US1964265A - Electromagnetic device - Google Patents

Description

June 26, 1934. a. MARKLEY 1,964,265

ELECTROMAGNETIC DEVICE Original Filed Sept. 30, 1927 2 Sheets-Sheet l 9. 5 INVENTOR.

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ELECTROMAGNETIC DEVICE Original Filed Sept. 30, 1927 2 Sheets-Sheet 2 aw a M} gmye 6/7/0327.

' ATTORNEY v B 53' gym EIIZZZIZE t Patented June 26, 1934 UNITED STATES PATENT OFFICE Application September 30, 1927, Serial No. 223,028 Renewed September 23, 1933 13 Claims. (Cl. 172-240) In the operation of devices requiring a reciprocating or vibrating motion, such for instance as drills, chippers, riveters, hammers, screens, molding and jarring machines, etc., it has been customary heretofore to actuate pneumatically, or in some cases electrically with more or less elaborate interrupter or make and break means. In the latter case, difficulties. enter from destruction at the contacts however, and operation is not reliable and satisfactory. Construction free from these dimculties, and a reliable means for current supply for such and other usages, are

' accordingly highly desirable.

To the accomplishment of the foregoing and related ends, the invention, then, consists of the features hereinafter fully described, and particularly pointed out in the claims, the following description and the annexed drawings setting forthin detail certain structure embodying the 0 invention, such being illustrative however of but a few of the various ways in which the invention may be employed.

In said annexed drawings, Figs. 1 to 4 inclusive are vertical sectional views illustrative of the invention; Fig. 5 is a diagrammatic view showing the form of wave produced by the foregoing; Figs. 6 to 9 inclusive are vertical sectional views of a modification; Fig. 10 is a diagrammatic view showing a form of wave produced thereby; and

80 Fig. 11 is a vertical sectional view of another modification.

If in an assemblage comprising a stator and a rotor there be a winding for each such as to form a bipolar field for instance, and if one winding be connected up with a source of electromotive force and the other be connected in circuit with a point of usage, then with the primary in a position to thread the entire magnetic flux through the secondary, the E. M. F. impressed upon the one winding will for the time induce an E. M. F. in the other. If now the rotor be brought around to a point 90 from the position with windings opposite, the'magnetic field will no longer cross the coils in common and no electromotive force will be induced in the secondary winding. On turning however through a further 90, the positioning will again be \such that maximum E. M. F. is induced. In accordance with the design of pole pieces, and the ratio of turns on primary and secondary, and the character of current supply to the primary winding, an output of cyclic current having a range between maximum and zero may be had, and of voltage as desired.

65 As illustrated in Fig. 1, a stator l of any desired form, more usually of circular type, and preferably of laminated construction, carries pole pieces 2, 3. Upon the pole pieces and preferably well back from the pole faces are secondary windings S, S1. Mounted for movement within the pole pieces is a rotor R carrying a primary winding P which is connected to a suitable source of current. Such current may be single phase or polyphase alternating current, flu'ctuating or an intermittent type of current, and for convenience such variable currents whether alternating or pulsating unidirectional will be hereinafter designated cyclic". The secondary coils may be connected in series, as indicated,

and thence to a point of usage, for instance an electro-magnet for the actuation of a tool or other device.

With current flowing through the primary, and a relative movement provided between primary and secondary, there will be induced in the secondary waves of a frequency corresponding to that of the primary and in addition a modulation thereof depending upon the amount of magnetic flux generated by the primary threading the secondary winding. This fiux threading the secondary is varied by a relative movement of the primary magnetic field (not necessarily the pri-- mary winding) in relation to the secondary winding. Ordinarily it is most convenient to move the primary as mounted on the rotor on the type indi- 35 cated in Figs. 1 and 2. In some cases however, it will be preferred to mount the secondary on the rotor, as indicated in Figs. 3 and 4, 'and'the primary windings will then be placed on the pole pieces and may be connected in series, as indicated. Such a rotor may be driven by any suitable means, as for instance a motor geared or belted to the shaft or directly mounted thereon. In either case, it will be seen that the magnetic field when the windings are in the relative position shown in Fig. 1 will take a mean path along lines M, M, and the secondary coils will then be in a maximum exposure to such flux. When the rotor is turned .99", as in Fig. 2, the magnetic flux will shift however more especially into the iron path presented by the pole pieces, and preferably these are expanded in a manner to provide more effectively such path, and accordingly the secondary coils will be relatively free from magnetic lines of force and no E. M. F. will be therein generated. In other words, with the relative positions of primary and secondary shown in Fig. 1, the E. M. F. induced in the secondary will be a maximum, and in theposition shown in Fig. 2, it will have dropped to zero. With further moveno noticed that the E. M. F. correspondingly starts from zero at the point X when the relative positions of the primary and secondary windings are such that the magnetic lines of force pass through the pole piece path rather than through the secondary, and the magnitude of oscillations of the wave thence increases in accordance with the amount of the magnetic flux generated by the primary which threads the secondary winding and reaches a maximum when the relative positions of the primary and secondary windings are such that the magnetic flux is a maximum through the secondary; and then with further movement such that the magnetic flux is shifted more into the metallic pole pieces the E. M. F. correspondingly falls ofi again to zero at X. The zero period may be gauged as to its duration by the relative proportioning of -the pole piece face portions of the stator as regards the pole piece face portions of the rotor.

Instead of a bipolar machine as illustrated in Figs. 1 to 4, a multipolar machine may be constructed on the same principle, and as illustrated in Figs. 6 to 9 inclusive, such may take the form of a stator 11 of convenient form, and preferably of laminated type, and having pole pieces in pairs, each pole piece carrying a winding. These windings may then be connected in groups in series, as windings S, S1 in one group, and windings S3, S4 in another group. These then being connected out to common or separate points of usage. A rotor R1 carries a primary winding P which is supplied from single phase or polyphase or intermittent type of current supply. The pole pieces are expanded in order to present an extended path for the shifting of the magnetic flux; and as will be readily understood from the foregoing explanation in connection with Fig. 1, when the relative positions of the primary P and the secondary group S, S1 are as shown in Fig. 6, there will be a maximum magnetic flux threading through the secondaries, and the E. M. F. resultant in the secondary circuit will be a maximum, as indicated at Z, Fig. 10. When the primary is then moved through a 45 mechanical are, as illustrated in Fig. '7, the magnetic flux shifts correspondingly and the E. M. F. falls off, so that as the primary is brought to the position shown in Fig. 8, magnetic flux threading through the primary windings S, S1 is Zero, as at point X2, Fig. 10. It will be noticed however that while this is transpiring with respect to the secondary windings S, S1, secondary windings S3, S4, with the relative positions of Fig. 6, were receiving a zero magnetic flux and correspondingly as seen in Fig. 10, when the E. M. F. generated in windings S, S1 was a maximum, the E. M. F. in coils S3, S4 was a minimum, and with the turning to the position of Fig. 7, the E. M, F. in windings S, S1 drops, while that in windings S3, S4 increases, reaching a maximum Z2 when the rotor has come to the position shown in Fig. 8, and so on. In this manner, it will be seen that one secondary group is putting out a maximum E. M. F. at the time that the other is at zero. The relative dwell on zero or on maximum can be gauged as desired, by the relative proportioning of the pole faces opposed to the rotor. By this means, it will be seen that I am enabled to gauge the relative wave shapes of the E. M. F. output over a range of design, making it possible to produce a type of current capable of electro-magnetically moving hammers for instance or other devices having considerable weight, it being readily possible on this basis of controlled acceleration, to secure the movement requisite for relatively large weights or small weights as desired.

In the form shown in Fig. 11, the pole pieces of the stator 21 carry not only the secondary windings S1, S2, S3, S4, but also primary windings P. The latter are connected in series to a line 22 or source of power, for instance single phase alternating current. Polyphase current or other intermittent current may be used. The secondary windings may again be grouped, S1, and S2 being in series, and windings S3 and S4 being another series group. These groups are shown as connected to electro-magnetic coil-windings C1 and C2 respectively, these constituting a solenoid in which travels a solenoid armature A. The rotor R carries no windings, but has its faces opposing the stator poles laid out on arcuate expanses in accordance with the particular factors desired as to maximum and zero E. M. F. in the output, as pointed out above. The secondary windings are positioned well back from the pole faces, and thus with relative movement of the rotor the magnetic flux may readily shift so as to alternately thread through the respective secondaries and the magnetic field will be progressively passed through coil after coil in succession without being broken itself. Correspondingly, each secondary group in its turn will be alternately energized and the solenoid armature A' will be reciprocated back and forth within the solenoid. By providing a desired tool on the car rier armature A, work on the order of drilling, chipping, riveting, hammering, etc. may be readily carried out. In the particular position illustrated, the slight E. M. F. induced in the secondaries S3, S4 due to flow of primary current on the same pole piecesas the counter E. M. F. generated in the primary coils on the poles c'arrying secondaries S3, S4 is killed by the secondaries S3, S4 being short circuited through the coils C1.

In some instances, instead of resorting to two solenoid-coil windings, I may employ one coil winding, and arrange a spring, as f, Fig. 11, to provide movement of the armature core in the opposite direction, for a reciprocatory movement. The particular rate of vibration for the armature or core A will depend upon the frequency, and this in turn will be determined by the rate of revolution of the rotor.

It will thus be seen that a type of current having a considerable range of possible control factors as to duration of maximum and zero, and a relativity of oscillation in plural wave form may be had, and yet by virtue of the fact that the magnetic flux is so controlled as to simply shift from one favorable path to another without the necessitating of magnetic lines of force being broken to large extent, and the winding being so placed that the moving magnetic field does not cut live conductors to any extent, the amount of power required to effect the relative movement of the magnetic field is very small, the power requirement for a machine of the present type being substantially only that requisite to take care of mechanical friction, windage and core and copper losses, and thus a large power unit taking off from a supply line may be actuated in practice by an extremely small motor for the rotor movement, and according to the particular requirements the secondaries may be connected up variously, and may be wound for any number of phases desired.

Other modes of applying the principle of the invention may be employed, change being made as regards the details disclosed, provided the means stated in any of the following claims, or the equivalent of such, be employed.

I therefore particularly point out and distinctly claim as my invention:

1. In apparatus oi the character described, the combination of an electro-magnetic coil, an armature attracted thereby, and means for sup plying periodically modulated current to said coil, said means including a primary winding connected to a source oi a cyclic E. M. R, a secondary winding inductively coupled to said primary winding, and shunt-path means for periodically directing the primary magnetic field away from the secondary winding.

2. In apparatus of the character described, the combination of a solenoid, an armature core operable therein, and means for supplying periodically modulated current to said solenoid, said means including a stator and a rotor, a primary winding connected with a source of alternating current, a secondary winding inductively coupled to said primary winding and conductively connected to said solenoid, and means for peri odically directing the primary magnetic field away from said secondary winding, including means for revolving the rotor.

3. In apparatus of the character described, the combination oi a solenoid, a plurality of coil windings in said solenoid, an armature core operable therein, and means for supplying periodically modulated current successively to said solenoid coil windings, said means including a stator, a rotor providing a magnetic shunt path, primary windings on said stator connected to a source of alternating current, pole-pieceson said stator, and a secondary winding in inductive coupling relation to each primary winding and spaced well back from the pole pieces, the secondary windings being connected with respective coils of the solenoid.

4. In apparatus for converting electric energy, the combination of primary and secondary windings, the secondary winding being connected to a work circuit including an electro-magnet withv movable armature, and the primary winding being connected to a source of cyclic E. M. F., and means for periodically modulating the E. M. F. amplitude in the secondary and thereby correspondingly moving said armature.

5. In apparatus for converting electric energy, the combination of a primary winding energized by a cyclic E..M. F., a secondary winding inductively coupled to said primary winding and conductively connected to a work circuit including an electro-magnet with an armature movable to and fro, and means for periodically modulating the amplitude swing in said secondary winding and thereby periodically moving said armature, said means including means for directing the primary magnetic field away from the secondary winding. v

6. In appmtiu for converting electric energy, the combination 01' a primary winding energized by a cyclic E. M. 1"., a secondary winding inductively coupled to said primary winding and cona stator and a rotor,-including a winding conductively connected to a work circuit including an electro-magnet with a reciprocable armature, and means for periodically modulating the amplitude swing in said secondary winding and thereby periodically reciprocating said armature, said means including a rotor periodically directing the primary magnetic field away from said secondary winding.

7. In apparatus for converting electric energy,

nected with a source of alternating current, a secondary winding connected to a work circuit including an electro-magnet with a reciprocable armature, and means for periodically modulating the E. M. F. amplitude in the secondary winding and thereby reciprocating said armature, said means including a periodically operated shunt path of low reluctance for the magnetic flux.

8. In apparatus for converting electric energy, means for producing a modulated undulatory current having periodic crests of maximum E. M. F. and intervening troughs of sustained minimum E. M. F. and an electro-magnet supplied thereby having an armature movable in response. to the pull and release magnetic field-provided by such modulated current. r

9. In an apparatus for converting electrical energy into mechanical energy, a primary wind ing connected to a source of alternating electro motive force and a. secondary winding disposed in inductive relation thereto whereby alternating flux generated -by the primary winding mayinduce electro-motive force in the secondary winding, a power-supplying device comprising an electro-magnet having a winding and a movable armature and the winding being connected to the secondary winding to be energized thereby, and means for periodically modulating the electro-motive force in the secondary circuit to cause it to energize the electro-m'agnetic winding with periodic waves of energization of a frequency less than that of the source, to periodically exert tractive etl'ort on the armature, said modulating means including a ferrous'element movable to periodically vary the reluctance oi. the path of the flux in the secondary winding, and means for so moving the element.

10. In an apparatus for converting electrical energy into mechanical energy, a primary winding connected to a source 01 alternating 'electro- 5 motive force and a secondary winding disposed in inductive relation thereto whereby alternating flux generated by the primary winding may induce electro-motive force in the secondary winding, a power-supplying device comprising an elec- 139 tro-magnet having a winding and a movable armature and the winding being connected to the secondary winding to be energized thereby, and means for periodically modulating the electromotive force in the secondary circuit to cause it to energize the electro-magnetic winding with periodic waves of energization alternating with periods of zero energization, to periodically exert tractive effort on the armature, said modulating means including a ferrous element movable to periodically vary the reluctance of the path oi. the flux in the secondary winding, and means for so moving the element.

11. In an apparatus for converting electrical energy into mechanical energy, ,a plurality oi 15 secondary windings, a power-supplying device comprising a plurality of eleetro-magnetic windings ea'ch energizable by current in a corresponding secondary winding, and an armature means H movable in response to energization of each winding, a primary circuit connected to a source of alternating electro-motive force and disposed in inductive relation to the said secondary windings whereby alternating current in the primary circuit may induce electro-motive force in the secondary windings, means for periodically modulating the electro-motive forces in the secondary windings to cause them to energize the electromagnetic windings with periodic waves of energization of a frequency less than that of the source, and with the wave in one electro-magnetic winding in displaced time phase relation to that in another to cause the electro-magnetic windings to periodically and successively exert tractive effort on their armature means, said modulating means including a ferrous element movable to periodically vary the reluctance of the path of the flux in the secondary windings, and means for so, moving the element.

12. In an apparatus for converting electrical energy into mechanical energy, a plurality of secondary windings, a power-supplying device comprising a plurality of electro-magnetic windings each energizable by current in a corresponding secondary winding, an armature means movable responsive to energization of each winding, a primary circuit connected to a source of alternating electro-motive force and disposed in inductive relation to the said secondary windings whereby alternating current in the primary circuit may induce electro-motive force in the secondary windings, means for periodically modulating the electro-motive forces in the secondary windings to cause them to energize the electro-magnetic windings with periodic waves of energization a1- ternating with periods of zero energization and with the wave in one electro-magnet occurring in time phase relation with the zero period of another electro-magnet to cause the electromagnets to periodically and successively exert tractive effort on their armature means, said modulating means including a ferrous element movable to periodically vary the reluctance of the path of the flux in the secondary windings, and means for so moving the element.

13. In an apparatus for converting electrical energy into mechanical energy, a plurality of primary windings connected to a source of alternating electro-motive force, a secondary winding disposed in inductive relation to each primary winding whereby alternating flux generated by the primary windings may induce electro-motive force inthe corresponding secondary winding, the secondary windings being connected in groups, a work circuit connected with each group, a power-supplying device comprising a plurality of electro-magnetic windings and a movable armature means for each winding and each winding being connected to one of the groups of the secondary windings, to be energized thereby, means for periodically modulating the electromotive force in the secondary windings to cause them to energize the electro-magnetic windings with periodic waves of energization and with the Wave in one electro-magnetic winding in displaced time phase relation to that in another to cause the electro-magnets to periodically and successively exert tractive effort on their armature means, said modulating means including a rotary ferrous element disposed with respect to the path of the flux in the secondary windings of the respective groups so that upon rotation it may periodically vary the reluctance of the paths, and means for so rotating the rotary element.

GEORGE E. MARKLEY.

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