparatus, consisting of core and field magnets, which, when the core is turned, will develop a current of electricity. Electricity for Boys Part or all of the current induced in the armature is passed through the windings of the field magnets, thus strengthening the field. Hawkins Electrical Guide, Number One Questions, Answers, & Illustrations, A Progressive Course of Study for Engineers, Electricians, Students and Those Desiring to acquire a Working Knowledge of Electricity and its Applications 2011-12-24T03:07:54.823Z The field magnets constitute the periphery of the revolving field, the poles and rim of the field being built up by steel plates which are dovetailed to the driving spider. The New York Subway Its Construction and Equipment By separately exciting the field magnets from another dynamo, and observing the increased steam pressure required to maintain the speed constant, the corresponding power was afterward calculated in watts. Scientific American Supplement, No. 633, February 18, 1888 The armature consists of a wheel of hard bronze, carrying the conductors which revolve between the projections of the field magnet. The inventions, researches and writings of Nikola Tesla With special reference to his work in polyphase currents and high potential lighting 2012-03-28T02:00:22.660Z Let us assume that the field magnets A, A are the positives,p. Electricity for Boys In this machine, the field magnets are wound with a few turns of thick wire joined in series with the armature brushes as shown in fig. Hawkins Electrical Guide, Number One Questions, Answers, & Illustrations, A Progressive Course of Study for Engineers, Electricians, Students and Those Desiring to acquire a Working Knowledge of Electricity and its Applications 2011-12-24T03:07:54.823Z The two standards, supporting the cylinder and forming the guide bars, together with the entire field magnets and pole pieces of the dynamo, and the bed plate common to both, are cast in one piece. Scientific American Supplement, No. 711, August 17, 1889 The magnetic strength of the field magnet influences greatly the speed of the armature; the stronger the field magnet the greater the motion, so electricians make every effort to strengthen their field magnets. General Science For this purpose it is best to employ a motor consisting of a stationary field magnet and an armature arranged to rotate within the same, as indicated in Fig. The inventions, researches and writings of Nikola Tesla With special reference to his work in polyphase currents and high potential lighting 2012-03-28T02:00:22.660Z In the circuit of the field magnet is placed a variable resistance. Scientific American Supplement, No. 623, December 10, 1887 The current in passing through the field magnets, energizes them and strengthens the weak field due to the residual magnetism of the magnet cores, resulting in the gradual building up of the field. Hawkins Electrical Guide, Number One Questions, Answers, & Illustrations, A Progressive Course of Study for Engineers, Electricians, Students and Those Desiring to acquire a Working Knowledge of Electricity and its Applications 2011-12-24T03:07:54.823Z The field magnets, which surround the armature, are cast iron shells, wound outside with many convolutions of insulated copper wire, and are joined externally by iron bars to convey the magnetism. Scientific American Supplement, No. 388, June 9, 1883 But no matter how complex these various parts may seem to be, the principle is always that stated in Section 309, and the parts are limited to field magnet, commutator, and armature. General Science Without any load the speed is very nearly equal to that of the shifting poles of the field magnet. The inventions, researches and writings of Nikola Tesla With special reference to his work in polyphase currents and high potential lighting 2012-03-28T02:00:22.660Z Another device, patented by Mr. Crompton, is a modification of that method of field magnet winding commonly known as compound winding. Scientific American Supplement, No. 623, December 10, 1887 The coils of the field magnet form a shunt to the main circuit; they consist of many turns of fine wire and consequently absorb only a small fraction of the current induced in the armature. Hawkins Electrical Guide, Number One Questions, Answers, & Illustrations, A Progressive Course of Study for Engineers, Electricians, Students and Those Desiring to acquire a Working Knowledge of Electricity and its Applications 2011-12-24T03:07:54.823Z The field magnets are of the horizontal double type. Scientific American Supplement No. 822, October 3, 1891 The rotating coil is usually spoken of as the armature, and the large magnet as the field magnet. General Science He employs a motor with two sets of energizing or field magnets, each wound with coils connected with a source of alternating or rapidly-varying currents, but forming two separate paths or circuits. The inventions, researches and writings of Nikola Tesla With special reference to his work in polyphase currents and high potential lighting 2012-03-28T02:00:22.660Z That is to say, the current in the shunt wire tends to magnetize the iron of the field magnets in an opposite direction to that of the series wire. Scientific American Supplement, No. 623, December 10, 1887 The Shunt Dynamo.—The shunt wound dynamo differs from the series wound machine, in that an independent circuit is used for exciting its field magnet. Hawkins Electrical Guide, Number One Questions, Answers, & Illustrations, A Progressive Course of Study for Engineers, Electricians, Students and Those Desiring to acquire a Working Knowledge of Electricity and its Applications 2011-12-24T03:07:54.823Z While a motor of this kind is, in conjunction with such a switch, the most efficient, the motor with permanent field magnets is preferable as regards cost and ease of fixing. Things To Make For this reason, the field magnet is usually an electromagnet. General Science Then the iron is weakly but permanently attracted, showing that synchronism is reached and the field magnet energized by induction. The inventions, researches and writings of Nikola Tesla With special reference to his work in polyphase currents and high potential lighting 2012-03-28T02:00:22.660Z When a condenser is put on a dynamo, the condenser current leads relatively to the electromotive force, and therefore strengthens the field magnets and increases the pressure. Scientific American Supplement, No. 795, March 28, 1891 The field magnets of the compound dynamo, as shown in fig. Hawkins Electrical Guide, Number One Questions, Answers, & Illustrations, A Progressive Course of Study for Engineers, Electricians, Students and Those Desiring to acquire a Working Knowledge of Electricity and its Applications 2011-12-24T03:07:54.823Z Only here we must have just a little residual magnetism in the field magnet to start the whole process. A Librarian's Open Shelf The generating machine is driven by a locomotive engine; the resistance of its field magnets is 5.68 ohms, and of the two armatures 33 ohms. Scientific American Supplement, No. 520, December 19, 1885 The field magnet was made relatively small so as to adapt the machine for a constant current. The inventions, researches and writings of Nikola Tesla With special reference to his work in polyphase currents and high potential lighting 2012-03-28T02:00:22.660Z As regards Mr. Mordey's observation, he thought the action explicable on the theory of the leading condenser current acting on the field magnets. Scientific American Supplement, No. 795, March 28, 1891 The compound dynamo is a combination of the series and shunt types, that is, the field magnet is excited by both series and shunt windings. Hawkins Electrical Guide, Number One Questions, Answers, & Illustrations, A Progressive Course of Study for Engineers, Electricians, Students and Those Desiring to acquire a Working Knowledge of Electricity and its Applications 2011-12-24T03:07:54.823Z We had no means of boring out the field magnets, and we cut grooves in them. Edison, His Life and Inventions The resistance of the two armatures of the receiving machine is 36.8 ohms, and the resistance of the line is 97 ohms; the generator and receiver field magnets are excited each by a separate machine. Scientific American Supplement, No. 520, December 19, 1885 An armature core constructed in the manner described may be revolved between the poles of the field magnets without showing the slightest increase of temperature. The inventions, researches and writings of Nikola Tesla With special reference to his work in polyphase currents and high potential lighting 2012-03-28T02:00:22.660Z When transformers are used, the field magnets are weak, while the condenser current rises to 40 amperes. Scientific American Supplement, No. 795, March 28, 1891 Separately Excited Dynamos.—In this class of machine the current required to excite the field magnets is obtained from some independent external source. Hawkins Electrical Guide, Number One Questions, Answers, & Illustrations, A Progressive Course of Study for Engineers, Electricians, Students and Those Desiring to acquire a Working Knowledge of Electricity and its Applications 2011-12-24T03:07:54.823Z The blow broke the glass carboy, and the acid ran down upon the field magnets of the dynamo, destroying the windings of one of the twelve magnets. Edison, His Life and Inventions The field magnets are also wound in a similar manner. Scientific American Supplement, No. 392, July 7, 1883 If the disc be rotated and the field current interrupted, the current through the armature will continue to flow and the field magnets will lose their strength comparatively slowly. The inventions, researches and writings of Nikola Tesla With special reference to his work in polyphase currents and high potential lighting 2012-03-28T02:00:22.660Z The armature, for instance, must not give way to the centrifugal forces imposed upon it, nor should the field magnets be so flexible as to yield to the statical pull of the magnetic poles. Scientific American Supplement, No. 430, March 29, 1884 The object of the field magnet is to produce an intense magnetic field within which the armature revolves. Hawkins Electrical Guide, Number One Questions, Answers, & Illustrations, A Progressive Course of Study for Engineers, Electricians, Students and Those Desiring to acquire a Working Knowledge of Electricity and its Applications 2011-12-24T03:07:54.823Z In the field magnets of his dynamo he constructed the cores and yoke of forged iron having a very large cross-section, which was a new thing in those days. Edison, His Life and Inventions The field magnets are made in a similar manner to the armature and run in circles parallel to the rim of the latter. Scientific American Supplement, No. 392, July 7, 1883 In this arrangement the current flowing through the disc and external circuit will have no appreciable effect on the field magnet. The inventions, researches and writings of Nikola Tesla With special reference to his work in polyphase currents and high potential lighting 2012-03-28T02:00:22.660Z This lowers the resistance and the field magnets of the dynamo are made stronger so that additional voltage is provided to care for the resistance in the metal being heated. Oxy-Acetylene Welding and Cutting Electric, Forge and Thermit Welding together with related methods and materials used in metal working and the oxygen process for removal of carbon The field magnet, in addition to furnishing the magnetic field, has to do duty as a framework which often involves considerations other than those respecting maximum economy. Hawkins Electrical Guide, Number One Questions, Answers, & Illustrations, A Progressive Course of Study for Engineers, Electricians, Students and Those Desiring to acquire a Working Knowledge of Electricity and its Applications 2011-12-24T03:07:54.823Z A difference in the arrangement of the terminals of the wire coils or the wrappings of armature and field magnet, makes of the one a dynamo and of the other a motor. Steam, Steel and Electricity In the "series-wound" machine the whole of the current generated in the armature also goes through the coils of the field magnets. The Story of Electricity When it is desired to rotate the conductor between the faces of a stationary field magnet, the construction shown in Fig. The inventions, researches and writings of Nikola Tesla With special reference to his work in polyphase currents and high potential lighting 2012-03-28T02:00:22.660Z What is the object of the field magnet? Hawkins Electrical Guide, Number One Questions, Answers, & Illustrations, A Progressive Course of Study for Engineers, Electricians, Students and Those Desiring to acquire a Working Knowledge of Electricity and its Applications 2011-12-24T03:07:54.823Z What materials are generally used for field magnets? Hawkins Electrical Guide, Number One Questions, Answers, & Illustrations, A Progressive Course of Study for Engineers, Electricians, Students and Those Desiring to acquire a Working Knowledge of Electricity and its Applications 2011-12-24T03:07:54.823Z In like manner, the huge field magnets of a modern dynamo are not whirled round a stationary armature, but the armature is whirled within the legs of the magnet with very great rapidity. Steam, Steel and Electricity The current of the series machine varies with the resistance of the external or working circuit, because that is included in the circuit of the field magnets and the armature. The Story of Electricity In this class of machine, the armature and field magnets are surrounded by a circular frame, or ring yoke to which the field magnets are attached. Hawkins Electrical Guide, Number One Questions, Answers, & Illustrations, A Progressive Course of Study for Engineers, Electricians, Students and Those Desiring to acquire a Working Knowledge of Electricity and its Applications 2011-12-24T03:07:54.823Z In a magneto the field magnets are permanently magnetized. Hawkins Electrical Guide, Number One Questions, Answers, & Illustrations, A Progressive Course of Study for Engineers, Electricians, Students and Those Desiring to acquire a Working Knowledge of Electricity and its Applications 2011-12-24T03:07:54.823Z That is, without residual magnetism in the field magnet core, the dynamo when started would not generate any current unless it received an initial excitation from an external source. Hawkins Electrical Guide, Number One Questions, Answers, & Illustrations, A Progressive Course of Study for Engineers, Electricians, Students and Those Desiring to acquire a Working Knowledge of Electricity and its Applications 2011-12-24T03:07:54.823Z This weak current, passing through the windings of the field magnet, makes these still stronger magnets, and the effect is to evolve a still stronger current in the armature. Steam, Steel and Electricity In the "shunt-wound" machine the field magnets are excited by diverting a small portion of the main current from the armature through them, by means of a "shunt" or loop circuit. The Story of Electricity The coils of the field magnet are in series with those of the armature and external circuit, and consists of a few turns of heavy wire. Hawkins Electrical Guide, Number One Questions, Answers, & Illustrations, A Progressive Course of Study for Engineers, Electricians, Students and Those Desiring to acquire a Working Knowledge of Electricity and its Applications 2011-12-24T03:07:54.823Z The maximum voltage will depend upon the capacity of the field magnets as determined by the construction, and upon the strength of current used to excite them. Hawkins Electrical Guide, Number One Questions, Answers, & Illustrations, A Progressive Course of Study for Engineers, Electricians, Students and Those Desiring to acquire a Working Knowledge of Electricity and its Applications 2011-12-24T03:07:54.823Z What is the object of the field magnet? Hawkins Electrical Guide, Number One Questions, Answers, & Illustrations, A Progressive Course of Study for Engineers, Electricians, Students and Those Desiring to acquire a Working Knowledge of Electricity and its Applications 2011-12-24T03:07:54.823Z The big iron field magnet, often weighing some thousands of pounds, is then the same as a permanent steel horseshoe magnet, which would hardly be possible at all. Steam, Steel and Electricity All of the current generated by the machine passes through the coils of the field magnets to the external circuit. Hawkins Electrical Guide, Number One Questions, Answers, & Illustrations, A Progressive Course of Study for Engineers, Electricians, Students and Those Desiring to acquire a Working Knowledge of Electricity and its Applications 2011-12-24T03:07:54.823Z Again, a decrease in the resistance of the external circuit will increase the voltage because more current will flow through the field magnets. Hawkins Electrical Guide, Number One Questions, Answers, & Illustrations, A Progressive Course of Study for Engineers, Electricians, Students and Those Desiring to acquire a Working Knowledge of Electricity and its Applications 2011-12-24T03:07:54.823Z Though used by Faraday, the separately excited dynamo did not come into favor until, in 1866, Wilde employed a small auxiliary magneto machine to furnish currents to excite the field magnets of a larger dynamo. Hawkins Electrical Guide, Number One Questions, Answers, & Illustrations, A Progressive Course of Study for Engineers, Electricians, Students and Those Desiring to acquire a Working Knowledge of Electricity and its Applications 2011-12-24T03:07:54.823Z How do armatures and field magnets differ in dynamos and alternators? Hawkins Electrical Guide, Number One Questions, Answers, & Illustrations, A Progressive Course of Study for Engineers, Electricians, Students and Those Desiring to acquire a Working Knowledge of Electricity and its Applications 2011-12-24T03:07:54.823Z He caused the current, after it had been rectified by the commutator, to return again into coils of wire round the legs of his field magnets, as shown in the diagram. Steam, Steel and Electricity Classes of Field Magnet.—Although numerous forms of field magnet have been devised, they can be classed into two groups according to the type of pole, as: 1. Hawkins Electrical Guide, Number One Questions, Answers, & Illustrations, A Progressive Course of Study for Engineers, Electricians, Students and Those Desiring to acquire a Working Knowledge of Electricity and its Applications 2011-12-24T03:07:54.823Z In the construction of field magnets, what governs the choice of materials? Hawkins Electrical Guide, Number One Questions, Answers, & Illustrations, A Progressive Course of Study for Engineers, Electricians, Students and Those Desiring to acquire a Working Knowledge of Electricity and its Applications 2011-12-24T03:07:54.823Z What determines chiefly the cost of field magnets? Hawkins Electrical Guide, Number One Questions, Answers, & Illustrations, A Progressive Course of Study for Engineers, Electricians, Students and Those Desiring to acquire a Working Knowledge of Electricity and its Applications 2011-12-24T03:07:54.823Z With respect to this feature, what names are sometimes given to the armature and field magnet? Hawkins Electrical Guide, Number One Questions, Answers, & Illustrations, A Progressive Course of Study for Engineers, Electricians, Students and Those Desiring to acquire a Working Knowledge of Electricity and its Applications 2011-12-24T03:07:54.823Z Sometimes, to hasten first action, some cells of a galvanic battery are used to pass a current through the coils of the field magnet. Steam, Steel and Electricity Ventilation.—Sometimes provision is made for ventilation of the field magnet coils as shown in fig. Hawkins Electrical Guide, Number One Questions, Answers, & Illustrations, A Progressive Course of Study for Engineers, Electricians, Students and Those Desiring to acquire a Working Knowledge of Electricity and its Applications 2011-12-24T03:07:54.823Z In it the field magnet—answering to the horseshoe magnet of the magneto-electric machine—is plainly distinguishable to the unskilled observer. Steam, Steel and Electricity |
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