US3593078A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Starting and operating control for an ac motor powered by a dc power supply
Assignee: Boeing North American Inc
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Filing: 1969-09-08
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Granted: 1971-07-13
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Expires: 1989-09-08
Abstract
Abstract An AC Motor Control, wherein the AC motor is powered by a DC power supply through a DC to AC converter circuit, and wherein the control has an AC current sensor for producing a current signal indicative of the current supplied to the motor which signal is coupled to the converter to prevent excessive current drain on the power supply under starting condition and an AC voltage sensor for producing a voltage signal indicative of the potential across the motor leads and this voltage signal is used to control the converter under operating conditions so that synchronous speed is maintained. Since, under operating condition, the current is inherently substantially stable at rated current, a switch is incorporated responsive to the current signal at rated current to decouple the current signal from the converter and couple the voltage signal thereto.
Inventors
- 👤 Ernest H Domshy
- 👤 Victor Moller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 14:30
CPC Classifications
H; H02; H02H; H02H7/00; H02H7/08; H02H7/0833; H02P; H02P1/00; H02P1/16; H02P1/46
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
245 words
In combination with a motor whose starting inrush current is substantially larger than said motor''s normal operating current, the combination comprising: controllable power means for providing controllable current and voltage to said motor; limiting means for continually limiting the output current from said power means to a value that is substantially equal to the value of said motor''s normal operating current; said limiting means comprising: current sensor means for sensing the instantaneous current drawn by said motor, and producing a current sensor control signal corresponding to said instantaneous motor current; and means for applying said current sensor control signal to said controllable power means for limiting the output current from said power means to a value substantially equal to the value of said motor''s normal operating current; voltage control means for controlling the output voltage from said power means to a value suitable to maintain motor synchronism, said voltage control means comprising voltage sensor means for sensing the instantaneous voltage at said motor, and producing a voltage sensor control signal corresponding to said instantaneous voltage; means for applying said voltage sensor control signal to said controllable power means; means for applying said current sensor control signal to said controllable power means for limiting the output current from said power meAns to a value substantially equal to the value of said motor''s normal operating current. said current sensor control signal being operative during motor acceleration, and said voltage sensor control signal being operative during motor-stabilized operation.
Claim 2
Dependent Claim
245 words
In combination with a motor whose starting inrush current is substantially larger than said motor''s normal operating current, the combination comprising: controllable power means for providing controllable current and voltage to said motor; limiting means for continually limiting the output current from said power means to a value that is substantially equal to the value of said motor''s normal operating current; said limiting means comprising: current sensor means for sensing the instantaneous current drawn by said motor, and producing a current sensor control signal corresponding to said instantaneous motor current; and means for applying said current sensor control signal to said controllable power means for limiting the output current from said power means to a value substantially equal to the value of said motor''s normal operating current; voltage control means for controlling the output voltage from said power means to a value suitable to maintain motor synchronism, said voltage control means comprising voltage sensor means for sensing the instantaneous voltage at said motor, and producing a voltage sensor control signal corresponding to said instantaneous voltage; means for applying said voltage sensor control signal to said controllable power means; means for applying said current sensor control signal to said controllable power means for limiting the output current from said power meAns to a value substantially equal to the value of said motor''s normal operating current. said current sensor control signal being operative during motor acceleration, and said voltage sensor control signal being operative during motor-stabilized operation.
Claim 3
Dependent Claim
219 words
In combination with a motor whose starting inrush-current is substantially larger than said motor''s normal operation current, the combination comprising: I. controllable power converter means for providing controllable current and voltage to said motor; II. means for limiting the output current from said converter to a value that is substantially equal to the value of said motor''s normal operating current, said limiting means comprising A. current sensor means for sensing the instantaneous current drawn by said motor, and producing a current sensor control signal corresponding to said instantaneous motor current; B. means for applying said current sensor control signal to said controllable power converter for continually limiting the output current from said power converter to a value substantially equal to the value of said motor''s normal operating current; III. means for controlling the output voltage from said power converter to a value suitable to maintain motor synchronism, said voltage control means comprising C. voltage sensor means for sensing the instantaneous voltage at said motor, and producing a voltage sensor control signal corresponding to said instantaneous voltage; D. means for applying said voltage sensor control signal to said controllable power converter; IV. means for causing said current sensor control signal to be operative during motor acceleration, and for causing said voltage sensor control signal to be operative during motor-stabilized operation.
Claim 4
Dependent Claim
219 words
In combination with a motor whose starting inrush-current is substantially larger than said motor''s normal operation current, the combination comprising: I. controllable power converter means for providing controllable current and voltage to said motor; II. means for limiting the output current from said converter to a value that is substantially equal to the value of said motor''s normal operating current, said limiting means comprising A. current sensor means for sensing the instantaneous current drawn by said motor, and producing a current sensor control signal corresponding to said instantaneous motor current; B. means for applying said current sensor control signal to said controllable power converter for continually limiting the output current from said power converter to a value substantially equal to the value of said motor''s normal operating current; III. means for controlling the output voltage from said power converter to a value suitable to maintain motor synchronism, said voltage control means comprising C. voltage sensor means for sensing the instantaneous voltage at said motor, and producing a voltage sensor control signal corresponding to said instantaneous voltage; D. means for applying said voltage sensor control signal to said controllable power converter; IV. means for causing said current sensor control signal to be operative during motor acceleration, and for causing said voltage sensor control signal to be operative during motor-stabilized operation.
Claim 5
Dependent Claim
50 words
The combination of claim 2 wherein said last means comprises a voltage signal switch connected between said voltage sensor means and said converter; and means for applying at least one of said current sensor control signals to said voltage signal switch for controlling the state of said voltage signal switch.
Claim 6
Dependent Claim
53 words
The combination of claim 2, wherein said last means comprises a current signal switch connected between at least one of said current sensors and said converter; and means for applying at least one of said current sensor control signals to said current signal switch, for controlling the state of said current signal switch.
Claim 7
Dependent Claim
81 words
The combination of claim 2 wherein said last means comprises a voltage signal switch connected between said converter; means for applying at least one of said current sensor control signals to said voltage signal switch for controlling said voltage signal switch; a current signal switch connected between at least one of said current sensors and said converter; and means for applying at least one of said current sensor control signals to said current signal switch for controlling said current signal switch.
Claim 8
Dependent Claim
76 words
The combination of claim 2 wherein said last means comprises universal switch means, connected to the input of said converter, for determining which control signals are applied to said converter; means for applying said current sensor control signals to said universal switch; means for applying said voltage sensor control signals to said universal switch; and means for applying at least one of said current sensor control signals to said universal switch for controlling the state thereof.
Claim 9
Dependent Claim
247 words
In combination with a multiphase AC motor whose starting inrush current is substantially larger than said motor''s normal operation current, the combination comprising: I. controllable multiphase power converter means for providing multiphase controllable current and voltage to said motor; II. means for continually limiting the output current from each phase of said converter to a value that is substantially equal to the value of said motor''s normal opErating current, said limiting means comprising A. current sensor means, positioned in at least one of said phases, for sensing the instantaneous current drawn by said phase of said motor, and producing a current sensor control signal corresponding to said instantaneous motor current; B. means for applying said current sensor control signal to said controllable power converter for continually limiting the output current from said phase of said power converter to a value substantially equal to the value of said motor''s normal operating current; III. means for controlling the output voltage from said power converter to a value suitable to maintain motor synchronism, said voltage control means comprising C. voltage sensor means for sensing the instantaneous voltage of at least one phase at said motor, and producing a voltage sensor control signal corresponding to said instantaneous voltage; D. means for applying said voltage sensor control signal to said controllable power converter; IV. means for causing said current sensor control signal to be operative during motor acceleration, and for causing said voltage sensor control signal to be operative during motor-stabilized operation.
Claim 10
Dependent Claim
247 words
In combination with a multiphase AC motor whose starting inrush current is substantially larger than said motor''s normal operation current, the combination comprising: I. controllable multiphase power converter means for providing multiphase controllable current and voltage to said motor; II. means for continually limiting the output current from each phase of said converter to a value that is substantially equal to the value of said motor''s normal opErating current, said limiting means comprising A. current sensor means, positioned in at least one of said phases, for sensing the instantaneous current drawn by said phase of said motor, and producing a current sensor control signal corresponding to said instantaneous motor current; B. means for applying said current sensor control signal to said controllable power converter for continually limiting the output current from said phase of said power converter to a value substantially equal to the value of said motor''s normal operating current; III. means for controlling the output voltage from said power converter to a value suitable to maintain motor synchronism, said voltage control means comprising C. voltage sensor means for sensing the instantaneous voltage of at least one phase at said motor, and producing a voltage sensor control signal corresponding to said instantaneous voltage; D. means for applying said voltage sensor control signal to said controllable power converter; IV. means for causing said current sensor control signal to be operative during motor acceleration, and for causing said voltage sensor control signal to be operative during motor-stabilized operation.
References Cited (Backward Citations)
US2146778A
Cited
US3189810A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-07-12 | 1975-01-11 | 1975-07-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-07-12 | 1979-01-11 | 1979-07-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-07-12 | 1983-01-11 | 1983-07-13 | $7700.00 | Window Closed / Lapsed |