| 释义 |
magˌneto-eˈlectric, a.
Pertaining to electric phenomena involving electric currents induced in conductors by the relative motion of these conductors with respect to either permanent magnets or electro-magnets.
Introduced, in 1831, by Faraday, who employed it in its most general sense for describing the currents induced by motion of conduction in conjunction with any of the following kinds of magnet: permanent steel magnets, ordinary loadstones, electro-magnets, the earth. He used it tentatively at first in contradistinction to the term volta-electric, which he applied to the induction of electricity by turning on or turning off an electric current in a stationary coil.
1831Faraday in Phil. Trans. (1832) CXXII. 139 As a distinction in language is still necessary, I propose to call the agency thus exerted by ordinary magnets, magneto-electric or magnelectric induction. Ibid. 173 Upon the supposition that the rotation of the earth tended, by magneto-electric induction, to cause currents in its own mass. 1833Ibid. CXXIII. 44, I had the pleasure..of making an experiment, for which the great magnet [a loadstone] in the museum.. and the magneto-electric coil described in my first paper, were put in requisition. 1834― in Philos. Mag. V. 349 When I first obtained the magneto-electric spark it was by the use of a secondary magnet...My principal was an electromagnet; Nobili's was, I believe, an ordinary magnet; others have used the natural magnet. 1839J. F. Daniell Introd. Chem. Philos. 489 Magneto-electric is the converse to electro-magnetic action. 1854G. Bird & C. Brooke Elem. Nat. Philos. xvii. (ed. 4) 421 note, Similarly, electro-magnetic induction would mean the development of magnetism by a current, and magneto-electric induction, that of a current by magnetism. 1881Maxwell Electr. & Magn. II. 208 This is the electromotive force which must be supplied from sources independent of magneto-electric induction.
b. magneto-electric current. Used by Faraday to distinguish currents generated mechanically by magneto-electric induction from those generated in a voltaic battery.
1851Faraday in Phil. Trans. CXLII. (1852) 137 On the employment of the Induced Magneto-electric Current as a test and measure of Magnetic Forces.
c. magneto-electric machine. First used by Faraday, in 1831, to denote a machine generating currents by magneto-electric induction. By later writers employed in variously limited senses.
The appellation continued to be used in Faraday's wide sense by various writers down to about 1867, when the improvements of Wilde, Wheatstone, Siemens, Ladd, Varley and others attracted much attention, and the term ‘dynamo-electric machine’ was introduced by Brooke. This term was defined by Brooke himself to denote in general a machine ‘in which dynamic energy is employed to produce an electric current’ (Proc. Roy. Soc. XV. 409, footnote); by others, however, it has been applied to signify only such machines as embodied the principle of self-excitation and did not contain any permanent magnets. Those who adopted the latter usage limited the meaning of ‘magneto-electric machine’; some including under that term only the machines with permanent magnets of steel, while others included under the name both these and the machines with separately-excited electro-magnets. The present tendency is to confine the term strictly to the machines with permanent steel magnets. Some writers define magneto-electric machines as simply old-fashioned or rudimentary kinds of dynamos; others treat the terms as synonymous. On the other hand some writers treat ‘magneto-electric machine’ as a generic term, of which dynamo-electric machines form a sub-class.
1831Faraday in Phil. Trans. (1832) CXXII. 160 Two rough trials were made with the intention of constructing magneto-electric machines. Ibid. 163 [Under heading Terrestrial Magneto-electric Induction, describes as magneto-electric machines discs of copper caused to revolve, and thereby generate electric currents under the magnetic influence of the earth.] 1866Crookes in Q. Jrnl. Sci. XII. 504 Magneto-electric machines, with revolving armatures, in which electro-magnets had been substituted for permanent magnets, had been constructed. 1867Wheatstone in Proc. Roy. Soc. XV. 369 The magneto-electric machines which have been hitherto described are actuated either by a permanent magnet or by an electro-magnet. 1878Proc. Inst. Civ. Engin. LII. 63 M. Alfred Niaudet remarked that he did not agree with..the distinction between dynamo-electric and magneto-electric machines. In all these instruments mechanical power was converted into electricity by the action of magnetism; consequently all were both magneto-electric and dynamo-electric. 1878J. N. Shoolbred Pres. State Electric Lighting 6 For the older form, where permanent magnets are employed, the term ‘magneto-electric’ machine has been retained. 1880A. Siemens in Jrnl. Soc. Telegr. Engin. IX. 93 A constant and permanent magnetic-field is, therefore, of paramount importance, and it can be produced in the way proposed by Mr. Wilde in 1863 for magneto-electric machines by employing a separate machine for exciting the field-magnets of one or more similar machines. 1882S. P. Thompson in Jrnl. Soc. Arts XXXI. 120 The arbitrary distinction between so-called magneto-electric machines and dynamo-electric machines fails when examined carefully. In all these machines a magnet, whether permanently excited, independently excited, or self-excited, is employed to provide a field of magnetic force. And in all of them dynamic power is employed. 1887W. B. Esson Magneto- & Dynamo-electric Machines 22 In all the machines yet described, the electric currents were induced by means of steel magnets, or, as in Wilde's machine, by magnets that were magnetised by the current produced in another machine. Such machines are usually called ‘magneto-electric’ machines, to distinguish them from the ‘dynamo-electric’ machines. 1889Chambers's Encycl. IV. 146/2 The term ‘dynamo-electric’ was at first applied to distinguish those machines which were self-exciting from ‘magneto-electric’ machines, which had permanent magnets to give the field; but this distinction is no longer maintained. 1891J. W. Urquhart Dynamo-Constr. 2 A magneto-electric machine—an apparatus in which steel magnets are used to furnish the ‘magnetic field’—is not strictly by common consent called a dynamo.
So magˌneto-eˈlectrical a., in the same sense.
1836Mullins in Lond. & Edinb. Philos. Mag. Aug. 120 On certain Improvements in the Construction of Magneto-electrical Machines. 1873F. Jenkin Electr. & Magn. xx. §1. 280 It is convenient to retain the name magneto-electrical apparatus for those arrangements in which powerful electric currents are induced in wires moved across a magnetic field produced by permanent magnets or electro-magnets. |