US1002712A - Electromagnetic device for alternating currents. - Google Patents

Description

G. D. LANNING. ELEGTROMAGNETIG DEVICE FOR ALTERNATING OURRENTS.

APPLICATION FILED AUG. 2, 1910.

1,002,71 2. Patented Sept. 5, 1911.

2 SHEETSSHEET 1.

witnesses I maven/$0 z".- finm a. 16 GhariesBLa uni/n C. D. LANNING.

ELECTROMAGNETIC DEVICE FOR ALTERNATING CURRENTS.

APPLICATION FILED AUG. 2, 1910.

2 SHBETSSHBET 2.

WW Q fg www' L aalahs To all whom it mag concern:

CHABLES D. LANNING, OF BOSTON, JVIASSACHUSETTS.

ELECTROMAGNETIC DEVICE FOR ALTERNAT ING CURRENTS.

Specification of Letters Patent.

' Patented Sept. 5, 191.1.

- Application filed August 2, 1910. Serial no. 575,051.

Be it known that I, CHARLES D, LANNING, a citizen of the United States, and a resident of Boston, in the county of Suffolk, State of Massachusetts, have invented an Improvement in Electromagnetic Devices for Alternating Currents, of which the following description, in connection with the accompanying drawings, is a specification, like letters on the drawings representing like parts.

This invention relates to electro-magnetic devices, more particularly to those intended to be energized by alternating currents, and has particular reference to improvements in the efliciency of electro-magnets which are energized by alternating currents, and particularly those of relatively slight strength andhigh frequency, such, for example, as telephonic .currents or the like.

My invention will be best understood by reference to the following description when taken in connection with the accompanying illustration of one specific embodiment thereof, while its scope will be more particularly pointed out in the appended claims.

In the drawings: diagrammatically a circuit arrangement, embodying one form of my invention; Fig. 2 is a plan view of a switch which may be employed in the arrangement shown in" Fig. 1; Fig. 3 is a central section in elevation, partially broken away, and on an enlarged scale,'showing the construction of the switch disclosed in Fig. 2; and Fig. 4 is a detail of the connection between the switch arm and its controlling spring.

Referring to Fig. 1 of the drawings, I have there illustrated one form of'my in vention applied to a telephone system, and to'an instance where it is necessary to control a switch or other device by means of a magnet energized by the voice-caused alternating currents on the telephone line. In this particular instance the telephone circuit is provided with a repeating station having circuit-changing means for establishing repeating relations between the sending and receiving station, such circuitchanging means being controlled by a voice energized electro-magnet.

Referring to the diagrammatic showing in Fig. 1, there is conveniently represented at 1 a telephone station which may be adapted both for the transmission and the receipt Figure 1 represents of telephonic currents, such station being connected with the repeating station by the line circuits 2 and 3. The line 2 is split into two branches 4.- and 5, the former passing through the primary of the transmitting induction coil (3, and thence through the primary of the switch controlling induction coil 7 to the switch contact 8. The latter is normally engaged bythe pivotally mounted switch 9, the latter being maintained iIl such position by the spring or other restoring member 10. The other branch 5' of the circuit 2 forms a receiving'circuit leading to the secondary of the receiving coil 11, and thence to the normally opened switch-com trolled contact 12 at the switch 9. The opposite side 8 of the transmitting circuit is permanently connected to the controlling switch 9 by any suitable means as, for eX-. ample, through the restoring spring 10. \Vhile the switch 9 normally engages the contact 8, it may be withdrawn therefrom and moved to engage the contact 12 on energizatio-n of the switch-controlling electromagnet 13.

Referring now to the sending and receivin station 14: at the opposite end of the line, the main circuits 15 and 16 lead to the repeating station and have connections corresponding generally to those already described, which it will not be necessary again to enumerate, there being provided, howover, for these circuits a controlling switch 17 similar to the switch 9, switch contacts 18 and 19, a switch-operating magnet 20 and a restoring spring 21. y i

It will be seen that in the normal state of the apparatus, with the magnets deenergized, the connections remain as shown in the diagram; In the arrangement shown I rely upon the initially transmitted voicecaused telephone-currents to energize the proper magnet and throw the switch to make the requisite repeating connections. To energize the proper magnet, each magn'lat is connected in series with the secondary of its switch-controlling induction coil, and, to secure the best results, I have made special provision for rectifying the alternating currents which pass from the coil to the magnet, thereby providing a uni-directional magnetizing current. To this end the magnetwinding 22 has interposed between it and the induction coil a suitable rectifying element, such as an asymmetrical cell 23,

the well-known property of which is to tional character.

- also connected prevent the current from passing in one di;

rection while permittingit to passin the opposite direction. Such asymmetrical element may be provided in any desired-form,

as, for example, in the form of a cell having lead'and aluminum electrodes immersed in an alkaline electrolyte such as a sodium 'ortho-phosphate solution. Such an asyinmetrical cell when placed in an alternating current circuit odors very, little resistance when the current passes in at the lead electrode and out at the aluminum electrode, but when-the current is reversed it meets with a heavy resistance due to a thin filma separate branch circuit from the winding 22 and having serially related there- 'to another asymmetrical element, such as the asymmetrical cell 25. The two magnet win'dings' 22 and 24 are so connected through their respective asymmetrical elements to the terminals of the induction coil secondary that they tend to reinforce each "the other,and establish each a magnetic field of the same polarity. It therefore follows that, in-eaeh alternating current cycle,

the cessation of the decreasing magnetizing current in one circuit is immediately succeeded by the flow of an increasing magnet- 12mg current in the other circuit, having the same direction and magnetizing effect.

This not only provides against reversal in the magnet current but actually leaves no interval. of demagnetization, for, at the neutral point, a. when theoretically, between the two pulsations there is no current, the'magnet still tends to attract the switch through the residual or remainant magnetism;

Turning again to the curcuit connections in Fig. 1', the effect of'throwing the switch 17, by means of the voice currents'transmitted from the station 1, is'to interruptthe transmitting circuit from the station 14,

through the branches 26 and 27,- at the contact 1 8 and to complete the receiving circuit passing thereto through the branches 28 and 29. Under such conditions the voice currents generated. at the station 1 are reproduced in the receiving circuit of the station 14 through the interposition of suitable repeating devices. For this purpose, there is interposed between the primary of the transformer 6, which is in the branch 4 of i the main line circuit 2, and the secondary of the transformer 30, which is in the receiving branch 28 of the main line circuit 15, a repeater 31 which I have shown in' conventional diagrammatic form, but which may be of any design. or construction adapted to reproduce accurately, and preferably with increased intensity, the electrical undulations of the circuit 2'3, again in the secondary of the transformer 30. This repeater herein shown consists of a magnet coil in circuit with the secondary of the transformer 6 and having an armature adapted to vary the pressure in a suitable form of carbon or microphonic contact,

thereby varying the current flowing in the primary of the transformer 30. lVith the switch l7, 'therefore,'in the dotted line position shown, undulations in the circuit 2-3 are thus reproduced in the secondary of the transformer 80 and transmitted to the main line circuit through the branch or receiving circuits 28, 29, and thus to the distant.sta-

tion. At the same time the transmitting circuit on the lines 2627 being open at the switch, the associatedtransmitting apparatus for station 14 is, therefore, unali'ected by any energy subsequently transmitted over th'eline 23 from the station. As soon as transmission of voice energy from the'station 1 ceases, the magnet 20, being thereupon .deenergized, the switch 17 is restored by the spring 21 to the position shown in full lines, breaking'from the receiving branch 28 for the station ii and again completing the circuit for the transmitting branches 26, 27 thereof, leaving the repeater in condition again to pass under the control of the next voice currents to pass over the line. Ifvoice energy is transmitted from the station 14 to the station 1 the transmitting branch for the station 1 is immediately broken by the movement of the switch 9, which at the same time completes the receiving branch thereof and the voice energy from the line 15, 16 is reproduced with intensification in the line circuit 23, through the. repeater 32, all of which will be readily understood from the. foregoing description. The cir-' cuit control is, therefore, automatically effected by the telephone currents themselves, the switch corresponding to that terminal station toward which. the voice energy is transmitted, being instantly thrown, through the medium of its controlling electro-magnet. to break its transmitting circuit and place its receiving circuit in condition to receive and pass on the voice-actuated currents.

It will be observed that the asymmetrical cells 23 and 25 are not in the main telephonic circuit but that the circuit containing the same is inductionally related to the main line clrcuit so that the telcphonlc currents do not actually pass through these cells and the main telepl'ionic line circuit cannot be ati'ccted by any variations in resistance of th A asyunnetrical elements.

In the control of a switch, such as described, by means of an elcctro-magnet energized through alternating currents, as, for example, telephone currents, it is ordinarily necessary to provide a spring or other restoring member, having a low rate of vibration which, in the case oftelephone currents, should be less than the lowest audible tone of the human voice. Otherwise the reversal in the magnetizingcurrent of the magnet will", at the zero point of magnetism, tend to release the switch and allow the spring to restore the same to its normal position, so that the alternations o't'current willv tend to induce a sympathetic vibration in the spring instead of holding the switch steadily attracted during the alternating passage of the current through the magnetic coils. in a magnet wound and energized as dcscribec, however, the precaution of an abnormally low period of vibration for the spring is unnecessary, since the switch will remain attracted by the magnet so long as the restoring force of the spring is than the remainantmagnetism which is effective be tween the succeeding uni-directional pulsations. Furthermore, since there is no reversal of the magnetizing current, a more effective magnetism 1s secured 'lrom a given strength of alternating current, which is particularly advantageous in the case of telephone currents and other weak currents, partlcularly those of hlgh periodicity where self-induction and hysteresisflosscs are apt to be great.

In Figs. 2 to 4: I have illustrated the-details of a'controlling switch which may be employed in connection with a system like I that described in Fig. 1. Referring to the drawings, the switch parts are mounted upon a base 45 of insulating material. The switch arm 46 is a small piece of some light conductive material, preferably aluminum, which is shown drilled out further to lighten the same. The switch arm is delicately and sensitively supported by a pivoted pin 4t? mounted in jeweled cup bearings 48, so that may execute the slight movement necessary with a minimum amount of friction.

and inertia. The upper bearing is shown ad prstable by means of a thumb screw 49 and dock nut 50. The switch controlling magnet 51 is suitably supported upon ahase to face a thin, light armature 52, preferably a piece of soft. thin-sheet iron secured to the end of the switch arm. The double or parallel windings of the magnetic coils are connected to the terminal binding posts 54, 55 and 5t) and are mounted upon the ends of the horse shoe core 57 as close t0 the armature as possible. The core 57 is preferably of posts soft laminated iron. The .stationary contacts are shown in the form of adjustable screws 58 and 59 adjustably mounted in posts 60 and 61 and preferably tipped with platinum ends which cooperate with platinum contacts 62 upon the switch arm. The and 61 are connected, respectively, to terminal posts 63 and 64. The switch arm l6 is normally held in contact wit one of the contact screws (with screw 09 in Fig. 2) by means of a resilient restoring member, the same herein comprising a relatively long, fine, flexible wire 65 having one end resting in the V-shaped groove of an upturned ear 66 (see Fig. 4:) on the rear end of the switch arm, and the opposite end held fixed in a block G'Tfwhich may be slightly adjusted transverse the axis of the wire in the fixed frame 68 by means of tlie fine differential adjpsting. screw 69. The'wire 65 is preferably of iridium-platinum and so finely dimensioned asto exert a very deli cate restoring tendency upon the switch 'arm. (*onnections may be made to the switch arm through the platinum wire 65, thesliding block 67 and frame 68 by means of the lead wire 70 and the binding post- 71.i By adjusting the block (37, the restoring tendency of the spring may be adjusted.

To obtain the-best results and maintain the switch in perfectbalance, the base 45 is provided with the leveling screws 72 and the spirit level 7 3.

It will be understood that my invention is not limited to the particular details" herein shown, either of construction, circuit arrangement or application of the invention, these being submitted for purposes of illustration only, but that extensive deviations maybe made therefrom without deperating from the spirit of the invention.

Having thus described my invention,what I claim is:

'1. In a telephone relay system a. two-way repeating device comprising one or more repeating instruments, circuit controlling means for establishing and maintaining the circuits to and fromthe repeating device according to the direction of sound trans mission from the speaking to the listening station, an electro-magnet for actuating said circuit controlling means, said electro-magnet being energized through the voice caused currents from the speaking station, and current rectifying means for providing a uni-directional current for the said magnet.

, 2. In a telephone relay system a two-way repeating device and a line circuit leading from each station thereto, said repeating device including a circuit-changing device for placing either station in suitable repeating communication with the otheraccording to the direction of sound transmis sion, an electro-magnet actuated by the lOt - c" 'pies of this patent may be'obtaincdfor voice currents in either'line circuit for op erating said circuit-changing device, parallel windings for said magnet, and an asymmetrical element associated with each Winding for causing-current impulses alternately through the two windings having a-uni-dircctional magnetizing effect.

3. In a telephone relay system, a repeating station; terminal stations having line circuits leading to said repeating station; a transmitting. circuit and receiving circuit for each line circuit at said repeating station; and means for automatically breaking the receiving circuit from one stat-ion and making the corresponding transmitting circuit on the passage of voice currents from the opposite terminal station, said means comprising an electro-magnetic device energized'by the said voice currents; and currentrectifyingmeans for. providing thercfor from the said voice currents, a uni-directional magnetizing current.

telephone apparatus of the class de scribed having means for reproducing telephonicspe'ech, sounds or the like alternately from one main line circuit into another main line circuit consisting of a telephone transmitter lndu'ctlon coll, a source of elcctro-motive. force and circuit connections, electromagnetic apparatus rcsponsive to the voice I caused currents originated at'either sending LANNING.

five cents each, by addressing the Commissioner of latents. Washington, D. C.

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