US824756A - System of alternating-current-motor control. - Google Patents

Description

YPATENTEEJULY 3, 1906.

7 1 m; I SYSTEM OF ALTEB-HATING CURRENT MOTOR CONTROL.

APPL'IOA'I-IOI-ITHZED IAB.10 ,1905.

' at or near the various TEDS AT S P T N O E 'auens'r some; or YONKERS. NEW YORK; 'As'sieNoR-.roorisjnnavA'ron COMPANY; OF-EAST oRAneE, new JERSEY; A GQRPORA- TION or NEw J RsEY.- 4

"SYSTEM oF ALTERN TiNs-cuRREnfi-Morora coursed- To all whom may} concern):

Be it known that I, AUGUST SUNDH, a citize'n of the United States, residing at Yonkers, in thecounty of VVestchester and State of New York, have invented certain new and useful Improvements in Systems of Alternating-Current Motor Gontrol, of which the following is a specification. Y

My invention relates to a system of alternating-current-rnotor control, and more particularly to an automatic push-button-controlling system as applied to the operation of electric e eva-tors. H

The object of thepresent invention is t provide a sim 1e and positive controllin device which w 1 overcome the manyfdifi iculties met with in alternating-current systems in use at the present time.

' The accompanying drawing shows the application of In invention to an elevator systerm for three oors operated by push-buttons and is moreor less diagrammatic.incharacter and illustrates a threephase power-circuit and sin le-phase operating-circuits.

The eliaracters a, b, and cdesignate a threewire tWo-phase-current supply.

is a main-line switch, and is a threepole switch.

and designate motor starting and reversing switches. Y

40 represents an alternating-current hoisting-motor, and slip-rings 'on the rotorshaft.

- 5O designates the releasing-magnet, which operates a friction-brake.

is a resistance connected through brushes to the rotonwinding.

and are the accelerating-switches which '0 erate this short circuit or cut out more or ess of the three-phase star-connected'resistance 60.

is a self-holding safety-magnet, and 9.0a

directly under which are five rings compris ing the floor-controller. These five rings are rigidly mounted on the same shaft l 6,'which is positively driven by some moving part of the hoisting-machine.

1, 2,1'ind 3 designate ush-buttons located cor-landings, and 1, 2 and 3 arethe landing-door contacts.

Specification of Letters Patent. Application 111 4 llarch illl, 190s. serialNo. 249.430.

Patented uly 3, recs;

4 represents a small slack cable switch.

7 designates a' junctionebox, preferably placed in the center of the shaft 5 is the elevator-car, which hasits side out away'in order to showthe push-buttons 12,

to1i9.

.6 6 are hoistin -cables carrying thecar 5.

13, and 614, the gatecontact 8, and safety-but-' The light blac lines represent the operating-circ'uits, while the heavy black lines represent the main-line and motor circuits.

g Inalternating-current controlling systems in use at the present tinieiiliere'is uncertainty and unreliabilityof roperoperation,cou led with a complicated? electrical circuit inc uding a multitude ofwires. It is therefore extremely difi'icult tokeep the system in proper Working order. My invent on; does away with the complicated is stern-of; wiring to a great extent and-at t esame time can be adapted to an alternating current of single or multi phase without any radical change in the controlling ap aratus. I

Generally spea 'ng, the operation of my invention may be pointed out as follows: On

pushing one of the operating-buttons a circuit iscompleted through acorresponding floor-relay,which operates to close a circuit through one of the motor-starting switches.

- At the same time switchesare electrically operated to prevent anyinterference from other possible circuits and to insure a correct operation of the system. The motor is set in motion when a circuit is established by one of the two reversing-switches 20 and 30, a friction-brake being released as soon as the motor receives current. Directly the motor has started .or very shortly thereafter switches,

influenced by the drop of potential in the rotor win'dings as the same accelerates, cut out or short-clrcult in consecutive steps portions gradual acceleration from tate f will be applied and the hoistmg macl'ine brought to rest ready for the next operation:

' In order to more fully describe the opera;

. v Z'rest to normal full speed. The circxiitilrfough the the floor-controller .when the e evator-c'ar IOO tion of my system and at the same time-to i show clearly the function of each of the sev- I fixed contacts 21 will be necessary to operate either'th switch shaft.'

the resistance 60 at the point (1, also to the fixed contacts 21 and '22, respective connectedto the supply-mains a, b, and c.

eral parts,'it will be supposed that there is 1 poweron the two-phase or threephase sup-' ply -main's a, b, and c, and the manually-operable switches and are closed, as shown in the drawing. This will connect the wires 17, 18, and 19 tothe supply-mains a, b, and c and cause them to become charged. The wire 17 is connected directly to the two middle terminals of the stator-winding of the motor 40 at the terminal block 29. The wire 18 is connected tov two contacts 34 and 23 onthe reversing-switches 30 and 20, respectively. The wire 19 is connected ,to the contacts 33" and 24 on these same switches. The switches 20 and are of similar construction, so a l description of one will apply equally as well to the other. The switch 20, for example, comprises a framework carried on a magnetplunger 28. -At-the upper ends of this framework, but insulated from it, aremounted the contacts 23'and 24, adapted to engage the and 22, respectivel said fixed contacts being direotl above an in the path of travel of the mova l e-contacts. The contact 25 is in like manner attached, to. the framework of the switch 20 and when the switch is in its do ward position rests upon and makes contact with the fixed contact 26.

Whenever the core framework and the on, the contacts23 and" 24 will engage the y, while the contact 25 will be raised out of, engagement with the fixed contact 26. 1

In'order to trace the circuit to the motor, it

20 or 30. Let it be assumed that the switch 20 has been operated so as to be in its upward or closed position. The contact 23 will now engage contact 21 and the contact 24 will engage 22. This will establish a connection between the wires 18 and 39 and also between 19 and 41'; The motor will now be Atthe same time the brake-magnet will receive current,}.since it .is connected to the same wires which supply the motor with current and will be energized to release the brake. The brake being of any preferred construction employing a spring or its equivalentto apply the brake and having magnetic means to release the same, the motor'will now be free to start and will operate to raise or lower the, elevator-car, as the case may be. The rotor-winding has three taps or connections leading to the slip-rings on the rotor- Connection is made with-these rings by the brushes 42, 43, and 444 in a wellknown way. A wire connects brush 42 to contact 48. Brush 43 is-connect'edto e and 47, ,while brush 44 is connected to f and 46.

28 is sufiiciently energized by the magnet-coil-27x'to raise the contacts mounted there Intermediate points. of the resistance.

such as g, h, and 7care connected, respectively, to the 'contacts 57, 58, and 56 of the switch'70.

- The switches ,and are similar in construction and each comprises three fixed contactssuch as 58, 56, and 57directly under which are three movable contacts 59, which are connected to ether and are mounted pon, but insulate from, theplunger52. The p unger 52 is rigidly connected to the plunger 51 represents a magnet-coil so placed with regard to the plunger 52 that when fully energized it tends to raise the plungers52 and 53, together. with the contacts 59, which latter will engage the fixed contacts 58, 56, and 57, placed directl above them. The magnet-coil 54 is so p aced with respect to to draw t e plunger in .a downward direction.

The same description apply to the switch; 75, the magnet-coil 63 acting in opposition-to" the plun er 53 that whenen'er gized ittends the magnet-coil 62, which latter tends to" raise the three contacts 49into engagement with the three fixedcontacts 48, 46, -and'47., 55 and 61 are resistances of-=difierent values which check the currenttogtheir respective magnet-coils 54 and 63', the resistance-55 .be-

ing greater than theresistance 61.-

T e operation of the accelerating- switches 70 and 75 is as follows? Assoon as the stator or primary is connected to the two-phase or three-phase source of supply byfmeans ofithe 'reversmg-swit'ch 20 or 30' the two' m "netcoils 51 and 62, being connected'in paral el to each other, will be at once energized-, since their source it, and the magnet-coil 63, having the resistance 61 in. series with it, are in parallel to each other and are "connected to the motorbrushes42 and 44. The motor armature orv current and give starting torque. As soon as the rotor begins to revolve the induced voltage therein will,

drop proportionately to the speed, producing a proportional drop of potential across the magnet-coils 4 and 63, and consequently a loss power-lei downward pull will be exerted upon their respecti e plunger-s. As long as the primary oi the motor is connected to the of currentssupply is identical with that of. the stator-winding. The magnet; coil 54, having the resistance 55 in series with tential across these coils will be'proportion'al source ol 'currentsupply. and the voltage of' the supply remains constant the upwardovercomethat ofthe ma net-coil 54 and the contacts 59 will beraise J ntil they engage the three contacts fixed directly above. This is "due to the'tact' that the resistance 55 is greater than the resistance 61, and conse-' r5 'quently less current flows in the coil 54 than in the coil 63. This operation will short-circuit-aportion of the resistance in series with thesecondary winding, allowing the motor 1303855111116 auhigher speed. I zoyoltage in the secondary, owing to this ihcrease of speed, will drop stilhlower until finally the magnet-coil 62' overpowers the coil 63and raises the three contacts 49 into enga ement with the contacts 48', 46, and 47.

This lastoperation short-circuits the secondar- '3 or rotor-winding and the motor attains fuil speed. If the reversing-switch had been'operated instead of the switch 29, the

only difference would have been to inter- 0 change the connections leading to the out-' side terminals of the primary Win'dingof the motor. The wire-17 remaining connected to the, two inside terminals, this would cause the motor to revolvein an opposite direction.

'5 4 The operation of the push-buttons 1 2 3 ,,and.l2, 13, and 14 will now be explained. Starting at the point 64 where the. feed-wire ofiihe operating-circuit connects onto" the main linea and passing-through the limitswitches 65 and 66, which are normally closed, a circuit leads by wire 67 to one terminal of each of the magnets of the floor-re lays 11,22, and The wire 67 also leads to the contact 68, where the circuit is nor- 5 mally open. The other terminals of the floor- magnets 11, 22, and 33 are connected, respectively, to the Wires? 2, 71, arid 69. The wire 72- is normally open-eircuited at the push-buttons 1 and 12 andat the brush 73. 5o The wire 71 is open-eircuited at brush 7 land push-buttons 2 and I 13, and the wire 69 is open-circuited at brush 76 and push-bu ttons 3 and 14. Therefore in order to complete a circuit through any one of the floor-relays it 5 5 will be necessary to operate one of the pushbuttons.-

3 has been pushed, a circuit will be closed fromwire=67by way of magnet-coil 33, wire 69,- .through the button 3, and by 'wire- 77 to fiqone'terininal of the-inductive resistance or "impedance coil 80. The other terminal of the resistance 80 is connected to a fixed contact 78 of the non-interference switch 90. The inductiveresistance coil80,with its core The induced Assuming that the landing-button tense a 80, constitutes a compensating resistance for the hall-button circuit. This compensating resistance is so constructed as to be theelectcical equivalent of the non-interference re la 90, so that the current through a floorre ay will be substantially the same whether a car or hall button is operated.

The contact 78 is-normally connected by the contact-plate 79 to the fixed contact 81 i contacts 3", 2, and 1, the slack-cable switch '4, line-wire 86, to the-wire 17 and main-line lead I). On reviewing the circuit just traced it will be seen that the magnet-coil of the floor-relay 33 and the inductive resistance 80 are in series in a single-phase circuit across the mains d andb. The circuit to the reversing-switch coils 2.7 and 37 is normally 0 en at the floor-controller ringsmounted 'on t e motor-shaft 16. The magnetof the relay 33 will now be energized to raisefits core,

to which is connected the-insulated brush'7 6, this latter being connected to the'wire 69, but insulated from the rest of the relay-33.

The relays '11 and 22 are similarly constructed. At the same-time that relay 33 is energized the inductive resistance 80' is en'-' ergized and raises its plunger, which heretofore protruded but a short portionof its length, into the magnetic field setup by its coil. As the core or plunger of resistance 80 is raised less current flows in the circuit including said resistance 80 and the floor-relay 33,0wing to the increased inductive or choking effect produced by decreasing the magnetic reluctance of said coil 80. This core is so arranged that the movements thereof, and consequently the effect on the current, shall be substantially the same as the movements of the core 93 and the effect thereof on the currentfiowing'in the coil of the non-interference magnet. The upward movement of the core of the magnet of relay 33 'will cause the brush 76 to come into contact with the contact-ring 87. The ring 87, is connected IIO by wire to the contact-ring 88, and this is connected by wire 89 to coil 27 of reversingswitch 20. The operation of the floor-relay has caused a circuit to be completed through the reversing-switch coil 27 from wire .69 in parallel to the inductive-resistance coil 80, and this parallel circuit is in series with the magnet of floor-relay 33. As'soonf bS'the magnet 27 receivescurrent it will 'be-ie nere gized to raise its plunger 28 tostart the motor in such a direction as to raise the ele- A circuit comprising the limit-switches, the

floor-relay 33, the reversingswitch magnet 27, the safety-button 9, the gate-contact 8, door-contacts'3 2 1, and slack-cable switch 4, all in series across the supply-mains a and b, has been established. The elevator is now ascending at full speed and the five contactstrips on the floor-controller will all be re- I volving in a left-hand or counter-cldckwise up on the drawing.

direction, as indicated by the arrow marked arrives at the desired landing, in this case the third fioor since button 3 was operated,

' the contact-strip 87 of the floor-controller tact-strip 91.

will run off the brush 76 of the floor-relay 33, causing the circuit through the ma -net of reversing-switch to be broken, allowing the latter to drop its. plunger. The motor will then be stopped bythe application "of the brake. From the above it will be seen that as soon as the reversing-switch was 0&-

- erated it caused the circuit feeding the 1a ing-buttons 1, 2, and 3 to be broken, thus rendering any operation from these buttons to be of no effect so long as the reversingswitch 20 is in a osition to'start the motor.

The position of t e floor-controller, as showii on the drawing-,indicatsthat the elevatoris at the first 'or lowermost landing, making it impossible to operate the switoh30 at this time. If after the floor-controller has been revolved, as first described inconnection with the car going to the third floor, and the contact-strip 87 has been carried out of engagement with the brush 76 and the car has been brought to rest, the landing-button 1 were pressed, the floor-relay 11 would operate to cause the brush 73 to engage the con- This would cause a circuit to be estab ished as'before, onlyin this case the circuit would be completed through the wire 92 and magnet 37 of the reversing-switch 30 and the motor would bestarted to lower the elevatorcar, the car being brought to rest at the first floor when the contact-strip 91 runs off the brush 73, the reversing-switch 30 dropping to normal position. The contacts' v and 36 are separated by the upward movement of the switch 30, which produces a result similar to that produced when the switch 20 was operatedviz., breaking the circuit through the inductive resistance and the landing-button feed-wire 77. Since the operating-circuit includes the safety-bub ton 9, gate-contact 8, door-contacts 1, 2', and 3,-the slack-cable-and limit switches 4,

66, and 6 5,respectively, and a fuse 98 ineach side of the circuit, the operation of any As the elevator-car theu per end of each plunger is connected to a roc er-arrn pivoted at 91. one plunger rises the other will descend, and vice versa.

weight 92 will'alyvays assume its lower posi- ;tion whenthe magnet-coils of and .90 are The plunger 93 on account of the Therefore as I not energized. At the lower end of each of l the plungers 94 and 93 are contact-disks havlng asma 1 vertical movement a ainst the ten sion of the small springs shown ireotly above them. In the ath of travel of these contactdisks are fixed contacts 68, 96, 78, and 81- two for each switch. When the switches are in' their normal position, the contact-plate 79 ofswitch connects the'contacts 78 and 81 When the contact disk of together. SW1tch'85 is in itslower position, it connects the contacts. 68 and 96 together. The operation of the car-buttons is as follows: As before, the circuit may be traced from wire 64, leading by way of the limitswitches 65 and 66 and wire'67 to the terminals of the magnets of the floor-relays 11-, 22, and 33. Circuits 72, 71, and 69 lead from the relays 11, 22, and 33 to the car-buttons. On J pressing the button 14 a circuit is closed 'to wire" 97 and magnet of switch 90 and by wire -83 through the contacts of 9 8 3' 2 1', slackcable switch 4,to the main line 'b' throu h wire 17. The magnet of the floor-relay 33 Will be energizedand will .cause the brush 76 to engage the floor-controller stri 87, which wi complete a circuit through t e reversingswitch 20 to start the motor in the same manner as was done in the case described before when the landing-button was operated. The magnet of switch 90 when ener ized will operate to raisethe plunger 93 to isconnect the contacts 78 and 81, open-circuit the feed-wire to the landin -buttons, and thus prevent any interference should these buttons be manipulated. When the magnet 90 raises its plunger, the plunger 9.4 of the magnet-switch 85 will be forced downwardly until the contact- 'disk 95 will engage the contacts 68 and 96. This will at once cause the magnet of switch 85 to be energized to hold down its core. The magnet-switch 85 receives current at nearly the full-line potential across the mains a; and b, the circult starting from main 0, being through 67 68 95 96, magnet of switch 85 lead 83, button 9, gate-contacts 8, 3, 2, an 1, and throughlead 86 to 17 and main b. It will therefore beseen that the switch 85 is a self-holding safety-switch. As soon as the car reaches the third-floor landing the floor-. controller will, as before, break the circuit supplying the reversing-switch '20. The

floor-relay 32 will also be denergized, as the button l4 was closed from 69 to 97 only at the beginning of the operation. The motor Wlll therefore come to rest. The circuit to the safety-magnet 85 will remain unbroken.

. the landing bilttons 1, "g2, and 3 wil have no effeet. As fl ecar-gate'fis opened, however, to allow theoperator to'get out from the car the circuitgtlirough themagnet 85 will be chin'er'y, makes an automatic operation possingle phase to simplify the wiring.

broken at the. gate-contact B, allowing the plunger-94 to rise, due to he weight 92. Then the contacts 7 8 an 8 will once more be connected by the disk'f79,making it again possible to operate; the car from the landin 'buttons after the doo i s'are all closed. Shoul d the car for some reason overrun its travel, the limitswitchsv will operate to open the circuit leading to the reversing-switches, which would cause the motor to come to rest. As an extra preventive for the car overrunning arms might be mounted u on the floor-controller shaft 16, which won d open the switch 15'or a manually-closed switch in the circuit 67 if the floor-controller should revolve past its normal travel. One arm would be opera tiveat the extreme upper limit and another arm at theextremelower limit.

' It has been shown how the various pushbuttons by, their operation cause the ener ization of corresponding floor-relays and ow thefloor-controller, which acts in conjunction with. the floor-relays and the hoisting masible., The car always goes to the desired floor and stops there automatically whether operated from the landing or from the car buttons The car can be stopped atany point in its'travel by merely pressing the button'9,which normally closes the circuit in which .it is placed, the operating-circuit in every case being completed through said butt'on 9.

The system described is well ada ted to an alternating cm'rent circuit of anyp ase. The operating-magnets may be placed across a suitable pair of leads of the multiphase circuit, the only requisite being that the current passing through the magnets shall be In the three-wire two-phase motor-circuit, as shown in the drawing, or in a three-phase motorcircuitthe operating-magnets of the pushbutton system may be placed across any two leads. The operating-magnets are shown placed across the mains a and b; but it is obvious that they could be placed across mains a and c or across mains b and c.

I do not herein claim thespecific means for accelerating the motor, as this specifically is the invention of David l Lindquist and is described and claimed in an application copending herewith. The brake-magnet shown connected to my electric elevator-controlling system may be such as disclosed in the patent to Lindquist, No. 744,773, granted November 24, 1903, in which particular attention is directed to Fi VVithout limiting mysel to the precise construction of details herein disclosed, but reserving the rightto make such changes as fall within the s irit and sec e of m invention P F Y what I claim as new, anr Letters Patent, is p 1. The combination with an alternating current motor, of controlling means therefor, and an electrores 'onsive device arranged to control a singleep ase circuit to said motorcontrolling means.

2L The'combination with an alternatingcurrent motor, of controllin means therefor, and an electroresponsive (evice connected in a single-phase circuit to mains of said motor, said electrore'sponsive device being so constructed and arranged as to control "a circuit'to said motor controlling meansr 3. The combination 'with'an alternatingcurrent motor, of motor-controllingmeans, circuits and connections of an automatic desire to secure by push-button-controlled elevator system comand connections of an automatic push-but ton-controlled elevator system comprising single-phase magnets correspohdin to the various floors, and a floor-control er; said circuits and connections being so constructed and arranged that when one of said magnets is energized a-single-phase circuit shall be closed to' said motor-controlling means.

5. The combination witha multiphase motor, of motor-controlling means, and circuits and connections of an automatic push- .button-controlled elevator system compris ing a sin le-phase magnet arranged to be operated om the car to prevent interference from the landing push-buttons.

6. The combination with a multiphase motor, of motor-controlling means, and circuits and connections of an automatic pushbutton-controlled. elevator system arranged to be energized by single-phase current, said circuits and connectiops comprising a nonr,-- I interference magnet controlled from the car and a holding-magnetlcontrolled by said noninterference magnet.

7. The combination with an alternatingcurrent motor, of motor-controlling means, circuits and connections of an automatic push-button-controlled elevator system comprising asingle-phase non-interference magnot controlled from the car, a compensating rent-motor controlling means,

and connections so arranged inductive resistance controlled from a land:

mg, and floor-relays controlled from either, said parts being so constructed and arranged that whether a carer hall button is 0 erated the current through a. floor-relay stall be substantially the same. i

8. The combination with alternating-cura relay for automatically controlling a circuit to said motor-controlling means, an inductive resistance in a normally open circuit with said relay, means for manually closing the circuit between said relay and inductive resist? ance, and means for breaking the circuit to said inductive resistance upon the operation of said motor-controlling means.

9. The combinationwith alternating-current-motor controlling means, of an electroresponsivejdevice for controlling a circuit to said motor-controlling means, an impedancecoil in circuit with said electroresponsive device, a movable core for said impedance-coil, and. means for impedance-ct)il as soon as the normal relation of parts of said motor-controlling meansis changed. 1

It). The combination with an alternatingcurrent motor, of motor-controlling means therefor, an 'electroresponsive device arranged to control a eirc-uitto said controlling means, a choke-coil in circuit with said electroresppnsive device, and electric circuits that upon the operation of the motor-controlling means the circuit to said choke-coil is broken.

H. The combination with an alternatingcurrcnt motor, of motor-controlling means therei' or, a relay arranged to control a circuit to said motor-controlling means, achoke-coil in a circuit in parallel with said relay, a mova ble core for said choke-coil, and means i or interrupting a circuit tosaid choke-coil after the circuit to said tloor-eontrolling means has been established.

12. The combination of a multiphase motor, with a-source. of alternating-current supply comprising main lines, tnotor-controlling means. an electroresponsive device for controlling a circuit to said controlling means, an inductive resistance in circuit with said electroresponsive device, a circuit. including said electrores mnsivc device and. said' in ductivc resistance and placed across two of the mains of the source of supply.

13. The combination of a multiphase motor, with a source interrupting a circuit to said of alternating-currcnt sup -pedance-coil in ply of three or more phases, said source comprising main lines: motorecontrolling means, circuit-controlling means for controlling' a circuit tosaid motor-cont rolling means, an inductive resist ance in circuit with said circuit closing meaus,and a circuit. including said inductive resistance, connected across a pair of said mains.

14. The combination with a three-phase motor, of a source of alternating-current supply comprising main lines; means comprising a.single-phase magnet for controlling said motor; asingle-phase relay-magnet, means operated thereby for controlling a circuit ,to said Inotor-controllin" magnet, an impedance-coil in circuit with said relay-magnet. a movable core for said impedance-coil, and a circuit including-the s'aid magnets and impedance-coil anu arranged to be connected across any two of said main lines.

15; The combination with a twophase motor, of a source of alterlrating-current suphnes: means coniply comprising three main prising a single-phase magnet" for cont rolling said motor; a single-phase relaymagnet, means operated thereby for controlling a circuit to said motor-control]ing magnet, an imcircuit with said relay-magnet, a movable core for said impedan -e-coil,

. and a circuit including the said magnets and impedance-coil and arranged to be connected across any two of said main lines.

16. The combination with amultiphase motor, of a source of alternating-current supply comprising main lines; an electromagnetic motor-controlling means, a relay, a variable inductive resistance in. circuit. \vith'said relay, and circuits and connections connected across two of. said main lines and. so arranged that when-the circuitto said relay and inductivs resistance is closed a circuit is antomatically closed to said electromagnetic motor-controlling means after which the. circuit to said inductive resistance is automatically interrupt-ed.

17. The combination with a car and its metor, of stations, motor-ctmtrolling means, an electroresponsive device for controlling a circuit to said motor-ctmtrolling means, an inductive resistance in a normally open circuit, and means at said stations for closing a circuit between said electroresponsive device and said inductive resistance.

18. The combination with an elevator-car and its motor, of nuitor-controlling means, a relay, a variable inductive resistance. means at the landings to close a circuit between said relay and inductive resistance wlu-reby a circuit is closed to the motor-controlling means, and means operatingin con junct ion with said motor-control]ing means to then break the circuit through said inductive resistance and circuit-closing means at the landing 19. The combination with an elevator-car and its motor. of motor-controlling means, a relay. electric circuits and connections and push-buttons to automatically ontrol the travel of said car, an inductive resistance in anormally open circuit with the pushbuttons at the various landings, whereby when .a circuit is closed between said inductive re- 'which the circuit to said inductive resistance and landing push-buttons is automatically interru ted at said motor-controlling means.

20. he combination with an elevator-car. and its motor, of motor-controlling means, a push-button at each landing, push-buttons in the carcorres ondingto the landing pushbuttons, "an ind iictive resistance connected vto.;tlie landin 'pus'li-buttonsrelays connected to the lan ing push-buttons and car pushbuttons, and electric circuits andj coiinections so arranged that when a landing push-button is operated a circuit is closed between said iiiductive resistance and one of said relays whereas ifa car push-button is operateda circuit is closed to onl 1 one of said relays,

' said relay closing a circuitto said motor-controlling means after which the circuit to said landing push-button and inductive resistance is interrupted.

21., The combination with analternatingcurrent motor, of an elevator-car, electric circuits and connections of an automatic push-butt0n-controlled elevator system comprising a motor-controlling means, a relay for controlling a circuit to said motor-controlling means, 'an impedance-coil, a'movableand connections of an automatic push-button-controlled elevator system connected across two of said main lines and comprising motor-controlling means, a floor-controller, a relay for closing a circuit through said;floorcontroller to said motor-controlling means,

means for'controlling said relay from the car or from a landing, a variable inductive resist ance connected in circuit with said relay when said landing-controlling means is operated,

and means for interrupting the circuit to said inductive resistance after said relay has op-- erated.

23. The combination witha two-phase mo tor and three"'supply-mains therefor, of an electric car arranged to be operatedthereby, electric circuits'and connections of an automatic push-button-controlled elevator system connected across any two of-said main lines and comprising motorcontrolling means, relays for closing circuits to said motorcontrolling means, a variable inductive resistance, push-buttons one at each landing for closing circuits between said relays and inductiveresistance, and means for rendering said landing push-buttons inoperative prior to the starting of the sa id motor.

24. The combination with a motor and motor-controlliiig 'iiieaiis, of an 'cle'ctroresponsi ve device for closing a circuit to said niotor controlling means, a variable inductive resistance, a switch for closing a circuit between said variable resistance and said electrorespons ive device, means connected with said inotorcontrolling means for,interrup ting the cir- -'cuit to said inductive rcsista'nceand ailditioii'al means for interrupting said, l;ist.-inen tioncd circuit and maintaining the. same in terrupted until after-the motor has stopped,

25, The combination with a motor and motor-controlling ,nieaiis, vmeans for, controlling a circuitto said motor-controllingmeans,

an inductive resistance, a switch for closing a" circuit between said circuit-closing means and said inductive resistance means for illterriiptingthe circuit to said switch and 'closing a circuitto render said switch inoperative until said last-mentioned circuit is in te'r rupted;

26 The combination with an elevator-car and its motor, of. electric circuits andfconnections of an automatic push-buttoii-controlled elevator syste n comprising inotor-contr'oL' ling-means, means-controlled from the land-r:

ings or from the car to close circuits to said motoncontrolling [.nieaiis, means operated from the car fi or rendering the landingsbuttons inoperative, a loCkingmircuit-closed by said last-inentionedme'ans so a-i'ranged that 4 i said landing-but ns remaininoperative until said locking-circuit is interruptedi 27, An automatic push-buttonscontrolled IOO elevator system, comprising a'eiir' and its mo- I tor, means for controlling saidmotor, means controlled from any landing or from sa d car for closing a circuit to, said motorecontrolling means, an electromagnetic switch for inter rupting the circuit to the laddingrbuttons to render them inoperative, a second electromagnetic switch arranged to close a locking-- circuit, means connecting the two switches for maintaining said landing-buttons inoperative untilthe locking-circuit is interrupted.

28. An automatic push-buttomeontrolled elevator system comprising a car and its motor, motor-controlling means, means controlled from said car or any landingfor operating said motor-controlling means, a switch for interrupting the circuit to the landingbuttons, a solenoid connected-to the buttons inthe car, a core for said solenoid said core being connected to said switch, a locking-circuit, a second switch and a second solenoid both in said locking-circuit, a second core ccnncctci'l to said second switch and mechanically connected to the first core, whereby when the ear push-button is operated the landing push-buttons are rendered inoperative and maintained thus by the closing. of the. locking-circuit until said locking-circuit is interrupt-(Kl. 29. .[ii an automatic piisli-l utton-con- IIO nect-ions so arranged that when one'coreis in its lower position the other is in its upper position thus opening the circuit to the landing- 3 buttons and closing the locking-circuit when a car-button is operated, and means for returning said switches to normal when the locking-circuit is interrupted.

30. An automatic pushsbutton-controlled elevator system compri'sin' a push-button for each floor or station, push-buttons for the car, motor-controlling means and electric circuits and connections therefor, a switch arranged to be operated as the motor is started to render the floor push-buttons inoperative during the operation of the motor, a second switch in the circuit to the floor push-buttons, electromagnetic means controlled by a car push-buttyn. for opening said second switch, a locking-circuit, means controlled by said electromagnetic means for closing said locking-circuit and means for holding said last-nientioned circuit closed, so arranged .as to prevent the starting of the m0- tor after being stopped until said locking-circuit has been interrupted at a predetermined point.

31. An automatic push-button-controlled elevator system comprising, an alternatingcurrent motor, circuits and connections including single-phase magnets for controlling the operation of said motor, a variable inductive resistance, manual means for closing a ircuit through said inductive resistance, au-

tomatic means controlled from the car for lnt-errup ting the circuit to said manual means and inductive resistance, and means controlled by said automatic means For holding the said circuit to the manual means inter-- rupted until after the car has come to rest.

In witness'whereol' .l have signed my name in the presence of two subscribing witnesses.

AUGUST SUNDH.

Witnesses:

nucmas M. NISSEN, EnNEs'r W. MAnsnALL;

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