US1002336A - Induction-motor-controlling apparatus. - Google Patents

Description

A. SUNDHB INDUCTION MOTOR CONTROLLING APPARATUS. APPLICATION FILED HOV.16, 1905.

1,002,336. Ementmi Sept. 5, 1911.

20 5/ WITNESSES:

' 'e, zgo z INVENTOR ATTORNEY "UNITED STATES PATENT OFFICE.

AUGUST SUNDIL'OF YONKERS, NEW YORK OF JERSEY CITY NEW JERSEY,

ASSIGNOB TO OTIS ELEVATOR COMPANY, A CORPORATION OF NEW JERSEY.

INDUOTION-MO'IOR-CONTROLLING APPARATUS.

Specification of Letters Patent.

Patented Sept. 5, 1911.

Application filed November 18. 1805. Serial No. 287,762.

Be it known that I, AUGUST SUNDH, a citizen of the United States, residing at Yonkers," in the county of Westchester and State of New York, have invented a new and useful Improvement in Induction-Motor-Controlling Apparatus, of which the following is a specification.

My invention relates to motor cont-rolling apparatus, and is herein shown applied to an elevator system, but it is not so limited, as it may have a general application.

()ne of the objects of1my invention is the provision of simple and efficient means for starting, operating, and'stopping an electric motor.

A further object of my invention is the provision of a mechanical. brake connected to the motor, and operated thereby in proportion to the speed thereof. A further object of the present invention,

- is the provision of means for operating a starting device for an electric motor in portion tothe speed thereof.

More particularly it is the object of the present .invention, to provide an electromechanical brake device for a motor, and combine such device with a motor starting device, both of such devices to be operated in proportion to the speed of the motor.

Other objects of the invention will appear hereinafter, the novel combinations of ele ments being pointed out 'in the claims at the end'of this specification.

In the single figure of the drawing, an elevator hoisting apparatus .H is shown, for operating the car C, inwhich is located the manual switch S for controlling the reversing switches R R, which in turn control the circuits to the elevator motor M. As will be seen, this motor is connected by a shaft 7 6 to the hoisting apparatus H. This hoisting apparatus may be of any desired type, but the drum type is shown since I deemit preferable. So far as my invention,

pro-

- hereinafter described, is concerned, the moa, b, 0, designate the mains which are connected'between some suitable source of alternating current supply, and a transformer T.

L designates a three pole main line switch.

When the lever 13 in the car C is moved into engagement with the rigidly fixed con tact strip 14, a single phase circuit is closed from the wire a to andthrongh the wire 12, lever 13, contact strip 14, wire 16, coil 2 of reversing switch R, wire 9, and thence to wire I). The coil or solenoid 2 will therefore be excited by the single phase current and lift its core 4 so as to movethe insulated contacts 8 and 7' carried thereby into engagement with the fixed contacts 5' and 6. This will have the effect of closing the circuits to the motor M, which may be traced as follows: From the conductor a,

moved into engagement with the contact strip 15, a single phase circuit is closed from Wire a through wire 12, lever 13,

contact 15, Wire 17, coil 2, wires 1 and 9, to wire.b. In this case the coil 2 will be excited with a single phase current and consequently its core 4 lifted so as to bring the insulated contacts 7 and 8 into engagement with the fixed contacts 5 and 6 respectively. This will result in the'reversal of the connections of the conductors a and c to the motor terminals 21 and 20, and therefore also a reversal of the rotation of the motor M.

It should be noted that I have herein shown laminated the frames 3 and 3 of the reversing switch electro-magnets, and I have also shownt-he cores. 4 and 4' laminated so that these" electro-magnets will be operated more efliciently by alternating currents. It is to be understood, however, that when a direct current motor is used for driving the elevator apparatus, I may use solid electro-magnet frames and cores if desired.

Connected across two of the conductors leading from the alternating current source of supply, I have shown a solenoid 24. In this instance this solenoid is connected between the phase wire 6 and the wire 18, by

' against t connected to the motor shaft 76.

means of the leads 22 and 23. The solenoid 24 when excited by single phase current, will move its core 26 to the right and thereby release the brake shoe B, which is connected to said core 26 preferably by a rod When the current through the coil 24 is cut off or interrupted,the spring 28 in the casin' 29 acts to apply the brake shoe B %e brake pulley P, which is rigidly adjusting screw 32 which is at the right of der 43 is moved to its upper adapted to said spring.

The magnetframe, which is herein shown laminated so as to adapt the brake magnet to alternating currents, is placed between the casing 29 and an additional casing 35. It will be noticed that each of these casings is cylindrical in form, and that the piston 30 is adapted to move in the casing 29, and an additional piston 34 is adapted to move in the cylinder 35. The piston 34 is connected by a rod 33 to the core 26, so as to move therewith. The piston 34 is in reality a valve provided with circumferential grooves 36 and 38, and with pistons 39 and 40. A hole 37 extends from the right-hand end of the piston 34 to the groove 36, into which it opens at 37. A pipe 77 establishes communication between the cylinder 35 and the cylinder or casing 29. When the elevator car is at rest and the brake applied, the pipe 77 establishes communication between the groove 36 andthe casing 29 to the right of the brake piston 30. A port 41 is shown in the casing 35, opposite the groove 38, and the pipe 42 extends be tween the casing 35 opposite said groove and the cylinder 43. v

The cylinder 43 is arranged vertically, but may be placed in any other desired position, as it does not depend upon gravity for its operation but may, however, by inverting the cylinder 43. A piston 44 in this cylinposition by a spring 48, and is moved downwardly against the action of said spring by means of the fluid pressure apparatus A, hereinafter described. The port 47 allows free movement to the piston 44; a'stem or red 45 connects the piston 44 to the bridge piece 46. which, when moved downwardly, is connect the fixed contacts 51 and 5 2, 57 and 58, etc., to cut out step-by-step, the starting resistance 78. This starting resistance may be delta connected as shown,

minals are connected by the leads 63, 64,-

and 66, respectively, to the slip rung-s 79, 80, and 81 of the rotor of the motor M. If the bridge piece 46 is moved downwardly so as to connect the contacts 51 and 52, it will be readily seen that the sections 55 and 56 will be short-circuited, since a wire 49 connects the terminal 50 to the bridge piece 46. The terminal 50 now in effect, includes the points 53 and 54, and bridge piece 46. Upon further downward movement of the bridge piece 46, the successive sections of the resistance 78 are cut out, and finally when the contacts 59 and 60 are electrically connected, all the sections, including that ,designated 67, are cut out and the motor may attain its maximum speed.

Some suitable fluid pressure apparatus A is connected to be driven by the motor M, and to produce the pressure in proportion to the speed of said motor. To illustrate the principle of my invention, 1 have herein shown an air pump adapted to be driven by eccentrics mounted on the motor shaft 76. The straps E, E, of said eccentrics are respectively connected by the eccentric rods 74 and 75 to the pistons 72 and 73, which areadapted to play alternately in the cylinders 70 and 71, and by means of suitable controlling, spring-pressed puppet valves, air is pumped from the atmosphere into the chamber 69 and thence forced through the pipe 68 into the cylinder 35 to the right of the piston 40. When the brake electro-magnet is deenergized, the fluid forced hrough the pi e 68 will con tinue through the passage 3 to the groove 36 and thence by way of pipe 77 into the casing 28 to the right of the piston 30. Preferably, the chamber in which the spring 28 is located is air tight, so as to increase the eiiiciency of the fluid pressure apparatus when moving the piston 30 to the left to increase the braking action on the brake pul icy 1?. When, however, the brake magnet is energized, its core 26 will be drawn to the right against the action of the spring 28 to release the brake shoe B. At the same time the piston 34 is moved to the right, so that the left hand portion of said piston will open communication between the cylinder 29 and the atmosphere through the pipe 77 and the aperture 78. The apparatus is so constructed that when the core 26 is thus moved to the right, the groove 36 will be placed over the pipe 42 so that communication-is established bet-ween the pipe 68 and the cylinder 43 above the piston 44 or below it if the s' ring 48 is omitted. The car switch having 8 operating positions, and the brake magnet then energized to release the brake shoe B, and one of the reversing switches R or R having been necessarily also operated, the

is preferably so designed, that the motor current will fiow through the motor stator to tend to rotate said motor to move the car in the desired direction. The resistance 78 M will now rotate at slow speed, whereupon the fluid pressure apparatus, which is herein shown as an air pump, willbe operated to roduce fluid pressure on the up per side 0? the piston 44. The bridge piece 46 will consequently begin to descend or be moved into engagement with the fixedcontacts connected to the starting resistance. A certain interval dependent upon the load to be driven must ela se, however, after the motor is started, beflhre, sufiicient pressure is brought to bear on the piston 44 to move the samejso that the bridge piece 46 will electrically connect the contacts -51 and 52. When this occurs, more current will flow through the stator circuits, and consequently the speed of'the motor will be increased. This will have the effect of increasing the speed of operation of the fluid pressure apparatus to move the piston 44 downwardly a greatendistance to effect the short circuiting of additional sections of the starting resistance. This action continues until the motor has been accelerated gradually to full speed in a predetermined time with any given load, and the bridge piece 46 connects the contact strips 59 and 60. As

the piston 44 is moved downwardly, the reaction of the spring 48 is gradually increased sothat greater fluid pressure is required to give the piston 44 a further movement. TlllS is taken care of, however, by the gradually increased rapidity of action of the fluid pressure apparatus A, due to the gradual acceleration of the motor M. The

eflect thereof will be a substantially uniform movement of the bridge piece 46 downwardly over the contact strips which it' successively connects. The bridge piece 46 is of suflicient thickness or width to engage a lower set of contacts before it leaves an upper set.

Var1ous changes may be made in the de-' .tails and arrangement of parts by those skilled in the art, without departing from the spirit and scope of my invention.

It will be noticed that after the piston 44 has been moved to its lowermost position, so as to effect the connection of the strips 59 and 60 by the bridge piece 46, the fluid pressure apparatus continues to exert a fluid pressure on the upper side of the piston 44 and thus holds the bridge piece 46 in its lowermost position. In order not to let this a pressure become too 7 may fit loosely in the cylinder 43 so that een moved to one of the tain distance below 'matically regulated great, the piston 44 the fiuid at very high pressure, may escape to the under side of said piston and through the aperture 47 to the atmosphere, or the apprture 47 may occupy such a position that w en too great a pressure is exerted on the piston 44, said piston will be moved a cersaid aperture to open the same, to a certain extent to allow the fluid to escape from above said piston through said aperture 47 to the atmosphere. This will have the effect of regulatin the maximum pressure on the upper si e of said piston. It should be further noted, however, that if the motor M is slowed down through any cause, as-by meansof a heavy load thrown on said motor after the same has been brought up to speed, the fluid pressure.,acting on the plston 44 will be reduced and the .pring48 will consequently act toefi'ect an upward movement of the bridge piece 46, and thus re-insert some of the sections of the starting resistance 78, and thus protect the motor and increase its tor ue so that it may be again brought up to all speed. The speed is, therefore, autofor varying loads.

Instead of having the resistance 78 connected to the rotor, the same may be connected to the stator circuits, so,that my invention may be used to control the current supplied to the stator. Such an arrangement however, is preferable only when direct current motors are used, for in such case the starting resistance could be placed in circuit with the armature and gradually cut out to effect a re-acceleration of the motor. My apparatus is also adapted to operate an adjustable transformer so as to vary the voltage which is applied to the motor, and thereby regulate the speed thereof.

When the car switch S is moved to open position, the current to the motor will be interrupted, and so also the current through the brake magnet. The brake spring 28 will thereupon act to apply the brake B to the brake pulley P. It has been found in practice, that by reason of the heavy rotors of induction motors, the brakeapglying means could not be easily made of cient strength to sto the motor in ashort space of time. I esire to adapt the ordinary brake-applying'means to thestopping of the motor, and have the fluid pressure apparatus cooperate therewith to stop the motor gradually in a minimum space of time. When the current is cut off from the motor, it still runs by momentum and operates the fiuid pressure apparatus A to, force the fluid through the pipe 68 to the cylinder 35. When the brake magnet is denergized, and the brake shoe B applied, the piston valve 34 will be moved to the left so that the fluid confined above the piston 44 can escape atmosphere. The aperture 7 8 tlirrg.

through the pipe 42 and thencearound the groove 38 through the aperture 41 to the atmosphere. The spring 48 will therefore act to move the piston 4A and bridge piece 46 to their original positions, and thus reinsert the resistance 78. If desired, the rate of upward movement may be regulated by varying the sizes of'the apertures 41 and 47, but it is preferable that the piston H should have a nearly free return movement, and retarded only to such an extent that it will be cushioned at the upper end of its movement. When the piston valve is left, the fluid pressure apparatus A, which is now being operated by the momentum driven motor M, will propel fluid under pressure through the pipe 68 into the cylinder 85, and thence through the passage 37 and port 37 through the groove 36, and thence by way of pipe 77 to the cylinder 28 at the right of the piston 30. Fluid pressure will therefore be exerted on the piston 30 to assist the brake spring 28 in applying the brake shoe B to the brake pulley P. It is evident that this extra braking action will be proportionate to the speed at which the motor M is rotated at the time the brake inagnet is deenergized. The action'of the spring 28 is practically constant and holds the motor shaft 7 6 stationary after the motor has been stopped. It should also be noticed that when the brake magnet is deenergized and the fluid pressure apparatus A is operated by the momentum driven motor M, the fluid within the cylinder 29 and the pipes connecting the same with the fluid actuator or propeller is gradually increased in pressure as there is no means for permitting the fluid to escape when the piston valve 34: is in the position shown. the efl'ect of further retarding or gradually stopping the rotor of the motor M, by reason of the gradually increasing action of the fluid pumped into the pipe 68. Further- 'more, when the motor is stopped, check valves between the air actuator A and the chamber 69 will confine the fluid under pressure within the pipe 68, and consequently also within the cylinder 29, thus assisting the spring 28 in holding the brake shoe B in firm engagement with the brake pulley I. Heavier loads may thercar C and held in position without set- W'hen the brake magnet is again onerglzed, and the piston 34 drawn to the right, communication will be established between the pipe 77 and the cylinder 35 to the left of the piston 34 so that the fluid under pressure within the cylinder 28 may escape through said pipe 77 into the cylinder 35, and thence through the aperture 7 8 to the may be omit ted however, as the brake magnet may be of suiiicient strength to act against both the spring 28 and the confined fluid under pressure,

'rangement of parts,

thus moved to the.

This has therefore be carried by to release the brake magnet B and hold the same released. In such case an elastic fluid such as air will be preferable.

Obviously those skilled in the art may make various changes in the details and arwithout departing from the principles of my invention. I therefore do not desire to be restricted or limited to the precise construction herein shown and described.

What I claim and desire to have protected by Letters Patent of the United States, is:

1. In an elevator, the combination with a motor, of motor controlling apparatus, means for operating said motor controlling apparatus, valve mechanism for controlling said operating means, brake mechanism controlling said valve mechanism, a device operated by the motor for operating said valve mechanism by fluid pressure, and means independent of the fluid pressure for restoring the valve mechanism to initial position.

2. In an elevator, the combination with a motor, of means for controlling the speed of the motor, a valve for controlling said speed-controlling-means, a device operated by fluid pressure for actuating said valve, elect-ro-responsive valve restoring means, and brake apparatus controlled by said electro-responsive means.

3. In an elevator, the combination with a motor, of fluid pressure apparatus substantially entirely automatic in operation and connected to the motor, starting appliances for the motor, means operated by fluid pressure supplied by said apparatus for operating the starting appliances, mechanism for controlling the application of fluid pressure to said starting-operatingmeans, brake apparatus controlling said mechanism', and means independent of the fluid pressure for restoring said controlling mechanism to initial position.

4. In an elevator, the combination with the piston connected to the part to be actuated, of a resilient device on one side of said piston, fluid pressure apparatus for effecting the movement of said piston, and permitting fluid to escape to regulate the maximum pressure on said piston.

5. In an elevator, the combination with a piston connected with the part to be operated, of a spring for moving said piston in one direction, means for propelling fluid directly to said piston to move the same in another direction, a valve in the path of said fluid and operable in one direction by fluid pressure for connecting the su ply of fluid to said piston, and means in ependent of fluid pressure for actuating said valve in the reverse direction into position to block the flow of fluid to said piston.

6. In an elevator, the combination with an electric motor, of accelerating mechanism when the car is therefor, means for propelling fluid to actuate said accelerating mechanism in proportion to the speed of said motor, electric means for controlling the flow of fluid, and reversing switch mechanism for controlling the said electric means.

7. In an elevator, the combination with a motor, of a source of power for said motor, a fluid actuator operated by said motor, motor accelerating means. means for directing a fluid from said fluid actuator to operate said accelerating means, electron'iecluinical means for controlling the flow of fluid, and reversing switch mechanism for controlling said elect-r0-mechanical means.

8. In an elevator, the combination with a motor, of two sources of power, one being electric and substantially constant in value, the other being fluid pressure and in strength proportionate to the speed of said motor; connections substantially all electrical to effect the operation of said motor by the electric power; means operated by fluid pressure for effecting the acceleration of the motor, and elcctro-mechanical means for controlling bot-h of'said powers.

S). In an elevator, the combination with an electric motor, of a fluid actuator driven only when said motor operates, starting switches for said motor, electric means for operating said starting switches, and meansoperated by the fluid actuator for controlling the acceleration of said motor.

10. In an elevator, the combination with a motor, of reversing switches therefor, starting resistance for. said motor, fluid pressure apparatus connected to be operated by said motor, means actuated by fluid pressure for varying said resistance to regulate the speed of said motor, and electro-mechanical means for controlling the application of fluid pressure to said resistance varying means. I

11. I11 an elevator, the combination with a car. of hoisting apparatus therefor, of a motor connected to drive said hoisting apparatus, fluid-ccnnpressing mechanism connected to the motor and driven thereby only in motion, means operated by the compressed fluid for controlling the acceleration ofsaid motor, a valve for controlling said means, and an electro-magnet for actuating said valve.

12. In an elevator, the combination with a car, of hoisting apparatus therefor, a. motor for driving said hoisting apparatus, two sources of power, one being electric and connected to the motor, and the other being fluid and proportionate in strength to the speed of the car, means operated by said powers to effect the acceleration and operation. of said motor and hoisting apparatus, and electric controlling means for said accelerating means.

13. In an elevator, the combination with a car and hoisting apparatus therefor, of a means for restoring said valve to normal position to effect a restoration of said accelerating means.

14-1 In an elevator, the combination with a car, of hoisting apparatus and motor, of two soru-ces of power, one being electrical and substantially constant in value and adapted to start the motor, means substantially all electrical for restoring the electric power, and the other power being fluid and proportionate in strength to the speed of the car, and means operated by said powers for controlling the acceleration of the motor.

15. In an elevator, the combination with a car and its hoisting apparatus, of a motor connected to said hoisting apparatus, fluidpropelling means connected to be driven only when the car is in motion, electric means for controlling the starting and stopping of the motor from' the car, and means operated by the fluid from said fluidpropelling means to control the acceleration of the car. 1

16. In an elevator, the combination with a car and its hoisting apparatus, of an alternating current motor connected to said hoisting apparatus, a fluid actuator connected to be driven by said motor. motor accelerating means, means for operating said accelerating means, and electrically controlled means for directing and controlling the fluid from said fluid actuator to effect theactuation of said motor accelerating operating. means.

17. In an elevator, the combination of a car and moving means therefor, comprislng a motor, motor controlling means, a fluid actuator, operated-by the motor and operable to supply fluid pressure proportional to the speed of the motor, and means con-. trolled electrically from the car for controlling the application of fluid pressure to said motor-controlling means to effect a gradual increase of speed of said motor.

18. In an elevator, the combination wlth a car and hoisting apparatus therefor, of a motorfor driving said hoisting apparatus, a fluid actuator connected to be driven by said motor, motor-controlling means, means for directing and controlling the fluid from said fluid actuator to said motor-controlling means, and electric means for effect-mg the operation of said fluid-controlling means from the car.

- the speed of the car,

19. In an elevator, the combination with a motor, of fluid-propelling means operated thereby, of a controlling valve therefor, an accelerating device for the motor, a piston connected to said device and arranged to be moved by the propelled fluid, means controlled fi-rom the car for operating said valve to open position, and means for automatically restoring the said valve to normal position.

20. In an elevator, the combination with a car and hoisting apparatus, of the driving motor, motor-controlling means, fluid-pressure apparatus for operating said means in proportion to the speed of the car, and automatic means connected to the ear for controlling said fluid-pressure apparatus.-

21. In an elevator, the combination with a motor, of a fluid actuator, operable to supply fluid at a pressure proportional to the speed of the motor, motor controlling means, means for establishing communication be tween the fluid actuator and said motor controlling means, a valve for controlling the application of fluid pressure to operate said motor controlling means, an electro-responsive device for moving said valve to supply position, and automatic means for moving said valve to exhaust position.

22. In an elevator, the combination of a car and moving means therefor, comprising an electric motor, accelerating means for said motor, a piston connected to said accelerating means, a resilient device on one side of said piston, fluid pressure apparatus for supplying fluid pressure proportional to the speed of the motor for eflecting the movement of said piston to operate said accelerating means, and electro-mechanical means for controlling said fluid pressure apparatus from the car.

23. In an elevator, the combination with a car and its motor, of accelerating means for said motor, a piston connected to said accelerating means, a spring for moving said piston in one direction, fluid pressure apparatus for moving the piston in the opposite direction to positions corresponding to the speed of the motor, a valve for controlling the supply of fluid 'to act against said piston, and means controlled -from the car for operating said-valve to open or close the same.

24 In an elevator, the combination with a car, of hoisting apparatus therefor, of a motor connected to drive said hoisting apparatus, motor-controlling means, a fluid actuator depending upon the operation of said motor to effect the operation of said motor-controlling means in proportion to and means controlled from the car for operating the said motor fluid actuator and motor controlling means.

the car for operating 25. In an elevator, the combination with a car, of hoisting apparatus therefor, of a drivingv motor, means for accelerating said motor in a predetermined time, a fluid actuator dependent upon the motor for operating said accelerating means, a valve and an elect-ro-responsive device controlled from said valve.

26. In an elevator, the combination with a car and its motor, of means for regulating the speed of said motor, comprising a fluid actuator connected tosaid motor,an opposition element, and means for cutting out portions of said opposition element; a valve for controlling said motor-speed regulating means, and means for operating said valve from the car.

27 In an elevator, car and its motor, of accelerating apparatus for said motor, fluid propelling and controlling means supplying fluid pressure corresponding to the speed of the motor for automatically operating said accelerating apparatus, means for controlling the application of fluid pressure to said accelerating apparatus, and means carried by the car for electrically controlling said fluid-pressurecontrolliiigmeans.

28. In an elevator, the combination with an electric motor, of a fluid actuator connected thereto, a brake, and electro-mechanical means for directing and controlling the flow of fluid to effect the application of said brake.

25). In an elevator, the combination with a motor, of a fluid actuator, a brake pulley on the motor shaft, a brake shoe associated with said pulley, a piston connected directly to said brake shoe, and means for directing and controlling the fluid from said fluid actuator to act on said piston to apply the brake.

30. In an elevator, the combination with a motor, of a fluid compressor, brake mechanism, means for applying said brake mechanism, and means for directing and controlling the fluid from said compressor to effect an additional. actuation of said brake.

31. In an elevator, the combination with an induction motor, of a brake, bralrercleasing means, brakeaipplying means, a fluid actuator, and means actuated by fluid from said fluid actuator to assist the brakcapplying means to apply said brake to retard or stop said motor.

In an elevator, the combination with an induction motor, of a fluid compressor,

b 'ake, means for applying said brake, and means for controlling and directing the fluid.

from said fluid actuator to effect an additional actuation of said brake.

33. In an elevator, the combination with an induction motor of a fluid actuator, a brake, brake-applying means, an elcc roresponsive device for releasing said brake,

motor, and an electro-responsive device, for

releasing said brake.

35. In an elevator, the combination with a car and hoisting apparatus therefor, an induction motor, a fluid compressor connected to be driven by said motor, starting and accelerating means connected to said motor, a brake, brake applying means, a valve,'an electro-responsive device for releasing said brake, and moving said valve to effect the operation of said starting and ac-' celerating means by fluid pressure, and means co-acting with said valve for d recting the fluid under pressure from said fluid compressor to assist said brake applying means in stopping the motor.

36. In an elevator, the combination witha motor, of a fluid compressor operated thereby, starting and accelerating means for said motor, means for controlling the application of fluid pressure to said startin and accelerating means, a brake, brdl e-applying means, and means co-acting with said controlling means for exerting an additional braking action by fluid pressure in proportion to the speed of said motor.

37. The combination with an alternating current motor, of alternating current electro-magnetic reversing switches therefor, accelerating means for said motor, and a fluid-actuator for operating said accelerating means. I

38. The combination with an electric motor, of reversing switches therefor, normally held in open position accelerating mechanism and means for operating the same, electric means for closing said switches, fluid pressure, and mechanism for automatically effecting the operation of said accelerating mechanism.

39. In an elevator, the combination with a driving motor, of accelerating apparatus therefor, a piston connected to said accelerating apparatus, a spring acting upon one side of the piston to move the same in one direction, fluid-pressure apparatus acting upon the other side only for moving the piston inthe opposite direction, a valve for controlling the supply of fluid to act against said piston, and means controlled from the elevator for operating said valve.

40. In an electric elevator, the combination with an alternating current motor, of alternating current electro-magnetic starting switches therefor, accelerating means for said motor, and a fluid-actuating device connected to the motor for operating said accelerating means.

41. The combination with a motor, of an acceleratin device for the motor, means operated by uid pressure for controlling said device, a brake pulley, an electromagnet having a movable core, a brake shoe connected to the magnet core, a valve connected to 'said core and controlling said fluid pressure, and means for controlling the electromagnet. a

42. The combination with an electric motor,'of a starting resistance for the motor, a device operated by fluid pressure for controlling said resistance, means for supplying fluid pressure to said device, an electromagnet and controlling means therefor, said magnet comprising a movable core, a brake pulley for the motor, a brake shoe connected to the magnet core, and a valve connected to said core and controlling the supply of fluid pressure to the resistance-controlling-device.

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

AUGUST SUN DH.

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