US3678355A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Control for three phase a.c. motor
Assignee: FINCOR Inc
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Filing: 1970-08-11
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Granted: 1972-07-18
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Expires: 1990-08-11
Abstract
Abstract A control for a three phase A.C. motor elevator drive in which direction and desired speed signals, as dictated by customer and user demand, are electronically processed to provide intermediate ramp control signals. A summing circuit which utilizes the intermediate ramp control signal and a signal from an elevator motor speed and direction sensing circuit has an output which determines and controls the voltage input, via electronic trigger controls to thyristor controlled power and reversing switching circuits in at least two channels of the three phase A.C. input to a three phase A.C. drive motor. The motor control circuit incorporates a high rate of off-on and phase reversing switching with phase angle control of voltage and current to provide interrelated variable A.C. power supply for both drive and braking of the elevator drive motor in both directions of movement of the elevator cab.
Inventors
- 👤 Jiri B Bucek
- 👤 James R Shultz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 21:33
CPC Classifications
B; B66; B66B; B66B1/00; B66B1/24; B66B1/28; B66B1/30; H; H02; H02P; H02P23/00; H02P23/24
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
344 words
A motor control system for three phase A.C. motors, having three phase input leads, comprising: means for connecting three phase power lines to the three motor input leads including solid state thyratron type switching circuits in at least two of the connections from power phase lines to two of the motor input leads enabling forward and reverse power input to the motor, each of the forward and reverse circuits phase channels to the motor input leads including solid state thyratron type switching means, with trigger leads, enabling controlled current flow for each half cycle of the respective phase; a solid state trigger circuit for, and having triggering output circuits connected to, each switching means in each forward and reverse channel to said motor inputs responsive to timed cycle pulses of the associated power line phase and to control signals representing motor speed errors relative to a speed reference signal; tachometer means driven by said motor including a tachometer circuit providing outputs indicative of motor rotational direction and speed; and a control circuit for all of said trigger circuits having electrical inputs from a motor supervisory logic circuit providing input reference signals representative of desired speed which is inpUtted to a function generating means, the output of which is the desired running speed reference signal, said running speed reference signal being inputted with said tachometer output signal to a summing and amplifying means, the output of which is the amplified signal of the sum of said running speed reference signal and said tachometer output signal, said output of said summing and amplifying means providing control signals to said trigger circuits, the amplitude level of which from a neutral level is indicative of required phase conduction angle for forward and reverse power to maintain referenced motor speed, to provide trigger circuit half cycle timing and, for desired forward and reverse phase channels, to operate said trigger circuits to enable motor drive or electrical braking with requisite conduction angle of current in each half cycle of at least said two phases during each direction of motor rotation.
Claim 2
Dependent Claim
344 words
A motor control system for three phase A.C. motors, having three phase input leads, comprising: means for connecting three phase power lines to the three motor input leads including solid state thyratron type switching circuits in at least two of the connections from power phase lines to two of the motor input leads enabling forward and reverse power input to the motor, each of the forward and reverse circuits phase channels to the motor input leads including solid state thyratron type switching means, with trigger leads, enabling controlled current flow for each half cycle of the respective phase; a solid state trigger circuit for, and having triggering output circuits connected to, each switching means in each forward and reverse channel to said motor inputs responsive to timed cycle pulses of the associated power line phase and to control signals representing motor speed errors relative to a speed reference signal; tachometer means driven by said motor including a tachometer circuit providing outputs indicative of motor rotational direction and speed; and a control circuit for all of said trigger circuits having electrical inputs from a motor supervisory logic circuit providing input reference signals representative of desired speed which is inpUtted to a function generating means, the output of which is the desired running speed reference signal, said running speed reference signal being inputted with said tachometer output signal to a summing and amplifying means, the output of which is the amplified signal of the sum of said running speed reference signal and said tachometer output signal, said output of said summing and amplifying means providing control signals to said trigger circuits, the amplitude level of which from a neutral level is indicative of required phase conduction angle for forward and reverse power to maintain referenced motor speed, to provide trigger circuit half cycle timing and, for desired forward and reverse phase channels, to operate said trigger circuits to enable motor drive or electrical braking with requisite conduction angle of current in each half cycle of at least said two phases during each direction of motor rotation.
Claim 3
Dependent Claim
155 words
A motor output control system as claimed in claim 1, wherein each trigger circuit includes a bi-stable multivibrator with set and reset inputs and an output from each stage; timing means, including inductive coupling with the power line phase associated with the specific trigger circuit, providing sequential signals representing positive and negative half waves of the phase alternately on said multivibrator inputs to oscillate said multivibrator at a frequency corresponding to the associated phase frequency; said multivibrator outputs being coupled to provide a voltage transition signal at the start of each half cycle; means responsive to said multivibrator output to provide a saw tooth wave form with periods corresponding to half cycle periods; means comparing said conduction angle indicative control signals with said saw tooth wave form and providing corresponding square wave trigger output signals, with periods equal to desired half cycle conduction angles, to control the solid state switching device for the associated phase.
Claim 4
Dependent Claim
79 words
A motor control system as claimed in claim 2, wherein said voltage transition signals from said multivibrator outputs control a reset circuit for the saw tooth wave generator and said reset circuit includes a transistor having its collector connected to apply a preset voltage level to the reset terminal of the saw tooth generator and said voltage transition signals, via the multivibrator output, are applied to the base of said transistor to control application of said preset voltage level.
Claim 5
Dependent Claim
54 words
A motor control system as claimed in claim 3, wherein said saw tooth generator is an integrator, said transistor is PNP, said voltage transition signals are negative going and said connection from said transistor collector terminal is to the integrator inverting input enabling an integrator output with negative going integrating saw tooth wave forms.
Claim 6
Dependent Claim
92 words
A motor control system as defined in claim 2, wherein said triggering output circuits include two branch circuits, one for each half cycle; said conduction angle trigger output signals are applied to both of said branch circuits; each said branch includes inhibit gates having inhibit inputs connected to respective different ones of said multivibrator outputs to inhibit transmission of said triggering signal, alternatively, on said branch circuits so that transmission occurs through a branch circuit only when its related half cycle of the associated phase is occurring in the motor phase channel.
Claim 7
Dependent Claim
83 words
A motor control system as claimed in claim 1 wherein each of said solid state trigger devices is responsive to half cycle timing signals from the associated power phase and to said control signals indicative of required conduction angle to provide square wave trigger signals on said associated triggering output circuits for switching on and controlling current flow through the associated solid state thyratron type switching device during the desired conduction angle for each half cycle of the current in that associated phase.
Claim 8
Dependent Claim
45 words
A motor control system as claimed in claim 6, wherein each solid state trigger device provides conduction angle trigger signals on one or the other of two triggering output circuits while inhibiting output on the remaining one or the other of said triggering output circuits.
Claim 9
Dependent Claim
32 words
A motor control system as claimed in claim 6, wherein each of said triggering output circuits includes an isolation transformer between said trigger circuit and said solid state thyratron type switching device.
Claim 10
Dependent Claim
17 words
A motor control system as claimed in claim 8, wherein said isolation transformers are square wave transformers.
Claim 11
Dependent Claim
41 words
A motor control system as claimed in claim 1, wherein each said solid state thyratron type switching device includes at least two inverse parallel connected thyristors, each thyristor having its control circuit independent of the control circuit for the other thyristor.
Claim 12
Dependent Claim
60 words
A motor control system as defined in claim 1, wherein said motor is an elevator drive motor; and the supervisory logic is the elevator supervisory logic, said logic providing input signals which represent desired up and down movement of the elevator and other motor speed reference input signals of various voltage levels indicative of desired elevator speed in either direction.
Claim 13
Dependent Claim
40 words
A motor control system as defined in claim 1, wherein said control circuit output control signal is a variable voltage signal with positive and negative limits, the amplitude representing speed and the two polarities representing over or under speed conditions.
Claim 14
Dependent Claim
43 words
A motor control system as defined in claim 12, wherein selectively operable means provide circuit connections to all said trigger circuits from said control circuit output control signal to selectively provide connection angle control of all said solid state thyratron type switching devices.
Claim 15
Dependent Claim
76 words
A motor control system as defined in claim 13, wherein said circuit connections include two parallel safety interlock circuits, one for controlling said trigger circuits for ''''up'''' power channel switching devices to the motor and the other for controlling ''''down'''' power channel switching devices to the motor each said ''''up'''' and ''''down'''' power safety interlocks circuits having an inhibit circuit including means responsive to current flow in a respective ''''down'''' and ''''up'''' motor input phase channel.
Claim 16
Dependent Claim
111 words
A motor control system as defined in claim 14, wherein each interlock circuit controls an output control signal amplifier and its associated inhibit circuit includes: a current transformer, one associated with an ''''up'''' and the other associated with the ''''down'''' channel connection between a power phase line and associated reversing inputs to the motor; a rectifier circuit connected to the outputs of said current transformer; and a transistor switching device with its terminals connected to the rectifier output and between the signal input terminals to said amplifier whereby induced current in said current transformer will control said transistor switching device to render a control signal input to said associated amplifier ineffective.
Claim 17
Dependent Claim
91 words
A motor control system as defined in claim 15, wherein one of said interlock amplifiers is an inverter and directional diodes in the output control signal circuit to said interlock circuits direct positive signals to the amplifier input of one of said interlock circuits and negative signals to the amplifier input of the other of said interlock circuits; whereby the output signals of both interlock circuits have similar voltage level ranges, the total amplitudes of which represent desired half cycle conduction angles in the controlled phase input channels to the motor.
Claim 18
Dependent Claim
195 words
A motor control system as claimed in claim 1, wherein said control circuit includes a function error amplifier whose input receives a selected voltage level as a reference speed signal; a function generator amplifier with an inverting input connected to the output of the function error generator and a bypass feedback connection to its input and to the function errOr amplifier input to provide a ramp output integrated to a selected amplitude level; connections from the function generator output through up-down relay contacts to one or the other of normal or inverting inputs to a ramp signal inverter, the output of which is connected to a summing junction; a circuit from said tachometer output connection to apply to said summing junction, a signal indicative of actual motor speed directly related to the amplitude of said ramp inverter signal but opposite in polarity; the output of said summing junction being applied to an amplifier whose amplified output is said output control signal and whose amplitude is representative of the error in speed between the reference speed and actual motor speed and whose polarity represents over or under speed of the motor relative to said reference speed.
Claim 19
Dependent Claim
112 words
A motor control system as claimed in claim 1 wherein a solid state thyratron type switching circuit is incorporated in each of the three connections between the three phase power leads and the three phase motor input leads; two of said switching circuits having a pair of said solid state thyratron type switching means to enable switching of said two phase leads to reverse the power input direction to the motor; the third of said switching circuits having one of said solid state thyratron type switching means to control conduction angle current flow during each half cycle in the third phase input connection during both directions of power input to the motor.
Claim 20
Dependent Claim
47 words
A motor control system as claimed in claim 18, wherein a separate trigger circuit is provided for said third phase switching means and said separate trigger circuit receives said output control signals indicative of desired half cycle conduction angle during both ''''up'''' and ''''down'''' power input conditions.
Claim 21
Dependent Claim
20 words
A motor control system as claimed in claim 1, wherein said motor is a solid rotor three phase A.C. motor.
Claim 22
Dependent Claim
242 words
A motor control system for three phase A.C. motors, having three phase input leads, comprising: means for connecting three phase power lines to the three motor leads including switching circuits in at least two of the connections from power phase lines to two of the motor input leads enabling forward and reverse power to the motor, each of the forward and reverse circuit phase channels to the motor input leads including thyratron type switching means, with trigger leads, enabling controlled current flow for each half cycle of the respective phase; a trigger circuit for each switching means responsive to control signals representing motor speed errors relative to a speed reference signal; a control circuit for all of said trigger circuits to provide said control signals to said trigger circuits, the amplitude level of which from a neutral level is indicative of required phase conduction angle for forward and reverse power to maintain referenced motor speed, to provide trigger circuit half cycle timing and, for desired forward and reverse phase channels, to operate said trigger circuits to enable motor drive or electrical braking with requisitive conduction angle of current in each half cycle of at least said two phases during each direction of motor rotation; and selectively operable automatic safety interlock means providing a connection between said control circuit and said trigger circuits to prevent switching control in one three phase power direction during switching control in the other three phase power directions.
Claim 23
Dependent Claim
242 words
A motor control system for three phase A.C. motors, having three phase input leads, comprising: means for connecting three phase power lines to the three motor leads including switching circuits in at least two of the connections from power phase lines to two of the motor input leads enabling forward and reverse power to the motor, each of the forward and reverse circuit phase channels to the motor input leads including thyratron type switching means, with trigger leads, enabling controlled current flow for each half cycle of the respective phase; a trigger circuit for each switching means responsive to control signals representing motor speed errors relative to a speed reference signal; a control circuit for all of said trigger circuits to provide said control signals to said trigger circuits, the amplitude level of which from a neutral level is indicative of required phase conduction angle for forward and reverse power to maintain referenced motor speed, to provide trigger circuit half cycle timing and, for desired forward and reverse phase channels, to operate said trigger circuits to enable motor drive or electrical braking with requisitive conduction angle of current in each half cycle of at least said two phases during each direction of motor rotation; and selectively operable automatic safety interlock means providing a connection between said control circuit and said trigger circuits to prevent switching control in one three phase power direction during switching control in the other three phase power directions.
Claim 24
Dependent Claim
76 words
A motor control system as claimed in claim 21, wherein said circuit connections include two parallel safety interlock circuits, one for controlling said trigger circuits for ''''up'''' power channel switching devices to the motor and the other for controlling ''''down'''' power channel switching devices to the motor, each said ''''up'''' and ''''down'''' power safety interlock circuits having an inhibit circuit including means responsive to current flow in a respective ''''down'''' and ''''up'''' motor input phase Channel.
Claim 25
Dependent Claim
109 words
A motor control system as defined in claim 22, wherein each interlock circuit controls an output control signal amplifier and its associated inhibit circuit includes: a current transformer, one associated with an ''''up'''' and the other associated with the ''''down'''' channel between a power phase line and associated reversing inputs to the motor; a rectifier circuit connected to the outputs of said current transformer; and a transistor switching device with its terminals connected to the rectifier output and between the signal terminals to said amplifier whereby induced current in said current transformer will control said transistor switching device to render a control signal input to said associated amplifier ineffective.
Claim 26
Dependent Claim
89 words
A motor control system as defined in claim 22, wherein one of said interlock means is an inverter and directional diodes in the output signal circuit to said interlock circuits direct positive signals to the amplifier input of one of said interlock circuits and negative signals to the amplifier input of the other of said interlock circuits; whereby the output signals of both interlock circuits have similar voltage level ranges, the amplitudes of which represent desired half cycle conduction angles in the controlled phase input channels to the motor.
Claim 27
Dependent Claim
290 words
In combination in a motor control system for three phase A.C. motors, having three phase input leads, switching circuits in at least two power lines to two of the motor input leads enabling forward and reverse power input to the motor, each of the forward and reverse circuit phase channels to the motor input leads including thyratron type switching means enabling controlled current flow for each half cycle of the respective phase and trigger circuits for each switching means responsive to control signals representing motor speed errors relative to a speed reference signal; the improvement comprising a control circuit for all of said trigger circuits, said control circuit comprising: a function error amplifier whose input receives a selected voltage level as a reference speed signal; a function generator amplifier with an inverting input connected to the output of the function error generator and a bypass feedback connection to its input to the function error amplifier input to provide a ramp output integrated to a selected amplitude level; connections from the function generator output through up-down relay contacts to one or the other of normal or inverting inputs to a ramp signal inverter, the output of which is connected to a summing junction; a circuit from a motor tachometer output connection to apply to said summing junction, a signal indicative of actual motor speed directly related to the amplitude of said ramp inverter signal but opposite in polarity; the output of said summing junction being applied to an amplifier whose amplified output is said output control signal and whose amplitude is representative of the error in speed between the reference speed and actual motor speed and whose polarity represents over or under speed of the motor relative to said reference speed.
Claim 28
Dependent Claim
290 words
In combination in a motor control system for three phase A.C. motors, having three phase input leads, switching circuits in at least two power lines to two of the motor input leads enabling forward and reverse power input to the motor, each of the forward and reverse circuit phase channels to the motor input leads including thyratron type switching means enabling controlled current flow for each half cycle of the respective phase and trigger circuits for each switching means responsive to control signals representing motor speed errors relative to a speed reference signal; the improvement comprising a control circuit for all of said trigger circuits, said control circuit comprising: a function error amplifier whose input receives a selected voltage level as a reference speed signal; a function generator amplifier with an inverting input connected to the output of the function error generator and a bypass feedback connection to its input to the function error amplifier input to provide a ramp output integrated to a selected amplitude level; connections from the function generator output through up-down relay contacts to one or the other of normal or inverting inputs to a ramp signal inverter, the output of which is connected to a summing junction; a circuit from a motor tachometer output connection to apply to said summing junction, a signal indicative of actual motor speed directly related to the amplitude of said ramp inverter signal but opposite in polarity; the output of said summing junction being applied to an amplifier whose amplified output is said output control signal and whose amplitude is representative of the error in speed between the reference speed and actual motor speed and whose polarity represents over or under speed of the motor relative to said reference speed.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-07-18 | 1976-01-17 | 1976-07-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-18 | 1980-01-17 | 1980-07-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-18 | 1984-01-17 | 1984-07-18 | $7700.00 | Window Closed / Lapsed |