US1077355A

US1077355A - Alternating-current electromagnetic controller.

Info

Publication number: US1077355A
Application number: US61205711A
Authority: US
Inventors: David L Lindquist
Original assignee: Otis Elevator Co
Current assignee: Otis Elevator Co
Priority date: 1911-03-03
Filing date: 1911-03-03
Publication date: 1913-11-04
Anticipated expiration: 1930-11-04

Description

D. L. LINDQUIST.

ALTBRNATING CURRENT ELECTROMAGNETIC CONTROLLER.

APPLICATION TILED MAILS. 1911.

1,077,355, Patented Nov. 4, 1913.

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APPLICATION FILED MAR.3,1911.

Patented Nov. 4, 1913..

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UNITED STATES PATENT OFFICE.

DAVID L. LINDQUIST, OF YONKERS, NEW YORK, ASSIGNOR TO OTIS ELEVATOR COMPANY, OF JERSEY CITY, NEW JERSEY, A CORPORATION OF NEW JERSEY.

ALTERNATING-CURRENT ELECTROMAGNETIC CONTROLLER.

T 0 all whom it may concern:

Be it known that I, DAVID L. LIND UIST, a subject of the King of Sweden, residing at Yonkers, in the county of \Vestchester and State of New York, have invented a new and useful Improvement in Alternating-Current Electromagnetic Controllers, of which the following is a specification.

My invention relates to controlling apparatus especially designed for use in connection with alternating current electric motors.

The primary object of this invention is the provision of means for reducing the volume of current required in starting the motor.

With the usual arrangement of alternat ing current mechanism comprising a motor and brake as used, for example, in elevator practice, there is a heavy rush of current through the motor at the time it is connected to the mains. The brake magnet at the same time requires a heavy initial current owing to the fact that the magnet circuit of the brake is open until the brake is lifted. The present invention provides means for reducing the starting current applied to the motor until the brake has lifted so as to close its magnetic circuit and reduce the current flow through the brake magnet windings.

Other objects of the invention and the exact nature thereof will appear more fully hereafter.

In the accompanying drawings, Figure 1 is a diagrammatic View of an elevator comprising a motor and controlling apparatus designed in accordance with my invention; Fig. 2 is a front elevation view of the mechanism for operating the accelerating switches; Fig. 3 is a sectional end elevation view of the same.

Fig. 1 shows conventionally an elevator system comprising the car G, counterweight WV, hoisting cable 11, hoisting drum D, an electric motor M geared in the usual way to the hoisting drum, a brake magnet B, and a switch board 12. Journaled in the switch board 12 is a shaft 13 (Fi s. 2 and 3) geared by means of a gear whee 14 and intermediate gearing not shown to the sprocket wheel and chain gearing 15 (Fig. 1) which is driven by the hoisting drum. Loosely mounted on the shaft 13 IS a cam sleeve 16 adapted to be rotated in either direction from its initial position. The coil spring Specification of Letters Patent.

Application filed March 3, 1911.

Patented Nov. 4, 1913.

Serial No. 612,057.

17 serves to return the sleeve to such position after it has been rotated. An accelerating clutch magnet 18 is adapted, when energized, to connect the cam sleeve 16 for rotation with the shaft 13, in a manner presently to be described. A bail or hook 19 connected to the bottom of the magnet armature 20 surrounds one arm 21 of a bell crank lever 22. The latter is pivoted at 23 to a bracket 24 and has a weighted arm 25 and an arc-shaped segment 26 integral therewith. A lever 27 is pivoted at 28 to a lug formed on the sleeve 16 and carries an arc-shaped rack 29 which is provided with a number of gear teeth 30 at its inner surface adapted to engage but normally out of engagement with the gear teeth of a spur gear 31 fixed to the shaft 13. The spring 32 bears against the lever 27 and forces the rack 29 into contact with the segment 26. Directly over the spur gear 31 and a short distance therefrom is an areshaped stop-piece 33 which is carried by av bracket 34 secured to the switch board 12. This arc-shaped stop-piece has beveled ends 35 which are adapted to engage corresponding beveled ends of the rack 29 when the latter is rotated into engagement therewith.

The switch 4 shown in Fig. 3 is one of four similar accelerating switches 1, 2, 3 and 4, operated by means of the cam sleeve 16 and cams thereon. Each switch comprises a spring-pressed swinging contact arm 36 pivoted at 37 to a suitable bracket. The contact arm 36 carries a lug 38 which engages one end 39 of a cam lever 40 which is pivoted at 41. The other end of the cam lever carries a cam roller 42 which bears against the corresponding cam 4 which is one of a series of graduated cams 1, 2 3, and 4 The operation of the apparatus just described is as follows:WVhen the magnet 18 is energized its core 20 is lifted and the weighted arm 25 is enabled to swing the bell crank lever 22 about its pivot 23, since the magnet armature no longer bears downwardly on the arm 21 of the bell crank lever. The arc-shaped end 26 therefore moves upwardly carrying with it the rack 29 and causing the gear teeth on the latter to engage the teeth of the gear wheel 31. Since the latter is at this time rotating in one direction or the other a rotary motion is imright f agimplejaci 'thin'iig'ntl'coll ofythe eve s ng switch B, said Circuit being from the lead a tliro ng h parted to the cam sleeve 16 and the cams thereon operate to successively close the corresponding accelerating switches. For example'thecam 4 is rotated out of engagement with the cam roller 42 of the cam lever 40 and allowing the spring 45- to close the switch 4. When the rack 29 has rotated for substantially 90, it passes out of engagement with the concave surface of the arc-shaped piece 26 on the bell crank lever, and by force the rack out of engagement with the gear wheel 31, and into alinement with the arc shaped piece 26. The latter now acts as a stop to prevent the cam sleeve from being rotated backward by the centering spring 17. Should the spring 32 for any reason fail to disengage the rack from the gear 31, after the cam sleeve has rotated in either direction through substantially 90", any further rotation of the cam sleeve will cause the beveledjedge of the rack 29 to engage one ofgthe. corresponding beveled ends 35 of thes top piece 33, andthe rack 29 will be positively disengaged-from the gear andany further rotation absolutely prevent ed. Upon deenergizing the magnet. 18 the arInt-aure 2O will drop, carrying with it the lever arm 21 and causing the segment 26 to move out of alinement with the rack. 29. This enables the centering spring l'i' to rotate'the' cam 16 and connected cams back to normal position,. the cams thereby etf'ecfi ing the openingfoffthe "correspondihg switches.

Rete r g ne to. F1 trade are on t ed cg when, main linejswt the car switch lever};

i'ihel ds aLJ li v' mo ed, th wit f c edth o gh the reversing switch magnet, 'car switch K and back to the lead 12., The-reversing switch R is therefore closed and establishes a circuit for the potential switch ina et P. Said circuit may be traced from the lead I; through the magnet winding, and left hand contacts of the reversing switch R to. the wire 0., The potential switch closes and establishes the circuits for the stator of the motor. The lead 1) extends directly to the motor. The leads a and c are connected through the reversing switch R and potential switch P to the conductors a and 0, respectively, whichextend to the motor. The stator windings of the motOrthe'refore receive current and current is also induced in the rotor. The starting resistance X is at this time in circuit with the rotor. Said resistance includes in addition to. the usual amount of starting resistance an extra resistance a", so that the entire resistance X so doing enables the spring 32 to.

considerably below that required in starting the motor. \Vhen the potential switch is r closed as above described currentis also sup- 1 plied to the brake magnet B, and to the accelerating clutch magnet 18, the latter being connected between the leads 0' and 7).

The brake magnet operates as usual to lift the brake and the accelerating clutch mag- ,net lifts its core and closes a switch 18',

thereby short-circuiting the extra resistance a. The magnet 18, however, is much more sluggish than the brake magnet, that is it has more inertia in proportion to the magnetic pull and this sluggish tendency may be augmented if desired by some well known form of retarding device, such as the dashpot 44, which may be connected to some .iart of the apparatus, such as the core of the magnet, or the lever 21, as shown or to some other suitable part, so that the switch 18 is not closed until after the brake magnet has operated to lift the brake and close the m agnetic circuit of the brake, thereby reducing the current flow through the brake magnet. "It will thus be seen that the full starting current is not supplied to the 'mo- 'duced by retarding the full 'curr'entii'ow-to the motor'untilafter, the brake has operated. The cur nt thr g th m fvh n' h extra resistance as is in circuit is .sufiicie'nt' to preventthe motor from running backward when" thefbrake is lifted and maybe fbr'example aboutone-half of the current required to start momma When the estra resistance is shorft-circhited "by" the switch 18 the motor'receivs siifiici'ent current to start. The shaft 13 islthferefore" caused to rotate and'as the clutch'lever 27 hasbeen lifted by the accelerating clutch magnet, the cam sleeve is rotated'in the mannenheriiibefore set forth and effects the successive closing of the accelerating switches 1, 2,31 and 4:, thereby gradually short-circuiting the starting resistance X and permitting the motor to be brought up to full speed. When it is desired to stop the motor, the car switch K is brought back to central position, thereby effecting the opening of the reversing switch Rand potential switch P, thus cutting off the supply of current to the motor, the brake and the accelerating clutch magnet. The brake is therefore applied to bring the motor quickly to rest, The clutch members 31 and 29 are also disengaged permitting the parts to be restored to. initial position. If the car switch is moved to the left, the reversing switch R is operated and the leads a, and c are connected to the conductors c and a, respectively, thereby causing the motor to run in the reverse direction, otherwisethe operation is substantially ,as already described. 1

It will be understood that some of the features of electrical control ordinarily employed with this type of motor and elevator apparatus are omitted from the drawings for the sake of simplifying the illustration and because such additional features of control are, unnecessary to a full understanding of ,the present invention. 1

I do not claim any of the Specific features of mechanical construction illustrated in Figs. 2 and 3. This apparatus is specifically shown and described. for the purpose of clearly setting forth an operative andv practical construction embodying the principles of my invention;

I wish not to be limited to the exact arrangement and details disclosed, and I'wish; it further understoodtha't .the invention'may' be embodied in various specifically different forms of apparatus Within. the scope and spirit of my invention.

'WVhat I claim as new and desire to secure by Letters Patent of the United States .is

1. The combination with an electric motor, of an electromagnetic brake, resistance in a circuit of the motor, an electromagnet, means o er t d ther y fo cutti g, a p9 tion of said resistance out of the II1( )i o r circuit, means for simultaneously connect-. ing the motor, said electromagnet and brake magnet to a source of alternating current supply, and mechanism controlled by said electromagnet and operated by the motor to cut out the remainder of said resistance.

2. The combination of a motor, an electromagnetic brake, an electroresponsive device slower in operation than the brake magnet and controlled independently of the brake magnet and motor, starting resistance for the motor controlled by said clectroresponsive device, and switch mechanism for simultaneously establishing parallel circuits for the motor, the brake and said electroresponsive device. i 3. The combination with an electric motor comprising a stator and a rotor, of an electromagnetic brake having its magnet windings connected to the terminals of the stator, resistance in the'rotor circuit, an electroresponsive device controlling a portion of said resistance and operable independently of the brake and motor, said electroresponsire device being connected in parallel with said stator windings, and a device for connecting the circuits for the brake magnet, motor, and said electroresponsive device to a source of alternating current supply.

l. T he combination with an electric motor, of an electromagnetic brake, sectional resistance in a circuit of the motor, a switch controlling a portion of said resistance, an electroresponsive device for operating said switch, and mechanical means controlled by said electroresponsivedevice for effecting ;the short-circuiting of the remaining portion ofsaid resistance, 7 I

5. The combination with an electric motor, of starting resistance for the motor,

accelerating switches controlling said resistance, anextra resistance in the motor circuit and of sufiicient value, to prevent the .motor starting, a switch controlling said -ejxtra resistance, an electroresponsive device for operating said switch, and means dependent upon the operation of said electroresponsivedevice to effect the operation of said accelerating switches.

, 6. The combination of an electric motor ;comprising a stator and a, rotor, sectional starting resistance incircuitwith the rotor, accelerating switches controlling said resista-nce anj extrav resistance. preventing the motor from starting, a switch controlling said extra resistance, an electromagnet for operating said switch, and=mechanism controlled by; said electromagnet "for effecting .the successive? operation of said accelerating swi ches. .7 7, The combination. of analternating current t r ompr sing as t .a .a.

sectional starting resistance in circuit with tbjiifbtql ftl} extra resistance the rotor e reu t, a switch operative to short-circuit .said extra resistance, an electromagnet connected to operate said switch and having its electrical circuit connected in parallel with a winding of the stator, and mechanical means operated by the motor and controlled by said electromagnet for efiecting the gradual short-circuiting of the starting" resistance after said ma et is operated.

8. The combination of an electric motor, a sectional st-artingresistance for the motor, accelerating switches controlling said resistance, a mechanical device for successively operating said switches, a train of gearing comprising a clutch connecting the said mechanical device to the motor, an extra resistance, a switch controlling said extra resistance, and an electroresponsive device for operating said switch and said clutch.

9. The combination of an alternating current electric motor, an electromagnetic brake, an electroresponsive device, switch mechanism operative to establish the circuits for the motor, the brake magnetand said electroresponsive device, sectional starting resistance for the motor, a series of switches controlling said starting resistance, a mechanical device for operating said switches, means controlled by said electroresponsive device for connecting and disconnecting said mechanical device to and from the motor, an extra resistance, and a switch controlling said extra resistance and operated by said electroresponsive device.

10. The combination of an electric motor, an electroresponsive device, means for simultaneously connecting said parts to a sourceof current supply, and means for preventing the motor from taking a current sufficientto start the motor until said electroresponsive device has ope-rated.

11. The combination of an electric motor, means for connecting the motor to a source of current supply, and automatic means for temporarilypreventing the motor from taking sufficient'fiow of'current to start the motor.

12. The combination of an electric motor, a load device connected thereto, means for connecting the motor to a source of current supply, resistance in the motor circuit suflicient to prevent the motor from starting said load'device, and automatic means for reducing-theresistance 1n the motor circuit after the motor 1S"COI11'l6Cted to receive current. e

I 13: The combmatlonof an electric motor, QLPCIeCtIOI'GSPOIISIVG device, mea.ns for connecting saidi'elements:simultaneously to asource obcurrent supply, and means for reducing the maximum value of current supplied'to said elements below that required to simultaneously operate said elements.

14. The combination of an alternating current electric motor, an electro-responsive brake having its windings connected in parallel with the stator windings of the motor, means for connecting the motor and brake magnet to a source of alternating current supply, and means for preventing the maximum flow of current through the motor and brake windings exceeding that required to simultaneously operate the brake and start the motor.

15. The combination of an electric motor,

a brake, an electro-responsive device, means for supplying current to said parts simultaneously, said electro-responsive device being retarded so as to be slower in action than the brake, and resistance in a circuit of the motor controlled by said electro-responsive device.

In testimony whereof, I have signed my name to this specification in the pres'enceof two subscribing witnesses.

. DAVID, Lrunonrs'r;

WVitnessemi EDWARD A. FITCH,

GEORGE D. Rose.

Copiesiotfhlsiietentjnay be obtained or five cents each, by addressing the Commissioner '0! Patents. Y- 1 4... ,i- 7. .-wa g c n 1 .tit;