Patent US3845372A successfully refreshed from Google Patents.
US3845372A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Circuit for starting electric motor from standstill with maximum torque
Assignee: Allis Chalmers Corp
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Filing: 1973-01-26
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Granted: 1974-10-29
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Expires: 1993-01-26
Abstract
Abstract The wheels of a vehicle are driven by synchronous motors energized from cycloconverters controlled by signals of selectively variable magnitude and phase and modulated at motor frequency. The signals for controlling the cycloconverters are generated in the output winding of a rotary vector adder having a pair of ninety-degree displaced energizing windings inductively linked to the output winding. Maximum motor torque is available at start and the displacement angle of the motor voltage is kept to zero and motor voltage is adjusted to a magnitude which will limit motor current to a value not exceeding 125 percent of full load by a current regulated starting circuit having a first operational amplifier which compares a current feedback signal proportional to motor current to a selectively variable power signal proportional to the desired output torque from the motor and set by a foot pedal, a current control amplifier which subtracts a speed signal proportional to motor r.p.m. from the power signal to derive a current control signal which sets maximum motor current, and a variable limit clamping emitter follower which receives the output from the first operational amplifier and provides an output voltage to only one energizing winding of the rotary vector adder and clamps the magnitude of said output voltage to an upper limit which varies with the current control signal so that the voltage applied to the vector adder energizing winding decreases as motor speed increases until the starting circuit output becomes zero at a predetermined motor speed.
Inventors
- 👤 A Geiersbach
- 👤 E Kaeser
- 👤 T Gilmore
- 👤 W Ringland
- 👤 M Neumann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 18:24
CPC Classifications
B; B60; B60K; B60K17/00; B60K17/04; B60K17/14; B60K17/145; B60K17/043; B60K17/046; B60K17/34; B60K17/356; B60L; B60L50/00; B60L50/10; B60L50/13; H; H02; H02P; H02P1/00; H02P1/16; H02P1/46; B60L2220/00; B60L2220/10; B60L2220/14; F; F02; F02B; F02B3/00; F02B3/06; Y; Y02; Y02T; Y02T10/00; Y02T10/60; Y02T10/64; Y02T10/70; Y02T10/7072
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
171 words
A circuit for starting an electric motor from standstill with maximum torque and limiting motor current during starting comprising, in combination, means for deriving a selectively variabale power signal whose magnitude is a function of the desired output torque for said motor, variable limit clamping means for clamping the magnitude of said power signal to an upper limit which varies in accordance with the magnitude of a signal applied to a control input thereof, tachometer means for deriving a speed signal which is a function of the speed of said motor, means for subtracting said speed signal from said power signal to derive a current control signal which varies inversely with the speed of said motor, said current control signal being applied ot said control input, means for deriving a current feedback signal which is a function of the current supplied to said motor, and means for comparing said current feedback signal to said power signal, the output from said comparing means being an input to said variable limit clamping means.
Claim 2
Dependent Claim
171 words
A circuit for starting an electric motor from standstill with maximum torque and limiting motor current during starting comprising, in combination, means for deriving a selectively variabale power signal whose magnitude is a function of the desired output torque for said motor, variable limit clamping means for clamping the magnitude of said power signal to an upper limit which varies in accordance with the magnitude of a signal applied to a control input thereof, tachometer means for deriving a speed signal which is a function of the speed of said motor, means for subtracting said speed signal from said power signal to derive a current control signal which varies inversely with the speed of said motor, said current control signal being applied ot said control input, means for deriving a current feedback signal which is a function of the current supplied to said motor, and means for comparing said current feedback signal to said power signal, the output from said comparing means being an input to said variable limit clamping means.
Claim 3
Dependent Claim
76 words
A circuit in accordance with claim 1 wherein said variable limit clamping means includes an emitter follower transistor having its base coupled to the output of said comparing means and its collector coupled to the output of said subtracting means, and a diode having its cathode and anode coupled respectively to said collector and said base, said means for supplying a terminal voltage to said motor being coupled to the emitter of said emitter follower transistor.
Claim 4
Dependent Claim
33 words
A circuit in accordance with claim 2 wherein said comparing means includes an operational amplifier which receives said power signal and said current feedback signal on its inverting and its noninverting inputs respectively.
Claim 5
Dependent Claim
45 words
A circuit in accordance with claim 2 wherein said subtracting means includes an operational amplifier which receives said power signal and said speed signal as inputs and whose output is said current control signal and is applied to said collector of said emitter follower transistor.
Claim 6
Dependent Claim
39 words
A circuit in accordance with claim 1 wherein said variable limit clamping means includes a diode having its anode and its cathode coupled respectively to the output of said subtracting means and to the output of said comparing means.
Claim 7
Dependent Claim
149 words
A circuit for starting an electric motor from standstill with maximum torque and for limiting motor current during starting comprising, in combination, means for deriving a selectively variable power signal whose magnitude is a function of the desired output torque from said motor, variable limit clamping means for clamping the magnitude of said power signal to an upper limit which varies in accordance with the magnitude of a signal appearing on a control input thereof, said variable limit clamping means including an emitter follower transistor whose base receives said power signal and whose collector is said control input and a diode connected across said collector and said base, means for applying a signal to said collector which varies inversely with the speed of said motor, and means for applying A terminal voltage to said motor whose magnitude is a function of the output from said variable limit clamping circuit.
Claim 8
Dependent Claim
149 words
A circuit for starting an electric motor from standstill with maximum torque and for limiting motor current during starting comprising, in combination, means for deriving a selectively variable power signal whose magnitude is a function of the desired output torque from said motor, variable limit clamping means for clamping the magnitude of said power signal to an upper limit which varies in accordance with the magnitude of a signal appearing on a control input thereof, said variable limit clamping means including an emitter follower transistor whose base receives said power signal and whose collector is said control input and a diode connected across said collector and said base, means for applying a signal to said collector which varies inversely with the speed of said motor, and means for applying A terminal voltage to said motor whose magnitude is a function of the output from said variable limit clamping circuit.
Claim 9
Dependent Claim
172 words
A circuit for starting an electric motor from standstill with maximum torque comprising, in combination, means for deriving a selectively variable power signal whose magnitude is a function of this desired output torque from said motor, tachometer means for deriving a speed signal which is a function of the speed of said motor, means for deriving a current feedback signal whose magnitude is a function of the current supplied to said motor, means for comparing said current feedback signal to said power signal, means for subtracting said speed signal from said power signal to derive a current reference signal, variable limit clamping means coupled to the output of said comparing means for limiting the output thereof to an upper limit which varies in accordance with the magnitude of a signal applied to a control input thereof, said current reference signal being applied to said control input, and means for supplying a voltage to the terminals of said motor whose magnitude is a function of the output from said variable limit clamping means.
Claim 10
Dependent Claim
172 words
A circuit for starting an electric motor from standstill with maximum torque comprising, in combination, means for deriving a selectively variable power signal whose magnitude is a function of this desired output torque from said motor, tachometer means for deriving a speed signal which is a function of the speed of said motor, means for deriving a current feedback signal whose magnitude is a function of the current supplied to said motor, means for comparing said current feedback signal to said power signal, means for subtracting said speed signal from said power signal to derive a current reference signal, variable limit clamping means coupled to the output of said comparing means for limiting the output thereof to an upper limit which varies in accordance with the magnitude of a signal applied to a control input thereof, said current reference signal being applied to said control input, and means for supplying a voltage to the terminals of said motor whose magnitude is a function of the output from said variable limit clamping means.
Claim 11
Dependent Claim
109 words
A circuit in accordance with claim 7 wherein said means for applying a terminal voltage to said motor includes a cycloconverter having output coupled to said motor, and means including a pair of displaced energizing windings inductively linked with an output winding for vectorially adding signals applied to said energizing windings to generate a signal in said output winding for controlling said cycloconverter which is selectively variable in phase and magnitude, and wherein the output of said variable limit clamping means is coupled to only one of said energizing windings, whereby the displacement angle of the output voltage from said cycloconverter supplied to said motor is zero at standstill.
Claim 12
Dependent Claim
176 words
A circuit for starting an electric motor with maximum torque from standstill comprising, in combination, means for deriving a selectively variable power signal which is a function of the desired output torque from said motor, means for deriving a current feedback signal which is a function of the magnitude of current supplied to said motor, first operational amplifier means for subtracting said current feedback signal from said power signal, variable limit clamping means for clamping the output from said first operational amplifier means to an upper limit which varies in accordance with the magnitude of a signal applied to a control input thereof, tachometer means for deriving a speed signal proportional to the r.p.m. of said motor, second operational amplifier means for subtracting said speed signal from said power signal to derive a current reference signal, said current reference signal being applied to said control input of said variable limit clamping means, and means for applying a terminal voltage to said motor whose magnitude is a function of the output from said variable limit clamping means.
Claim 13
Dependent Claim
176 words
A circuit for starting an electric motor with maximum torque from standstill comprising, in combination, means for deriving a selectively variable power signal which is a function of the desired output torque from said motor, means for deriving a current feedback signal which is a function of the magnitude of current supplied to said motor, first operational amplifier means for subtracting said current feedback signal from said power signal, variable limit clamping means for clamping the output from said first operational amplifier means to an upper limit which varies in accordance with the magnitude of a signal applied to a control input thereof, tachometer means for deriving a speed signal proportional to the r.p.m. of said motor, second operational amplifier means for subtracting said speed signal from said power signal to derive a current reference signal, said current reference signal being applied to said control input of said variable limit clamping means, and means for applying a terminal voltage to said motor whose magnitude is a function of the output from said variable limit clamping means.
Claim 14
Dependent Claim
212 words
A circuit for starting an alternating current electric motor from standstill with maximum torque and for limiting motor current during starting comprising, in combination, means for deriving a selectively variable power signal whose magnitude is a function of the desired output torque from said motor, variable limit clamping means for clamping the magnitude of said power signal to an upper limit which varies in accordance with the magnitude of a signal appearing on a control input thereof, means for applying a signal to said control input which varies inversely with the speed of said motor, means including a cycloconverter having its output coupled to the motor stator winding for applying a terminal voltage to said motor whose magnitude is a function of the output from said variable limit clamping means, and means including a pair of displaced energizing windings inductively linked with an output windiNg for vectorially adding signals applied to said energizing windings to derive a signal in said output winding for controlling said cycloconverter which is selectively variable in phase and magnitude, and wherein the output of said variable limit clamping means is coupled to only one of said energizing windings, whereby the phase angle of the output voltage from said cycloconverter supplied to said motor is zero at standstill.
Claim 15
Dependent Claim
212 words
A circuit for starting an alternating current electric motor from standstill with maximum torque and for limiting motor current during starting comprising, in combination, means for deriving a selectively variable power signal whose magnitude is a function of the desired output torque from said motor, variable limit clamping means for clamping the magnitude of said power signal to an upper limit which varies in accordance with the magnitude of a signal appearing on a control input thereof, means for applying a signal to said control input which varies inversely with the speed of said motor, means including a cycloconverter having its output coupled to the motor stator winding for applying a terminal voltage to said motor whose magnitude is a function of the output from said variable limit clamping means, and means including a pair of displaced energizing windings inductively linked with an output windiNg for vectorially adding signals applied to said energizing windings to derive a signal in said output winding for controlling said cycloconverter which is selectively variable in phase and magnitude, and wherein the output of said variable limit clamping means is coupled to only one of said energizing windings, whereby the phase angle of the output voltage from said cycloconverter supplied to said motor is zero at standstill.
Claim 16
Dependent Claim
226 words
A control for starting an electric motor from standstill with maximum torque and limiting motor current during starting and operating the motor over a speed range comprising, in combination, means (44, 430, 436) for deriving a selectively variable power signal whose magnitude is a function of the desired output torque from said motor, means (80) for deriving a speed signal which varies in accordance with the speed of said motor, means (178, 64) including a summing circuit (192) for deriving a control signal (VTs) which varies in accordance with said power signal and also as a function of said speed signal, means (58) for applying a terminal voltage (VT) to said motor which varies in accordance with said control signal (VTs), variable limit clamping means (470) in parallel to a portion of said control signal deriving means and receiving said power signal as an input and having its output coupled to said summing circuit (192) for clamping the magnitude of said power signal to an upper limit which varies in accordance with a current limit signal (VR) applied to a control input thereof, and means (CCA) for applying a current limit signal (VR) to said control input of said clamping means whose magnitude is a function of said power signal and which varies inversely with said speed signal and becomes zero at a predetermined motor speed.
Claim 17
Dependent Claim
226 words
A control for starting an electric motor from standstill with maximum torque and limiting motor current during starting and operating the motor over a speed range comprising, in combination, means (44, 430, 436) for deriving a selectively variable power signal whose magnitude is a function of the desired output torque from said motor, means (80) for deriving a speed signal which varies in accordance with the speed of said motor, means (178, 64) including a summing circuit (192) for deriving a control signal (VTs) which varies in accordance with said power signal and also as a function of said speed signal, means (58) for applying a terminal voltage (VT) to said motor which varies in accordance with said control signal (VTs), variable limit clamping means (470) in parallel to a portion of said control signal deriving means and receiving said power signal as an input and having its output coupled to said summing circuit (192) for clamping the magnitude of said power signal to an upper limit which varies in accordance with a current limit signal (VR) applied to a control input thereof, and means (CCA) for applying a current limit signal (VR) to said control input of said clamping means whose magnitude is a function of said power signal and which varies inversely with said speed signal and becomes zero at a predetermined motor speed.
Claim 18
Dependent Claim
66 words
A control in accordance with claim 11 wherein said motor (50) is an alternating current motor, said means for applying a terminal voltage to said motor includes a frequency changer (58) regulated by said control signal (VTs), and said means (178, 64) for deriving a control signal includes means (74) coupled to the rotor (52) of said motor for modulating said control signal at motor speed.
Claim 19
Dependent Claim
38 words
A control in accordance with claim 12 wherein said means for deriving a control signal (VTs) includes means (138, 178, SIN, COS) for selectively varying the phase of said control signal as a function of said speed signal.
Claim 20
Dependent Claim
51 words
A control in accordance with claim 11 wherein said means for applying a current limit signal (VR) to said control input of said clamping means includes means (CCA) for subtracting said speed signal from said power signal to derive said current limit signal (VR) which is coupled to said control input.
Claim 21
Dependent Claim
65 words
A control in accordance with claim 11 wherein said means for deriving a control signal (VTs) includes a function generator (178) for deriving a DC signal (vts'') which varies from zero at standstill in proportion to said power signal and also as a function of said speed signal, and wherein the output of said function generator (178) is an input to said summing circuit (192).
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-10-28 | 1978-04-29 | 1978-10-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-28 | 1982-04-29 | 1982-10-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-28 | 1986-04-29 | 1986-10-29 | $7700.00 | Window Closed / Lapsed |