US980302A - Controlling device for alternating-current motors. - Google Patents

Description

D. L. LINDQUIST. CONTROLLING 11mm: FOB ALTERNATING. CURRENT MOTORS.

WAPPLIOAVTION 111.21; In as, 1905. 980,302.

Patented Jam 3, 1911.

$ L I 2 SHEETS-SHEET 1.

WITNESSES: M INVENTQR ATTORNEY! D. L. LINDQUIST. CONTROLLING 11111 101. r011 ALTERNATING CURRENT MOTORS.

' k 7 APPLICATION FILED 11411 26, 1905. 980,302.

I .Patgnted Jan. 3,1911. I {e0 2 SHEETS-SHEET WITNESSES: v ENVENTOR ATTOR N EYS i F TED STATES PATENT OFFICE DAVID LEONARD LINDQUIST, OF YONKERS, NEW YORK, ASSIGNOR TO OTIS ELEVATOR COMPANY, OF JERSEY Ci'IY, NEW JERSEY, A CORPORATION OF NEW JERSEY.

CONTROLLING DEVICE FOR ALTEBNATING-CURRENT MOTORS.

Patented Jan. 3, 1911.

To all wlwm it may concern:

Be it known that I, DAVID L. LINo UIsr, a subject of the King of Sweden and Norway, residing at Yonkers, in the county of Vestchester and State of New York, United States of. America, have invented a new and useful Improvement in Controlling Devices for Alternating-Current Motors, of which the following. is a specification.

My invention relates to means for controlling electric motors of the induction type which are adapted to be operated by singlephaseor polyphase currents.

The object of my invention is the pro vision of means for controlling alternating current motors of the induction type inde pendently of-predeter'mined voltages on the ines by which the motor is arranged to be supplied with current. .To accomplish this I provide an electrical device adapted to be fed from the primary circuit and place it in co-acting relation with an additional electrical device fed from the secondary circuit so that upon a variation in the primary voltage the effective operation of t ese devices shall not be sub ect -to change when not desired. i

One embodiment of my invention is disclosed hereinafter and is an improvement in my Patent,'No. 733,550, granted July 14, 1903. i

I do not limit myself to the details of construction and arrangement of parts as herein disclosed, as many changes may be made without departing from the spirit and scope of my invention. I therefore desire that 7 my claims may be construed; broadly.

Referring to the accompanying drawings,"

Figure 1 is a diagrammatic view showing my apparatus applied to a two-phase motor which is arranged to be supplied with two or three-phase current; Fig. 2 is a diagram-j matic view showing a slight m0d1ficat1on of Fig. 1; Fig. 3 shows an arrangement of apparatus whereby I carry out the object of my invention by means of magnets of different strengths and also shows contacts for interrupting a circuit through certain controlling electro-magnets; Fig. 4 is another modification. showing the controlling (3011s in circuit with the secondaryof the motor,

- in'series with each other, and alsoshowing ,contacts toestablish and interrupt certain "circuits.

Similar reference numbers and characters indicate like parts throughout the drawings. Referring to Fig. l, M designates a motor of the induction type. It is here shown as a two-phase motor, the main 17 being connected to the inside terminals at the top of the motor and the mains 39 and 41 to the outside terminals. The current supplied to the motor through the mains 17, 39 and 41 may be two-phase or three-phase.

To the motor secondary, by means of the slip rings S and brushes 42, 43 and 44 are connected the resistances R, here shown as star-connected. To the terminals (1, c and f are connected the fixed contacts I), b and b, respectively. To the intermediate points g, h and k are connected the fixed contacts a, a" and a i Under the fixed contacts a, a" and a are suitably mounted the movable contacts 59 electrically connected together and adapted to make contact with and electrically connect the fixed contacts a, a", a. Under .the contacts I), b", b are similarly mount- B are energized the coil B tends to pull core 2 downwardly and consequently the contacts 59, while the coil A tends to force the sameu'pwardly. The switch 75 is similarly arranged to act in a similar manner but comes into operation to move the com tacts 49 upwardly later than the switch 70 by reason of the resistance'r and r", the, resistance r being greater than the resistance 'r.

The coils A, A. are connected in parallel across any two of the primary mains to the motor. In Fig. 1 these coils are shown con-' nected from the points 7 and 8 b means ofcircuits 5'af1d 6, respectively, to t e primary mains 17 and 41. The coils B, B" are also connected in parallel and to any two circuits leading from the brushes connected to the rotor or secondary of the motor. Fig; 1

shows the coils B, B connected through the wires 9 and 10 to the terminals e and d, respectively. t ough the current in the primary may be twoor, three-phase and that in the secondary three-phase, the coils A, A, B and B"i are so connected that the current therein will always be single-phase. This arran ement is for the purpose not only .of simp ifying the wiring but .to automatically control the starting of the motor and maintain the same at substantially full speed independently of the voltage'in the primary. That is to say when the circuits to the motor are closed from a source of supply of alternating current, the relation 'betweenthe primary and secondar voltage is' constant, and therefore the IBlfitlOD. between the voltages applied to the coils is constant, so that if a drop of voltage should occur in the primary mains the operativeness of the switches 70 and 75 to properly start the motor will not be impaired within certain limits. This constant relation of voltages also holds true while the motor is running, so that should the main line voltage drop somewhat then the switches 70 and 75 will be held in closed position and not interfere with the running of'the motor.

In starting the motor the o eration is as follows: When the primary circuit is first closed from the source of supply the secondary voltage willbe at its maxlmum and conse uently the current flowing through the C01 s B, B will be at a maximum. The coils B, B, having greater strength than the coils A, A which are energized from two of 'theprimary mains, will hold the switches 70 and 7 5 in their lower, positions. So long as the voltage of the primary mains remains constant the current through the coils A" and A" and consequently the strength or pulling force on the cores Iand 3 remains constant. But'as the rotor speeds up the secondary voltage gradually drops causing less and less current to flow to the coils B, B ,untiI finally the coil A over comes the coil B and moves the contacts 59 into engagement with the contacts a, a",

0" thus cutting out part of the resistances R.

The resistance 1' being greater than the resistance r" more current will always flow in the coil B than in the coil B. The coil A will therefore overcome the coil, B later to cause the contacts 49 to engage the contacts 6', b, b'. That is, the motor runs to full slow speed and then a partofthe resistance. is cut out. which causes the motor to run at a greater speed. In doing so the secondary voltage gradually drops until themotor has attained a predetermined speed when all the remainder of the resistances R are cut out by the switch 75. This causes the motor to run up to full speed.

.sNOW since .the strength of the coilsA', A, B, B varies directlyfas the' current flow therein and the current varies directly It is therefore obvious that -5 and 9 forA.

as the voltage applied to said'coils, any drop l these coils would exert less force to pull" down the-cores 2 and 4. The strength of the coils A, A is similarly decreased causing a less upward pulling force .to be exerted by them, so thatthe resultant action of the switches and remains the same and the contacts are held closed.

In Fig. 2 I have shown motor controllingapparatus-similar to that shown in Fig. 1

but the coils connected to the primary are connected across different phases but still remain single-phase coils; so also are the coils which are connected to thesecondary connected across separate phases but remain single-phase coils. In this arrangement the current from the .phases is more evenly distributed which may be an advantage in some cases in the operation of the motor. either Fig. 1 or Fig. 2 one or more series of contacts may be added and the resistances R correspondingly increased so that the accelerating action may be as gradual as desired.

Referring to Fig. 2 the coils A, A, A are seen'to be connected :to separate phases of a three-phase circuit by means of the circuits 6 and 9 for A, 5 and 6 for-A" and The coils B, B, B are shown similarly connected to the'secondary or rotor circuit by means of-the circuits 15 V and 16 for B. 15 and 18 for B" and 16 and the motor to accelerate in speed up to full speed. First the coil B weakens after the circuit'to themotor is closed until overcome by coil A when the disk D connects a,-a, a leading to the points 9', h, k, short-circuitingone of the resistances R, here shown as the central sistance. The disks are insulated from the the disk D .has been raised and the motor ortion of a star-connected re-- solenoid cores by the insulation19. After point the disk'D, and finally in ajsimilar resistances speed has been increased to a predetermined" l 'to Fi 1.

In Fig. 3 I rangement of a ciple of operation 1s the same as that alproximity magnets, name parallel and the motor at liberty to run up to full pe a v The coils B", B-,'and B may be made of different strengths so that they will release their cores successively to effect astepby-step. cutting out.of the sectional res stance It.

The rinciple of operation of the arrange 'ment sliown' in Fi 2 is-substant-ially the same as that alrea y explained in reference paratus although the prinin connection with Figs.

ready described 1 and 2. In place cores shown in Figs. 1 and 2 I pivot levers L, L", L at 21, 21', 21" respectively, in to electro-magnets having poles of difierent lengths so that said magnets may have a maximum efiect on said levers which are of magnetizable material and therefore serve asarm'atures. Three of these 1 A, A" and A are connected in para leland across two of the primarymains. Fig. 3 shows these three magnets connected to mains 17 and 41 by wires 5 and 6. The other three magnets, namely, B B and B are connected in V cuits, as across the brushes 43 and 44 by so magnets B, B", B" which are fed by ourrent from wires 26, 33 and '27, 34.

In circuit with the magnets A and A are the contacts. 24 and 25 which are normally closed but when separated break the circuit tothe magnets A and A, the circuit to the magnet A however, always remains intact.

' As in Fig. 1, resistances r',r, r are shown in Fig. 3 in series with the ma e ts B, B", B, respectively, the value 0 said resistances gradually" diminishing in the order named, so that the current flowing through the magnets B, B, B for any given voltage across the circuits 26, and 27 may be least in B and most in B.

When the primary circuit is closed at switch 20, the parts will take the shown and the armatures L, L, L.

will

be held in their normal positions bythe the secondary. At the same time the magnets A,;A", A are exerting a pulling force to move the armatures in the PP W the rotor the'voltage in the secondary drops until magnet A I overcomes magnet B" and the armature L is moved tocause the contacts 59 to engage with the contacts a, a

a". As the motor speeds up the armature t L acts in the same manner to. close its contacts and finally armature L v is operated after which the "m re L" is moved by the magnet A"! have shown a different arof the verticall movable across two of the secondary cir-' s ring 38; to close. c osure of these contacts closes the circuit justtraced through the coil A also; that positions contacts (1 p v f all three coils A, A, A in parallel but when all of theresistances are finally shorts circuited to allow the motor to attain full speed the contacts d are closed direction. Due to the rotation 0 motor attains full speed. It should benoted, however, that when'the the contacts 24'and 25 are separa'tedand the circuit to the magnets A, A therefore broken. The levers L, L return. to their normal posltions but armature L is held in its contact closin position by the magnet A which is always n circuit with two mains of the primary. The resistance of the circuit-5, 6 being thus increased less current is necessary to be shunted away from the primary which may serve to allow the motor to run more evenly where all the magnets connected to the primary are connected across only twoof the mains.

Fig. 4 shows another modification of my invention. The motor is here shown more diagrammatically, 51 designating the stator winding and 53 the rotor winding. The

coils connected to the rotor are connected in series, whereas in the previous figures they were 1n each case connected in parallel. The coils A, A", A" oppose the coils B, B", B in their. act-ion as before, and as indicated by the arrows. The cores 35, 36 and 37are arranged to close contacts as already explained to cut out the resistances R and are shown su ported on springs 38, 45 and 46,respecti ve thus se aratingthe contacts d, d and d and c osing t with that of the spring 46.

The operation of the apparatus shown in- Flg. 4 is as follows: Assuming the switch.

20 closed to a source of three-phase current supply a circuit will be established through COll A from mainl to and through wire 4:7,coil A, wire 52, contact f'and that on spring 46, said spring, wire 4.8, to main 39.

'Until the motor has attained a predetermined speed, however, the coil B will exert a greater downward force than the coil A exerts in an upward direction on the core 35. IVhen, however, the motor has come to a certam'speed the core 35 overcomes coil B and the core 35 is moved upward allowing the 1s, the coils A, 'A'are connected in petal-1 lel. When the core 35 was moved upward the disk D and contacts co-acting them: with caused-apart of the resistances R to be short-circuited. The next is the cutting out of more of said resistances which is done by the ,disk

are then closed, which coil A, however,v

e contact f p the contaetsfd'Q The 11o D when moved upward. .The P ace to the contacts d, spring 46 and wire 48. The coils B- and B now hold the cores 35 and 36 down without any opposing force from the coils A and A In the apparatus shown in Fig. 4- the resultant action on the core 35 to hold it in its 'uppgr position is substantially constant and in ependent of variations within certain limits of the mainline voltage as any drop in the main line voltage will cause a corresponding drop in the secondary.

Having thus ful y described my invention and the preferable mode of applyin the principle thereof, what I claim and esire to secure by Letters Patent is:

1. The combination with an alternating current motor of the induction type, of primary mains therefor, means connected to two of said primary mains and 'to the secondary for controlling the speed of said motor independently of changes of voltage across the primary mains.

2. The combination with an alternating current motor of the induction type, of main lines of a source of multi-phase current supply, resistance in circuit with the secondary motor circuit, and means controlled by the voltage of said secondary circuit and comprising a circuit connected across only two of said main lines, for varying said resistance.

3. The combination with an alternating current motor ofthe induction type, of resistance in circuit with the secondary of said motor, opposing magnets-connected respectively to the primary and secondary of the motor, and means controlled. by said magnets for varying said resistance.

ifThe combination with an alternating current motor of the induction type, of resistance in the secondary circuit, and means including opposing magnets for decreasing said resistance controlled by the resultant of the primary and secondary voltage of the motor.

5. The combination with an alternating current induction motor, of an electromag-' netic controlling device comprising opposing magnets, said controlling device being operable by difi'erential current in said magnets determined by the voltages in the primary and secondaryof said motor from starting to fullspeed.

6. The combination of rent motor of the induction type and electro 'magnetic controlling devices therefor comprising a plurality of opposing elect-romagnets, half of the number of said opposing magnets being connected to the prlmary and the other half to the secondary of said motor. and switches successively operated by said magnets to eifectan acceleration of said motor. J u

7, The combination :with an alternating current induction motor, of resistance in the an alternating cursecondary motor circuit, and an electro-magnetic means comprising a plurality of oppositely actuating coils for varying said resistance in accordance with the voltage in said secondary.

8. The combination with an alternating current induction motor, of an electro-magnetic device in circuit with the secondary ing current motor, electro-responsive devices connected directly across two of the said main lines, a variable resistance in the secondary of the motor, electro receptive devices connected across two terminals of the resistance, electric circuits and connections for said electro-responsive devices, and means operated by said electro-receptive devices to gradually cut out said resistance as the motor increases in speed.

10. The combination with a two phase motor of the induction type, three main lines therefor, an electro-receptive device connected directly across any two of said main lines, of variable resistance in the secondary circuit of said motor, a second electro-receptive device arranged to be connected across any two of the terminals of said secondary circuit, and means operated by said electroreceptive devices to cut out said resistance as the motor increasesin speed.

11. The combination with a multiphase motor of the induction type, of supply mains therefor, electro-receptive devices connected in parallel directly across two of said mains, a variable resistance in the secondary ofsaid motor, additional electroreceptive devices connected across any two of the terminals of said secondary, and means operated by said electro-receptivedevices to gradually cut out said resistance until the motor attains full speed.

12. The combination with an alternating current eleotricmotor, of a variable resistance in the secondary circuit of the motor,

mechanism for cutting out said resistance, an electro magnetio devlce for operating. said mechanism, an addltlonal 'electro-ma device energized from the secondary CllClllli-i ofthe motor opposing said first-named elecetic 5 g tro-magnetic device so that as the motor increases in speed one of said electro-ma'gnetic,-

devices will graduall overcome the other and said resistance wi lbe gradually cut out.

. 13. The combination of a motor, of supply mains for supplying current to the motor,.'a plurality of electro-magnets connected. in parallel to said supply mains, a.'pl1 1rali'ty of;

additional electro-magnet-s acting in opposi-" l i O tion to the first-mentioned electro-magnets and connected to the secondary circuit of the motor, resistances in circuit with said secondary circuit, and means operated by said electromagnets for cutting out said resistances upon the motor attaining predetermined speeds.

l L. The combination of an alternating current electric -motor, resistances "in the secondary of. the motor, a plurality of electromagnetic devices controlling said resistances, one of said electro-magnetic devices being energized from mains of the motor and the other from the secondary circuit of the motor, and means operated by said electro-magnetic devices for cutting out said resistance, said devices being in opposition so that as the motor 1 attains predetermined speeds the resultant action of said electromagnetic devices eflects a gradual cutting out of circuit of said resistances.

15. The combination of an alternating current motor, a controlling device therefor, comprising an electro-magnet coil energized from the primary source of current, and a coil energized from the secondary of the motor, said coils opposing each other in their action.

16. In combination, an alternating current motor, a controllingdevice therefor comprising an electro-Inagnet coil directly connected toand energized from the primary source of current and a coil energized from the secondary of the motor, the secondnamed coil being constructed to have-a greater energizing strength than the firstnamed coil when the motor is first started but after the motor has attained a predetermined speed to have less strength, and a device controlled by said coils for effecting the acceleration of the motor.

17. The combination with a three-phase induction motor, supply mains therefor, an electro-magnetic device energized from any two of said mains, a variable resistance in circuit with the motor secondary, a second electro-magnetic device of difierent strength from said first-named electro-magnetic device and energized from said secondary, and electric circuits and connections for said devices, means controlling said resistance, and operated by said devices so that as the motor increases in speed said second named electro-magnetic device is radually var ed in strength to allow the st electro-magnetic device to efiect a successive cutting out of circuit of said resistance.

In testimony whereof, I have signed my name to this specification in the presence of two subscribing Witnesses.

DAVID LEONARD LINDQUIST.

WVitnesses CHARLES M. NISSEN, HENRY E. KIRBY.

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