US1871353A - Elevator control system - Google Patents

Description

Aug. 9, 1932 H W.,W|LLIAMS 1,371,353

ELEVATOR CONTROL SYSTEM Original Filed March 27; 1928 INVENTOR Harold W.Williams ATTORN EY Patented Aug. 9, 1932 UNITED STATES PATENT OFFICE HAROLD W. WILLIAMS, OF WILKINSBURG,

HOUSE ELECTRIC & MANUFACTURING VANIA ELEVATOR CONTROL SYSTEM Original application filed. March 27, 1928, Serial No.

1929, Serial No. 371,838.

My invention relates to motor control sys tems and it has particular relation to control systems for elevators, hoists and slmilar machinery.

This application is a division of my application, Serial No. 265,003, filed March27, 1928, patented Sept. 29, 1931, N 0. 1,824,856.

One object of my invention is to provide a control system for elevators wherein the control of the direction and speed of the elevator will be actuated in a positive manner.

Another object of my invention is to provide a control system for alternatingcurrent elevators wherein direction and speed controlling devices will be positively actuated independently of fluctuations of current in the supply circuit.

It is also an objector my invention to provide a system for controlling a two-speed alternating current motor wherein a single set of accelerating resistors may be used for accelerating the motor on either the low or the high speed windings.

My invention may be described with reterence to the accompanying drawing, wherein the sole figure is a diagrammatic view representing my invention as applied to a two-- speed alternating current motor for operatlng an elevator.

The drawing illustrates an elevator car (a as suitably suspended upon a'cable Ce that passes over a hoisting drum D to a suitable counterweight CW. A hoisting motor M 1s illustrated as being directly coupled to the hoisting drum D, although it is to be understood that suitable gearing may be interposed between the motor and the drum. The motor M is of the squirrelcage type provided with two speed windings on the stator, the high. speed winding being designated by the character HS and the low speed winding by'the character LS. The two speed windings or the motor are arranged in the usual manner wherein the respective windings determine the number of poles in the stator of the motor to obtain the several speeds. The ratio of the number of poles to each other maybe of any desired value, preferably 3 to 1; that is, the high speed winding will contain, for example,

265,003. Divided and this application filedJune 18, Renewed March 16, 1931.

8 poles, while the low speed winding will be used to obtain 24 poles.

Suitable direction switches 1 and 2 are provided for controlling the direction in which the motor M will operates by selectively reversing the phases of power supplied to the high and, low speed windings, respectively. The direction switches 1 and 2 are suitably controlled through the actuation of a car switch CS mounted upon the elevator car 0.

The speed winding which will be in operation is determined through the actuation of a suitable switching device 10 illustrated as being of the cam actuated type operated by single pilot moter P for controlling the connection of the low or the high speed winding to a source of power. The pilot motor P'is connected for reversible operation When its windings are energizedby movement of the car switch CS in the counter-clockwise or clock-wise direction, respectively.

A suitable source of power is indicated by conductors I, II, and'III.

A single set of resistors 11 comprising a plurality of resistor sections 12 13, 14-15, and 16-17 are connected, respectively, in each of the three phase windings ofthe high and'the low speed stator HS and LS and terminate in a star-point 18. It will be observed that these resistor sections are common to both the high and the low speed windings and that the selection of the winding which will be operative at any time will be controlled, by the actuation of the'contact members db, or a'b, respectively, associated with the switching device 10, operated by the pilot motor P, dependent upon the direction in which the motor P is operated.

My system may be understood best with reference to an assumed operation of the elevator. j

Assuming that itis desired to move the elevator car C upwardly, the car. switch CS is moved in a clockwise direction, to complete a circuit for the up-direction switch 1 to cause the car to move upwardly. This circuit extends from the supply conductor I through conductors 20 and 21, contact mem-. bers22, 23 and 24 of the car switch CS, conone of the phase windings of the pilot'motor' P to the star-point 31 for this motor; from phase conductor II through conductors 2.8 and 32, the contact members. 33, 34 and 35- of the car switch CS, conductors 36 and 37, another of the phase windings of the pilot motor 'P of the star-point 31; and from phase conductor III through conductor 38 and the third phase winding of the motor P to thesta-r-point 31.

Rotation of the motor P operates the associated contact members. a and 6 into engagement by means of cam members 39' and 40, respectively. The operationof 'thecontact members a-and b of the switching device 10 will cause current to be supplied to the low speed winding LS by way of circuits which extend from supply. conductor 1' through conductors 20 and 42, the contact members 0 of up-direction switch 1, coniductors 43 and 44, the contact members a of the switching device 10, conductor 45, one of the phase windings of the low speed stator LS, conductor 46 and resistor sections 12 and 13 tothe star-point 18.; fro1nlinecon ductor II, through conductors 28 and 47, the contact members I) of rip-direction switch 1, conductors 48 and 49, the contact members. 6 of switching device 10, conductor 50, another of the phase windings of the low speed stator LS, conductor 51, resistor sections 14 and 15 to star-point 18; and from line conductor Ill through conductors 38 and 53,.a third phase winding of .low speed stator, conductor 54 and, resistor sections 16 and 17 to the star.- point 18.

The motor will thereupon start and accelerate on the low speed winding connection.

3 As the motor P continues to rotate, it engages and actuates its contact members 0 and cl, by means of cam members 54 and 55, respectively. It is assumed that. the dimensions and arrangement of the cams 54 and 55 and the; retardingefiectof dashpot T are such that a predetermined time elapses between the closing of the contact members a and Z2 and the contact members '0 and (Z. The motor P may be provided with a dash-pot T or other suitable retarding device for this purpose. Hence, at a predetermined time after current is supplied to the low speed winding LS, re-' termined time sistor sections 13, 15 and 17 will be shunted by the contact members 0 and cl thus supplying increased voltage to the winding LS. The motor M will thereupon accelerate the speed determined by the value of the voltage so supplied.

At a predetermined time thereafter, contact members 6 and 7 will be engaged and operated by cammembers 56 and 5?,respeetively (also arranged to engage and operate the respectivecontact members at a predeafter actuation of the contact members. 0 and d), and resistor sections 12, 14 and 16 will be excluded from the low speed winding circuits, thus supplying voltage to the low speed winding LS at increasing values until the wind ings are connected directly to the source of supply, and the motor will accelerate to substantially its synchronous speed for this winding.

Assuming that the car switch CS is moved to a greater extent in the same direction, then current will be supplied to the pilot motor P through circuits which extend from supply conductor 1 through conductors 20 and 21, contact members 22, 23 and 60 of the car switch CS, conductors 61 and 37 and one of the phase windings of the motor P to the star-point 31; from the supply conductor II through conductors 28 and 32, the contactmembers 33, 34 and 63 of car switch. CS, conductors 64 and 30, an other of the phase windings of the motor P to star-point 31; and from supply; conductor III through conductor 38 to thethirdnhase winding of the motor P to the star-point 31.

With this arrangement of the circuits, the pilot motor P will be reversed and will operate now in clockwise direction, openina all of the contact members a, 7), etc, previously closedand closing the contact members a and b to supply current to the high speed windings HS.

The initial voltage supplied to the high speed windings HS will be modified by reason of the inclusion of the resistors in the group 11 in circuit with this windingirmtil the pilot motor P moves to such a position that the cam members 54-55. and 56-57 will. again close the contact members 0-d and ef. It will be observed that the cam members 54,, 55, 56 and 57ers duplicated on opposite sides of the shaft S driven by the motor P; hence switches 0-d and ef will be operated regardless of the direction in whichthe pilot motor rotates.

Ifit'is now dcsi red to stop the elevator car, the car-switch Cs will be moved 1. ow speed position; that is. to such position as will break contact between the members 34 and 63, as well as 23 and 60, and re-cngago the contact members 34 and 35 as well as 23' and 29, thus reversing the windings of the pilot motor P and causing it to change its direction or rotation.

As the pilot motor P reverses its direction of operation, the resistor sect-ions 121%16 and 13-15 17 are progressively reconnected in circuit with the high speed windings HS to modify the torque exerted by the windings HS. As the pilot motor P continues in its reverse or counter-clockwise direction, the contact members a and Z) are opened while the contact members a and Z) of the switching device 10 are closed. As the motor P continues to rotate the contact members ccZ and e-f are progressively closed to shunt the resistor sections 131516 and 12-1t16. Inasmuch as the motor M is operating above the synchronous speed, for the low speed winding a dynamic breaking effect is produced to assist in slowing down the car.

When the motor speed has been reduced to substantially synchronous speed for the low speed winding LS, the car switch Cs may be moved to illustrated off position, thereby deenergizing the pilot motor P and the lip-direction switch 1, at which time it is assumed that a mechanical brake (not shown) will be applied to bring the motor in to rest.

The operation of the elevator car C in the down direction is similar in all respects to that described for its operation in the up direction. In this case, however, down-direction switch 2 will be energized to reverse the phases of current supplied to the high and the low speed windings, respectively.

It will be observed, therefore, that I have provided a control system for two-speed alternating current elevator equipment, wherein a single motor-operated switching device may be used to control accelerating resistances common to both of the circuits, the only additional apparatus necessary for the complete control of the motor being the direction switches 1 and 2 for determining the direction in which the motor M is to operate.

The illustrated and described embodiment of my invention is illustrative only and my system is susceptible to many changes and different modes of application. I, therefore, do not desire to be limited to any of the details shown and described except as defined in the appended claims.

I claim as my invention:

1. In a motor-control system, a multispeed alternating-current motor having windings for each speed, a source of power, means for controlling the direction of movement of said motor, means for selectively controlling the connection of said windings to said source, accelerating means comprising voltage-modifying meanscommon to the circuits for all of said windings and a single rotating-magnetic-field magnet for operating said selecting means and for excluding the voltage-modifying means from said circuits. I

2. In a motor-control system, a multispeed alternating-current motor having windings for each speed, a source of power, means for controlling the direction of movement of said motor, means for selectively controlling the connection of said windings to said source, accelerating means for said motor including voltage-modifying means common to the circuits for all of said windings, reversible rotating-magnetic-field magnet means movable in one direction for actuating said selecting means to connect one of said windings to said source and for ex eluding said voltage-modifying means from the circuit for that winding and movable in the opposite direction for actuating said selecting means to connect another of said windings to said source and to exclude the voltage-modifying means from the circuit for that winding.

3. In a motor-control system, a two-speed alternating-current motor, an alternatingcurrent source, means for controlling the direction of rotation of said motor, means for selectively establishing low-speed and high-speed connections of said motor to said source, a starting device for modifying an operating characteristic of said motor during acceleration to low speed and to high speed and a time controlled magnetic device for successively operating said selecting means and for controlling said starting device to ccelerate said motor under time con trol.

4. In a motor-control system, a two-speed alternating-current motor, an alternatingcurrent source, means for controlling the direction of rotation of said motor, a starting device for modifying an operating characteristic of said motor during acceleration to low speed and to high speed and a reversible magnetic device having an element operable from an ofl' position in one direction to establish low-speed connections of said motor to said source and to control said starting device, and operable from said ofl position in the other direction to establish high speed connections of said motor to said source and to control. said starting device and timing means for controlling the speed of movement of said element.

5. In a motor-control system, a two-speed alternating-current motor, an alternatingcurrent source, means for controlling the directionof rotation of said motor, a primary starting resistor for modifying an operating characteristic of said motor during acceleration to low speed and to high speed and a reversible magnetic device having an element operable from an ofi position in one direction to establish low speed connections of said motor to said source andto control said starting device, and operable from said ofii position in the other directionto establish high speed connections of said motor to said source and to control said starting device and timing means for controlling the speed of movement of said element.

In testimony whereof, I have hereunto subscribed my name this 15th day of June, 1929.

HAROLD W. VVILLIAMSQ

Images