US3688874A - Elevator motor control system employing power amplifier with output current limiting arrangement - Google Patents

Elevator motor control system employing power amplifier with output current limiting arrangement Download PDF

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Publication number
US3688874A
US3688874A US170072A US3688874DA US3688874A US 3688874 A US3688874 A US 3688874A US 170072 A US170072 A US 170072A US 3688874D A US3688874D A US 3688874DA US 3688874 A US3688874 A US 3688874A
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United States
Prior art keywords
car
power amplifier
control system
speed
polarity
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Expired - Lifetime
Application number
US170072A
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English (en)
Inventor
John Lusti
William Paul Reid
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Otis Elevator Co
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Otis Elevator Co
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Publication date
Application filed by Otis Elevator Co filed Critical Otis Elevator Co
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Publication of US3688874A publication Critical patent/US3688874A/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B66—HOISTING; LIFTING; HAULING
    • B66B—ELEVATORS; ESCALATORS OR MOVING WALKWAYS
    • B66B1/00—Control systems of elevators in general
    • B66B1/24—Control systems with regulation, i.e. with retroactive action, for influencing travelling speed, acceleration, or deceleration
    • B66B1/28—Control systems with regulation, i.e. with retroactive action, for influencing travelling speed, acceleration, or deceleration electrical
    • B66B1/30—Control systems with regulation, i.e. with retroactive action, for influencing travelling speed, acceleration, or deceleration electrical effective on driving gear, e.g. acting on power electronics, on inverter or rectifier controlled motor

Definitions

  • ABSTRACT An arrangement for an elevator control system employing a power amplifier for supplying excitation current to a dynamo winding for controlling the speed of the elevator car wherein the magnitude of the current of both polarities which the amplifier is capable of supplying is limited in response to the approach of the car to a predetermined distance of a landing at which it is stopping and wherein only the limitation for one polarity is removed in response to the generation of a signal to start in a direction corresponding to that one polarity.
  • the armature of a direct current hoist motor is connected in a closed circuit with the armature of a direct current generator which is driven by a suitable a.c. or d.c. motor.
  • the power amplifier supplies variable excitation current to the field of the dc. generator to control its output and thus horrt'ely the speed of the elevator car.
  • the excitation current capable of being supplied must be of both polarities to enable the car to operate in both the upward and the downward directions.
  • the magnitude of the excitation current capable of being supplied must be sufficient to enable the car to operate at a predetermined rated speed.
  • a control system for an elevator car which operates to transport loads between a plurality of landings in response to signals to start from and to stop at said landings.
  • a hoisting motor is provided for imparting motion to the car and a generator applies voltage to the motor to control its speed.
  • a field winding of the generator controls the magnitude of the voltage applied to the motor and a power amplifier supplies variable excitation current of either polarity to the field winding to enable the generator to apply sufficient voltage to said motor to operate the car at any speed from zero to a predetermined rated one in either the up or down direction of travel.
  • a resistance circuit is connected in series with the power amplifier and the field winding to limit the magnitude of both polarities of current that the power amplifier is capable of supplying to the field winding and thus the speed of the car in both directions of travel is limited to a speed less than the predetermined rated speed.
  • a conductance means provides a circuit in parallel with the resistance circuit to enable sufficient current of only the polarity associated with the particular direction to flow from the power amplifier to the field winding to enable the car to operate at the predetermined rated speed in the particular direction only.
  • the parallel circuit established by the conductance means is interrupted.
  • One of the features of the invention is that the magnitude of the resistance connected in series with the power amplifier and the field winding is varied in accordance with the magnitude of the load in the elevator car so that the speed to which the car is limited while the resistance is effective is substantially the same throughout the range from a fully loaded up traveling car to an empty down traveling car.
  • the sole FIGURE is a schematic wiring diagram of the circuitry of the presently preferred embodiment of the invention.
  • Main field 14 of the elevator hoisting motor is connected across a constant potential source schematically represented by battery 15.
  • motor armature 10 is connnected across the output of a direct current generator whose armature 16 is mounted on the same shaft as rotating element 18 of a suitable alternating or direct current drive motor, not otherwise shown.
  • Main field 20 of the direct current generator is connected in series with resistor RDG and resistance circuit 19 between the center tap of the secondary of transformer 23 and the up and down polarity output circuits from the silicon controlled rectifier of reversible single phase full wave rectifying circuit, or power amplifier, 22.
  • the input connections to power amplifier 22 are across the secondary of transformer 23 by way of lines S1 and S2.
  • the primary of transformer 23 is connected across a source of single phase, 60 cycle, alternating current indicated by lines 01 and 02.
  • This same source is also connected to the input circuit of control device 24 which may suitably take the form of a magnetic amplifier.
  • the output circuit of device 24 is connected to the gates of the silicon controlled rectifiers of circuit 22 to transmit firing pulses to these gates.
  • the output circuit of driving amplifier 26 is connected to another input circuit of device 24.
  • summation network 28 which may suitably include a static element operational amplifier.
  • summation network 30 which may suitably include a static element operational amplifier.
  • RGF resistor
  • summation network 30 is arranged with three input circuits. The first of these is connected to speed dictation apparatus described in detail in the foregoing Krauer et al.
  • the subject matter which constitutes the disclosed embodiment of the present invention includes resistance circuit 19 comprising up direction resistor elements GFl, GF3 and GFS together with down direction resistor elements GF2, GF4 and GF6 in conjunction with their associated electro-magnetic switch contacts UXl, DXl, HXI, HX2, LlRl, L2R1 and L2R2.
  • the coil circuits of the various electro-magnetic switches are not shown herein, but those skilled in the art will appreciate that that switch including contacts HXl and I-IX2 is operated to its actuated condition upon the generation of a signal to start to travel in either direction to enable the associated car CA to operate. Actuation of the switch engages its contacts I-IXl and I-IX2.
  • the switch is operated to its unactuated condition to open its associated contacts HXl and l-IX2 upon the car approaching within a predetermined distance of a landing at which it is stopping.
  • the switches including contacts UK] and DXl are each operated in conjunction with the switch with which contacts HXl and HXZ are associated when the car travels in their respective up and down directions.
  • the switch including contacts HR] and LIR2 is operated to its actuated condition to close contacts LlRl and open contacts LlR2 upon a predetermined load being indicated as having entered car CA.
  • This switch operates to its unactuated condition to reverse the condition of contacts LlRl and LlR2 upon less than this predetermined load being indicated as being in the car.
  • the switch including contacts L2Rl and L2R2 similarly operates to its actuated and unactuated conditions upon the indication of a second predeter mined load being in the car and not being in the car, respectively. This second predetermined load is greater than the first mentioned predetermined load.
  • a resistance circuit is provided in series with the power amplifier and the generator field winding which limits the current magnitude for both polarities of current that the power amplifier is capable of supplying to the field winding. This limits the speed attainable by the car in both directions of travel to one less than the rated installation speed.
  • a conductance means provides a circuit in parallel with the forementioned resistance circuit to enable sufficient current of only the polarity associated with the particular direction of travel in which the car is to start to flow from the power amplifier to the field winding.
  • the resistance circuit contains two load responsive switches. Each of these switches operates in response to the indication of a separate magnitude of load in the elevator car and each has associated contacts in parallel with resistor elements in both the up and down direction polarity circuits.
  • the magnitudesof the resistance of each of these circuits is variable in response to load in two steps.
  • a hoisting motor for said car operable to transport loads between a plurality of landings in response to signals to startfrom and to stop at said landings, a hoisting motor for said car, a generator applying voltage to said motor to control the speed thereof, a field winding for said generator controlling the magnitude of the voltage applied to said motor, a power amplifier operable to supply variable excitation current of either polarity to said filed winding to enable said generator to apply sufficient voltage to said motor to operate said car at any speed from zero to a predetermined rated speed in either the up or the down direction of travel, a resistance circuit connected in series with said power amplifier and said field winding limiting the magnitude of both polarities of current said power amplifier is capable of supplying to said field winding thereby limiting the speed of said car in both directions of travel to a speed less than said predetermined rated speed and conductance means responsive to a signal to start to travel in a particular direction providing a circuit in parallel with said resistance circuit to enable sufficient current of only the polarity associated with said particular direction to flow from said
  • said resistance circuit includes separate up and down direction resistor elements, each limiting the current of its associated polarity.
  • load responsive means operable to vary the magnitudes of the resistance of both the up and down direction resistor elements in response to the magnitude of the load in the elevator car.
  • said power amplifier includes an up polarity output circuit and a down polarity output circuit, said up and down direction resistance elements beingconnected to their respective output circuits.
  • said load responsive means includes a plurality of switches, each 0 erabl in res onse o ase rat nitude of load itvhereiiy the magnitudes f 531%- sistance of said up and down direction resistor elements are variable in a plurality of steps.

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  • Engineering & Computer Science (AREA)
  • Automation & Control Theory (AREA)
  • Control Of Direct Current Motors (AREA)
  • Types And Forms Of Lifts (AREA)
US170072A 1971-08-09 1971-08-09 Elevator motor control system employing power amplifier with output current limiting arrangement Expired - Lifetime US3688874A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US17007271A 1971-08-09 1971-08-09

Publications (1)

Publication Number Publication Date
US3688874A true US3688874A (en) 1972-09-05

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
US170072A Expired - Lifetime US3688874A (en) 1971-08-09 1971-08-09 Elevator motor control system employing power amplifier with output current limiting arrangement

Country Status (6)

Country Link
US (1) US3688874A (de)
JP (1) JPS5412835Y2 (de)
AU (1) AU462309B2 (de)
CA (1) CA960386A (de)
GB (1) GB1385093A (de)
ZA (1) ZA725374B (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4072212A (en) * 1975-08-28 1978-02-07 Mitsubishi Denki Kabushiki Kaisha Elevator speed control system
US4937507A (en) * 1988-06-17 1990-06-26 Mitsubishi Denki Kabushiki Kaisha Regenerative control system for motor generator
US5229558A (en) * 1989-10-31 1993-07-20 Kone Elevator Gmbh Control of an elevator hoisting motor during under voltage conditions in the main power source

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3410367A (en) * 1964-02-07 1968-11-12 Reliance Electric & Eng Co Elevator motor acceleration control by a stepped resistor responsive to distance from floor
US3536969A (en) * 1968-04-01 1970-10-27 Otis Elevator Co Elevator motor control

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3410367A (en) * 1964-02-07 1968-11-12 Reliance Electric & Eng Co Elevator motor acceleration control by a stepped resistor responsive to distance from floor
US3536969A (en) * 1968-04-01 1970-10-27 Otis Elevator Co Elevator motor control

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4072212A (en) * 1975-08-28 1978-02-07 Mitsubishi Denki Kabushiki Kaisha Elevator speed control system
US4937507A (en) * 1988-06-17 1990-06-26 Mitsubishi Denki Kabushiki Kaisha Regenerative control system for motor generator
US5229558A (en) * 1989-10-31 1993-07-20 Kone Elevator Gmbh Control of an elevator hoisting motor during under voltage conditions in the main power source

Also Published As

Publication number Publication date
GB1385093A (de) 1975-02-26
JPS4825458U (de) 1973-03-26
AU4539172A (en) 1974-02-14
JPS5412835Y2 (de) 1979-06-04
AU462309B2 (en) 1975-06-19
ZA725374B (en) 1973-05-30
CA960386A (en) 1974-12-31

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