US1108320A - Electric-current-controlling apparatus. - Google Patents

Description

A. E. BERDON. ELECTRIC CURRENT GONTROLLING APPARATUS.

l APPLICATION FILED KAY 10, 1913. 1,108,320. Patented Aug. 25, 1.9M

l cation Serial No. 7 66,873, V,filed ,ofeven normal direction. to have the current reversed 1n order to open 7 UNITED sTATEs PATENT orifice; l

ALBERT E. BERDON, 0F INDIANAPOLIS, INDIANA.

y ELncTRrc-CURRENT-CONTROLLINGAPPARATUS.

Specification of Letters-Patent.

Patented Aug. 25, 1914.

Application flied May 1o, i913. serial No. 766,574.

Tof/lll 'whom it may concern Be it known that I, ALBERT E. BEnDoN, citizen of the United States, residing` at Indianapolis, in the county of Marion and State of Indiana, have invented a certain new and useful Improvement in Electric- Current-Controlling Apparatus, of which maintained closed as long as any current is flowing in the-positive or normal-direction, opening of the working circuit be1n0 permitted at a time when thecurrent is o zero value 'or is very slightly reversed. If

desired, the working circuit may be also `opened when the'current reaches a predetenmined minimum value in the positive or It need not be'essential the main working circuit switch contacts, though it is to be understood thatthe apparatus is to be, adjusted to have these contacts open when the current reaches any p1 edetermined value in the normal or positive and reverse directions. The apparatusv may be adjusted' to open the main orworking circuit quickly and positively, when such opening is. to ,be occasioned-by reyerse cury rent, by permitting such reversedcurrentto reduce the effective magnetism 1n the magnetic circuit of the circuit controlling, mag.-w

net. The magnet which emply'is .desirably that disclosed in my t(x0-pending appliate herewith. 4 y I will explain my invent-ion. more fully by reference to the accompanying drawing showing the preferred4 embodimentthereof and in which- .Ffgure l isa ,diagrammatic-view illustrating theinvention; Fig. Q.isv a plan-view of some of the structural partsillust'ra'ted in Fig. l; and 3 and 4 ,are diagrams illustrating the magnetic ux. v I

Like parts areiindic'ated by similar charyactersof reference throughout the diiierent figures.

Referring first particularly' to Figs.- 3 'and i '4, I will first describe the magnetl which ment. This`magnet ypreferably includes no ipermanent magnet in its formation, the lwinding core l being preferably of soft unlaminated iron having soft iron polar eX- tensions 2 and 3 secured toits ends by means of screws 4, these'soft iron polar extensions extending laterally of the core fora suicient distance upon each side of the core to' ,i alford properlimits to the magnet winding space and each being inturned in 'approaching directions upon oneside of the coreas indicated at 5, va suitable gap intervening between the inturned polar extension ends there to constitute a gap in the magnetic circuit. lvThis gap is bridged by a soft iron armature G whose lower face is formed-with a rounded fulcrumridge 7 affording a'rolling contact between the armature and one of thepolar extensions 3 upon which the armature is supported adjacent the ap between the polar extensions.v The ulcru'm ridge `7 is located substantially midway be-Y tween the ends ofy the armature 6 whereby the armaturev is caused preferably to overlie substantially all of the insetting extension of the polar extension 3 upon which the armature is mounted, the otherend of vpreferably constitutes', a part of the equpss.l

the armaturejoverlying a sufiicientportion of the insetting extension ofthe other polar extension 2 to enable theproper passage of the-,magnetic flux. In the absence 4ofpsuiiicient tracti've `effort lbetween the polar extension .Q and `the armature 6, a spring v8 operates tfo'idrawthe right-hand end of .the

armature" v'downwlardly until the non-niag-':

netic stopj9 engages the vpolar'.'c axten'sic'nn 3'. VheIi' 'the'.magnetic `attraction 1s suicient,

'move the armature'in 'a 'counterclockwise direction, the'extent' off movement thls direction benglimited byla stopl() ofY non- Alm lgnetic material "adapted for ,engagement zwith the polar extensionQ. The force f 'the springis regulated' by"A a ,horizontallyE h djustable 'screw' 111 workin upon the ad]a cent and inclined end of the'sprin-g l'8. g e spring operates upon the armaturethrugh the intermediation of the strutzlj'fsv'vingjingly connected at its upper end "with the armature and at its. lower end with a spring tongue 13 projecting upwardly from and being integrally formed with the spring.8.

The flux set up within the magnetic cir-r cuit established by the elements 1, 2, 3, 6 and 7 is diagrammatically indicated in Figs. and a by the flux lines having the arrow heads Ipointing ai direction of flux. 'llhc fulcrum ridge 7 is integrally formed with the 9 armature 6 and-has magnetic contact with .the pelar extension 3, the lines of force hav- "ing one ilis'ti'iln1tion 'at the armature when Y the armature ist unattracted and another distribution when thearmature is attracted, i5 the-'portions'of lthe lower armature acebei ing desi'rlablyangularlyy related to permit .nture continues to move in responsetoits :o magnetic attraction whereby the magnetic reluctance at its right hand air gap in' creases and progressively increases toward the right hand limit of the armature so as to effect a progressively increasing concentration of the linesfottorce toward and. at the fulcrum ridge thereby progressively/.to reduce the magnetic Apull upon the right hand endof the armature as tfhe armature is moving to itsvmagnetically attracted pofn '0 'sition whereby the flux across the air gap fat thejleft hand'end .of the armature, as it is 'progressively shortened,- may cause the more rapid positive'f-'closing movement of z the armature, the :magnetic opposition to such closing movementfat the right hand end `or the armature' being rariidly-and..A progressively decreased as will be understood for reasons above explained and owing also to thelengthening of the portionsoi" the-lines of force that span theprogressively increasing air gap at the right hand end of the armature.. Thus all.the lux traverses the gap at the left handA end of-the armature while .the portion which .traverses the gap at the right hand Vend of the armature prov gressively decreases as this latter gap is widened, a result which is rendered possible `[owing to the'reduction of magneticreluctanceat 7 where a path lis aorded for increasing flux diverted therethrough owing to the increasing reluctance at the rightfof the armature. In. otherwords there is but one tluX path at the leftof the armature and` there are two nuri paths at the righthand portion of the amature, one of these latternioaeao twotilnx pathsincluding the ulcrum 7 and lirst'of `these two shuntrelated paths from the secend of such paths as the right hand air ga increases and more being diverted throng the second of such paths Vfrom the jlirst aslthis right hand air gap decreases.

The s acing intervening between the tulcrum and the lett hand air gap is selected to 'enable the flux there to eii'ect magnetic attraction as desired, the sum of the lines of forcent the' leit hand air gap multiplied by ntheir respective distances from the fulcrum 7 lquickly becoming greater than a similar summation at the right hand air gap when 'the armature is being magnetically attracted.` As' soon as the armature moves the slightest owing t'o magnetic attraction a rej'distribution of the flux along the lines above 4set forth is immediately commenced and rapidly continues to insure a rapid and complete closing stroke of the armature after the initial unbalancing of the flux at 'the opposite ends of the armature occurs ythe tendency .of the armature 6 Vto continue `the entire stroke upon which it has coinrnenced being sostrong that 1t will take its full movement even though the initial magnetizing force'required to start the movementhe largely'reduced. |lfhe strip metal springs 17 and 18 carry disk-shaped contacts 27, 28, the strip metal spring 25 engaging the spring 18 near the outer peripheral portion of the disk contact 28 for the purpose of `vso nexing the spring 18 as to enable the opposing'faces of the contacts 27 and 28 to :1

be in exact parallelismv'when .the contact 27 is on the point of application to the contact 2Sr when the spring 17 carrying contact27 is moved upwardly by the armature through 'the' intermediation of the insulating post ,24, wherebv the adjacent faces of these contacts are initially in engagement throughout to prevent undue introduction of resistance Y at this pointvof contact. The stop 26 is adjustable to. enable the spring 18 to be properly initiallyl positioned, the stop 26 operating upon the spring 18 through the spring 25. The spring 17 carries a lower contact engaging a normal contact upon the spring `21. extent to which the spring 21 may be flexed upwardly due to its own resilience when' the Spring 17 isiiaed. f

An adjustable post 23 limits the Referring nowalso to Figs. 1 and 2, a suitably driven vdirect current generator 1 4: 1-5 of low voltage, say siX volts, is in serial relation. with the current coil l5 disposed about the core 1 and of comparatively few turns and negligible resistance, wound in such direction that current in the normal or desired directidn tendstoproduce iuxin a direction corresponding tothe flux lset up by the pressure Winding 16 (which is also dis-.

'posed about the. core 1 but normaliydn shunt of the elements 14 and 15) when the `forded by the elements 1,2, 3 and 6. The

voltcoil 16 is high Wound with 'reference to' the coil 15 and is designed to withstand' full potential of the source of current being controlled Without injurious heating. The coils 15 and 16 are cumulatively Wound assuming' `the voltage to be of normal polarity, The

coil 15 is included in a circuit that contains spring 17, spring 18 and a .battery 19 Which may be a three cell, .six volt storage battery adapted to supply a Anumber of sixI volt lamps or otliei" load 20 with current when the switch 201 is closed, the generator 11 being included in the circuit that contains said spring 18 and battery 19. The shuntpath including the. pressure Winding 16 is multiplied from the left hand terminal of the Winding 16, one of these multiplied paths including thenormal follow-up spring contact 21 and the spring17 yfollowed by contact 21 and the other includin the Windin 227 (normally short circuited y springs 1 and 21), the shunt connection effected for the coil 16 With the Winding 15 by Wayoi thecoil 22 being 'permanent While the shunt connection of the coil- .1 6 with the coil V15 through tlie springs 17 and 21 is adapted to be made and broken at these springs due to the, operation of the magnet.

i ratus let it be assumed that the generator 14 In describing the operation of the appais started from rest and' radually increases to its maiiimum speed. he generator voltvage rises'from Zero asthe generator speed 'be traced from the positive brush of the- ,generator 14 through the series Winding 15 increases and a circiiitis initially present traceable from the positive brush of the genei'atorthrough the series coil 15, the spring 17, the spring 21,A the high Wound voltage .'coil 16, to the negative generator brush.

Another circuit is initially present and may the resistance' coil 22, the high Wound voltage coil 16, to the negative brush of the generator. In this condition of tliings'the nori'nally engaged contacts :of tlies'prings 17 and 21 short circuit*the coil 22,` t his conv-v dition remaining until the voltage of the generator rises to a predetermined value (in the example chosen say 6.8.r volts by Way vof illustration) whereupon -the magnetic flux at the left hand end of the armature 6 overcomes'the flux at the right hand end of thev armature and the supplementing pull Vof l the strut to which may be addedthat the armature completing its full stroke even though `the force required to move it inagi 70 rapid, for the reasonsherein pointed out,

netically be greatlyreduced. When the arff mature is magneticallymoved it first causes engagement between springs 17 and 18 and thereafter causes the engagement" between thesprings 17 and21 to 'be broken, the con'- tacts of these latter springs being followup'contacts?v Altered circuit conditions are now consequent, one circuit being traceable from tlieqpo'sitiye brush `of the generator 14y through the series coil 15, theres'istance coil 22, Athe lvoltage. coil 16,V to the Nnegative brush .of the generator, the short circuit about the coil 22 having been broken owing to the separation 'of the" springs 17 and 21. The coil 22 'now in shunt of the generator by Way of coil' 16 and also introduced into circuit ywith the coil4 15, being differentially:

Wound with respectto ythe coils 15 and 16,'

reduces the magnetizing effect of the coils 1 5 and 16 upon the `core- 1 so that if there be no current, or current o f minimum value ,i

in the normal direction, o'r sm'allcurent in an abnormal or negative' direction, (according' to the adjustment of the equipment) owing in the coil 15 tl'ievsp'ring 8 Will be effective to retract the armature to its norinal magnetically unattracted position. In

practice this reduction'of themagnetizing` effect of the coil 16 amounts fto forty `or fifty' per cent., this reduction being largely acof coil 22 and being partly accomplishedby the V reduction of the effeotiveai'npere tiirns `on corel by virtue Aof the opposing direccomplishedvby reducing the current" through f the coil 16 by virtue ofthe ohmic resistance tions of current in the coils 42 and 16. The

function' effected by the ohrnic jresis'tanceof the vcoil 2 2 is obviously accomplished Whethenth'is coil be in or outof magnetizing relation to tlie core 1, and this aspect ofthe invention is not tobe limited tothe Winding of the coil 22 upon the core `1. The oppos' ingL magnetomotive force vset upby the coil 22 'is a factor which is not necessarily dependent upon the ohmic resistance of the coil 22 'and this aspect of the-invention is not to be limited to a high resistance for the.

- By my equipment there are obtained oper.

iis

, no" 'coil 22 Wli'enit is in magnetizing relation' to. Athecore 1.

ating losses which are low and liih eier- 'voltage protection and also thatwhicli is'of utmost importance, namely, the separatipn pf the springs 17 and 18 Whentl'ie current 5 has been reduced toi zero or the minimum or say a very small'reverse Value, according to the adjustment of the equipment, .the

leef

contacts being thus protected from arcing.

The generator is also rendered safe from having its fields reversed due to the big reversed currents flowing in the series winding from the battery possible in" some outfits.

lln thc magnetically y unattracted (or spring actuated) position of the armature 3 with the voltage below 6.8,' the generator cannot send any current through the working circuit although the battery can send current through such circuit if the switch 2017be closed. With the aranature in its magnetically attracted position a circuit ymay be traced from the .positive brush of the generator 14 through the series coil 15, the

springslY and 18 (the spring portion 25 also being 'included in this circuit,it being v`in parallel with the spring 18) the positive terminal of the battery 1S), the negative terminal of this battery, to the negative brush oiE the generator. Upon increase of the generator speed beyond the speed required to impress 6.8 volts, the voltage is kept down to that of the battery voltage plus the rey .sist-ance timescurrent (l. R. drop) of the series coil 15 and the line Wiring, the main contacts remaining closed for all positive values or all predetermined positive values of current.` As the speed of the generator reduces gradually current through the battery reduces until the generator voltage and battery voltage are equal, at which time no current will flow to the main circuit. If the controller is properly set by the adjustment of the screw 11 upon the spring 8, the armature will then Yopen and return to its origil. nal position, it being assumed that the apparatus is to be adjusted thus to operate when there .is no current ilowing. In practice `it hasbeen found advantageous to enable the apparatus to operate at zero current -or at one-quarter to one-half ampere maximum vreverse current. lli/'hen the arlmature begins to move to its original magneticallyv unattracted position it quickly makes the entire stroke, contact `between the springs 17 and21 being made before contact between the springs 17 andl 18 is broken. By way of example but in no wise limiting theA scope of the invention, values and dimensions jmay be assignedl as follows: Cun.

. rent coil 15, negligible resistance., may in clude eighteen turns of No. 12 (Brown t Sharpe gage) copperwire. Resistance winding 22 may be ofl twenty-two ohms resistance and have forty-tour turns No. 27 Ideal wire. Pressure winding 16 may be of seventeen ohms having nine hundred twenty-five turns No. 29 D. C. C. copper wire.

In the equipment illustrated it is possible to have current through the coil 15 reverse in di- J rection while current 1n coil 16 remains 1n its 8 were set so'yweak that a reduction of line direction, a result that would follow if spring 'incasso voltage below battery voltage would not cause contacts 27, 28 to open, reverse current consequently flowing through the coil .15 while the voltage impressed 'upon the coil y turns furnished by the coil 16 or by reduc ing the ampere turns of the coil 16 owing to the ohmic resistance of the element 22, these two functions being both accomplished by the saine element 22 in the preferred'embodiment of the invention.

)While l have herein shown and particularly described the ypreferred embodiment of my invention ll do not wish to be limited 9a toA the precise construction and circuit arrangement shown as changes may readily be made without departing from the spirit of my invention, but

Having thus described my invention l claim. as new and desire to secure by Letters Patent the following :--J f 1. An electric current `controlling device and an electric 'circuit controlled thereby,

which circuit has a current supplying generator, said device including an electro-magnet having an energizing current winding receiving current from the controlled circuit, an energizing pressure winding subject to the pressure of such circuit, these two wind; 105 ings being cumulativelywound, and a thirdL y energizing Winding of high resistance compared with the first energizing winding and differentially wound with respect to the aforesaid windings; and a switch having a 1l@ contact actuated bythe magnet and serially in the controlled circuit, a normal follow-up contact engaging the first contact and by which follow-up contact the second winding is included in shunt of the generator, and an 115 alternate contact serially inthe controlled circuit and engaged by the first contact before the rst contact leaves its normal follow-up contact, the first two contacts having circuit association causing them, by their engagement, to shunt'the third winding from the remaining windings and by their separation to bring the third winding in shunt of the generator by way of the second winding,

while the latter two contacts, by their engagement, serve to establish the controlled v circuit. v

2. An electric `current controlling device and an electric circuit controlled thereby,

which circuit has a current supplying generator, said device including an electro-magnet having an energizing current winding .receiviiig current from the controlled circuit, an lenergizing pressure winding subject to the pressure of such eircuitthese'l two windings' being cumulatively wound, and a third the generator, and an alternate contact se` rially in the controlled circuit and engaged by the first contact before the first contact leaves its normal follow-up contact, the first two contacts having circuit association causing them, by their engagement, to shunt the third winding from the remaining windings and by their separation to bring the third winding in shunt of the generator 'by way ofthe second winding, while the latter two contacts, by theirr engagement, serve to establish the controlled circuit. v

8. An electric current controlling device and an electric circuit controlled thereby, which circuit has a current supplying generator, said device including an electro-magnet having an' energizing current winding re-y ceiving current from the controlled circuit, and an energizing pressure winding subject to. thepressure of such circuit, these two windings being cumulativelywound; a re- Avsistance'that is high compared with thev first aforesaid winding; and a switch having a contact actuated by the magnet and serially,

in the controlled circuit anormal follow-up contact engagingl the first contact and by "Whichffo'lloweu contact the second winding is included s unt of the generator, and an alternate contactfserially in the controlled circuit and engaged by the irs't'contact be` forethe first contact leaves its normal follow-up 'contactythe first two contacts havingl circuitA association' causing Ithem, by ytheir engagement, to shunt the resistance from the windings and by their-separation to bring the second winding in shunt of the generator by way ofthe resistance, whilethe'latterl twocontacts', by their engagement, serve to establish the controlled circuit.A s v I 4. :Ari electric 'current controlling device andjfaiiA electric circuit `controlled thereby, whieh circuit has a current supplying genen A ator, device-including an electro-magnet haring .fm-energizing .Current .Wmdmg r.-

. iagsiteipg Camuiativeiy wanna, arida third `e'urreiit .from'uthe l.( zontrolled circuit, anenergizing pressure winding subiect to tliepressiire-of "such circuit, these two windeneifgfiz'in y winding of higlhresi'stance coinlparedvt'it l.the first energizing/'winding and differentially wound Lwith. respect to the aforesid windings; and a' switch operablev by the electro-magnet an'dserving, when' unactuated by the magnet, to open the controlled circuit and exclude the third winding' from circuit relation with the first twowindings and when actuated by the magnet -to close the controlled circuitand bring the third winding in shunt of the generator by way of the second winding.

'5. An electric current controlling device and anA electric circuit controlled thereby, which circuit has a current supplying generator, said device includingan electro-inagiiet having an energizing current winding receivingcurrent fromvthe controlled circuit,

an energizing pressure winding subject to 8U .the pressure of such circuit, these two windv ingsbeing cumulatively wound, and a third energizing winding differentially wound with respect to the aforesaid windings; and

a switch operable by the electro-inagnet and serving, when unactuated by the magnet, to open the controlled circuit and exclude the' third winding from circuit relation with the first two windings and when actuated by the magnet to close the controlled circuit and bring the third winding in shunt of the generator byway of the second winding.

6. An electriccurrent controlling device and an electric circuit controlled thereby, which circuit has a current supplying gencrater, said device including an electro-magnet having a swinging armature bridging the gap between two spaced apart portions .of the magnetic circuit of the magnet and swingingly mounted between its ends at one i of said magnetic circuit portions to"4 form therewith-'shunt related flux paths each serially relatedwith the fiux path furnished by the other magnetic circuit portion and the remaining portion of t-he armature, a current winding supplied with current from said current supplying generator, and, a pressure winding receiving pressure from said current supplying generator, and a switch operable bythe armature of the elecat'or, said device including an electrogrnagnet having an energizing current winding receiving current from the controlled circuit', an energizing pressure winding subiect to the pressure of such circuit, these two wind-A ingsbeingcumulatively wound, and a third energizing winding of' high'resistance comy paredwit i the first energizing winding and differentially wound with respect toV the aforesaid windings; and a switch having a contact yactuated by the magnet and serially inthe controlled circuit, a normal followu'p contact engaging the vfirst contact and by` which follow-up contact the second winding is includedin shunt of the generator, and an alternate contact serially in the controlled circuit `and engaged by the rstcontact before the first contact leaves its normal follow-up contact, the first two lcontacts having circuit association causing them, by their engagement, to shunt the third winding from the remaining windings and by their separation to bring the third winding inshunt of the generator, While the latter two contacts, by their'engagement, serve to establish the controlled circuit.

8. An elec-tric current controlling device and an electric circuit controlled thereby, which circuit has a current supplying generator, said device including an electro-magnet having an energizing current winding receiving current from the controlled circuit, anV energizing pressure winding 4subject to the pressure of such circuit, these two windings being cumulatively wound, and a third energizing winding di'erentially wound with respect to the aforesaid windings; and a switch having a contact actuated by, the magnet and serially in the controlled circuit, a normal follow-up contact engaging the first contact and by which follow-up contact the second winding is included in shunt of the generator, and an alternate contact serially in the controlled circuit and engaged by the first contactl before thefirst contact leaves its normal f ollowup contact, the first two contacts having circuit association caus ing them, by their engagement, to shunt the third winding from the remaining windings and by their separation to bring the third winding in shunt of the generator, while the latter two contacts, by vtheir engagement, serve to establish the controlled circuit.

9. 'An electric current controlling device and an electriccircuit controlled thereby,

which circuit has a current suplplying generator, said device includingan e ectro-magnet having an'energizing current 'winding rev ceiving current from the controlled circuit, and a'n energizing pressure winding subject to the pressure of such circuit, these two windings being cumulatively wound; a resistance that is high compared with the first aforesaid winding; and a switch having a contact actuated by the magnet and serially in the controlled circuit, a normal follow-up contact engaging the rst contact and by which follow-up contact the second winding is included in shunt of the generator, and an alternate Contact,seriallyA in the controlled circuit and engagedvby the first contact before the first contact leaves its normal follow-up contact, the rsttwo-contacts having circuit association causing them, by their engagement, to shunt the resistance from the windings and by their separation to include the resistance in series with the second wind-f. ing and in shunt ofthe generator, while thev latter two contacts, by their engagement,

serve to establish thecontrolled circuit.

nioaeao 10. An electric current controlling device and an electric circuit controlled thereby, which circuit has a current supplying generator, said device including an electro-magnet having an energizing current winding receiving current from the controlled circuit,

an ener izinr ressure winding sub'ect to D 23 the pressure'of such circuit, thesetwo windings being cumulatively wound, and a third energizing winding of high resistance compared with the first energizing winding and differentiallywound with respect i' to the aforesaid windings; and a switch operable by the electro-magnet and serving, when unactuated by the magnet, to o en the controlled circuit and exclude the t ird winding from circuit relation with the rst two windings and when actuated by the magnet-to close the controlled circuit and bring the ihird winding in shunt of the generator.

1l. An electric current controlling device and an electric circuit controlled thereby, which circuit has a current supplying generator, said device including an electro-magnet having an energizing current winding receiving current from the controlled circuit, an yenergizing pressure winding subject to the pressure of such'circuit, these two windings being cumulatively wound, and a third energizing winding di'erentially wound with respect to the aforesaid windings; and a switch operable by the electro"- magnet andserving, when unactuated by the magnet, to open the controlled circuit and exclude the third winding from circuit relation with the rst two windings and when actuated by the magnet to close the controlled circuit and bring the third winding` ics said current supplying generator; and laV switch operable bythe armature of the. electro-magnet and` in' controlling relation to said circuit.

t 13. An electric current controlling device and an' electric circuit controlled thereby,

which circuit -has`-a current supplying generator, said device including an electro-'magnet having an energizing current winding receiving current from the controlled circuit, and an energizing pressure winding subject to the pressure of such circuit, these two /windings being cumulatively wound; a re-- sistance that is high compared with the first aforesaid winding; and a switch vhaving a contact actuated by the magnet and serially in the controlled circuit, a normal follow-up contact engaging the first contact and by which follow-up contact the second Winding is included in shunt of the generator, and an alternate contact serially in the controlled circuit and engaged by the first contact before the first contact leaves its norma-l follow-up contact, thefirst two contacts having circuit association causing them,iby their engagement, to shunt the resistance and by their separation to include the resistance in series with the first Winding, While the latter two contacts, by their engagement, serve to establish the controlled circuit.

' 14. An electric current controlling device erator, said device including an electro-magnet having a swinging armature bridging the gap between two spaced apart portions of the magnetic swingingly mounted between its ends at one of said magnet-ic circuit portions to form therewith shunt related fiuX paths each serially related with the flux path furnished by the other magnetic circuit portion and the remaining portion of the armature, and a current winding supplied with current from said current supplying generator; and a switch operable by the arma-tur" of the electro-magnet and in controlling relation to said circuit.

In witness whereot I hereunto Vsubscribe my name.

ALBERT E. BERDON. Witnesses y A. J. VEBER,

E. C. BROMMER.

cijrcuit of the magnet and o

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