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US3801888A
Expired / Lapsed
US
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Motor speed control circuit
Assignee: Hunt Electronics Co
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Filing: 1972-02-09
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Granted: 1974-04-02
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Expires: 1992-02-09
Abstract
Abstract Disclosed is a circuit responsive to an environmental parameter such as temperature, humidity, etc. for controlling the speed of a motor. The circuit includes circuitry for causing the motor to turn off at a first value of the environmental parameter and circuitry for causing the motor to turn on again at a second value of the parameter different from the first value by a predetermined amount.
Inventors
- 👤 H Faulkner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 23:50
CPC Classifications
G; G05; G05D; G05D23/00; G05D23/19; G05D23/20; G05D23/24; G05D23/1906
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
219 words
A motor speed control circuit including: means for generating a difference signal whose value represents the difference between the value of some environmental parameter and a predetermined value, means responsive to said difference signal for generating a motor speed control signal having a value determined by the value of said difference signal, said motor speed control signal generation means including means for generating a first signal proportional to said difference signal, means for generating a predetermined second signal having first and second amplitude levels, said first level being greater than said second level, and means for generating said motor speed control signal when the amplitude of said first signal is smaller than the amplitude of said second signal, and means for preventing the generation of said motor speed control signal when said difference signal varies in one direction to a first value and for enabling the generation of said motor speed control signal when said difference signal vaRies in the other direction beyond said first value to a second value, said preventing and enabling means including means responsive to the amplitude of said first signal exceeding said first amplitude of said second signal for generating a cut-off control signal and means responsive to said cut-off control signal for clamping the amplitude of said second signal at said second level.
Claim 2
Dependent Claim
219 words
A motor speed control circuit including: means for generating a difference signal whose value represents the difference between the value of some environmental parameter and a predetermined value, means responsive to said difference signal for generating a motor speed control signal having a value determined by the value of said difference signal, said motor speed control signal generation means including means for generating a first signal proportional to said difference signal, means for generating a predetermined second signal having first and second amplitude levels, said first level being greater than said second level, and means for generating said motor speed control signal when the amplitude of said first signal is smaller than the amplitude of said second signal, and means for preventing the generation of said motor speed control signal when said difference signal varies in one direction to a first value and for enabling the generation of said motor speed control signal when said difference signal vaRies in the other direction beyond said first value to a second value, said preventing and enabling means including means responsive to the amplitude of said first signal exceeding said first amplitude of said second signal for generating a cut-off control signal and means responsive to said cut-off control signal for clamping the amplitude of said second signal at said second level.
Claim 3
Dependent Claim
65 words
A circuit as in claim 1 wherein said preventing and enabling means further includes means responsive to the amplitude of said first signal falling below said second level amplitude of said second signal for generating an unclamping signal, and wherein said clamping means includes means responsive to said unclamping signal for causing the amplitude of said second signal to be increased to said first level.
Claim 4
Dependent Claim
205 words
A motor speed control circuit including means responsive to a difference in value between a first signal whose value represents an environmental parameter and a second signal whose value is predetermined for producing a difference signal whose value represents such difference, means for generating a firing signal, means for generating a motor speed control signal when the amplitude of said firing signal exceeds a certain level determined by the amplitude of said difference signal, the value of said motor speed control signal being a function of the value of said difference signal, means for generating a third signal having either first or second amplitude levels, the amplitude of said third signal being at said first level when said motor speed control signal is being generated, means operative to prevent the generation of said motor speed control signal when the amplitude of said firing signal exceeds a particular level determined by the amplitude of said third signal, and means responsive to the operation of said preventing means for causing said third signal generating means to change the amplitude of said third signal to said second level to thereby vary said particular level and thus the level of said firing signal at which said preventing means operates.
Claim 5
Dependent Claim
205 words
A motor speed control circuit including means responsive to a difference in value between a first signal whose value represents an environmental parameter and a second signal whose value is predetermined for producing a difference signal whose value represents such difference, means for generating a firing signal, means for generating a motor speed control signal when the amplitude of said firing signal exceeds a certain level determined by the amplitude of said difference signal, the value of said motor speed control signal being a function of the value of said difference signal, means for generating a third signal having either first or second amplitude levels, the amplitude of said third signal being at said first level when said motor speed control signal is being generated, means operative to prevent the generation of said motor speed control signal when the amplitude of said firing signal exceeds a particular level determined by the amplitude of said third signal, and means responsive to the operation of said preventing means for causing said third signal generating means to change the amplitude of said third signal to said second level to thereby vary said particular level and thus the level of said firing signal at which said preventing means operates.
Claim 6
Dependent Claim
187 words
A circuit as in claim 3 wherein said firing signal generating means includes a capacitor and a power source for charging said capacitor, said third signal generating means includes a potentiometer for generating a voltage signal at one terminal thereof, said voltage signal having either a first amplitude level or a second amplitude level, lower than said first amplitude level, the other terminal of said potentiometer being connected to a power source, said preventing means includes a triode switch having two power electrodes and a gate elctrode, one power electrode of which is connected to said capacitor and the gate electrode of which is connected to the tap of said potentiometer, said triode switch assuming a low impedance condition between the power electrodes thereof when the voltage across said capacitor exceeds the voltage at said gate electrode to thereby conduct current discharging said capacitor and preventing the generation of said motor speed control signal, and said causing means includes a locking circuit responsive to the conduction of current by said triode switch for clamping the voltage at said one terminal of said potentiometer to said second level.
Claim 7
Dependent Claim
39 words
A circuit as in claim 4 wherein said clamping circuit includes means responsive to the generation of said motor speed control signal for enabling the voltage at said one terminal of said potentiometer to increase to said first level.
Claim 8
Dependent Claim
112 words
A circuit as in claim 5 wherein said locking circuit includes a first transistor whose base electrode is connected to said other power electrode of said triode switch and whose collector electrode is connected to said one terminal of said potentiometer, a resistor interconnecting a power source with the collector electrode of said first transistor, and a second transistor whose base electrode is connected to the junction of said resistor and said first transistOr and whose collector electrode is connected to the base electrode of said first transistor, and wherein said enabling means includes a conductor interconnecting said motor speed control signal generating means and the base electrode of said second transistor.
Claim 9
Dependent Claim
147 words
A motor speed control circuit including: means for generating first and second signals, the value of said first signal being proportional to some environmental parameter and the value of said second signal being inversely proportional to the environmental parameter, means responsive to an applied signal for generating a motor speed control signal having a value determined by the value of the applied signal, means responsive to said applied signal for preventing the generation of said motor speed control signal when said applied signal varies in one direction to a first value and for enabling the generation of said motor speed control signal when said applied signal varies in the other direction beyond the said first value to a second value, and means for selectively applying said first signal and said second signal to said motor speed control signal generating means and to said preventing and enabling means.
Claim 10
Dependent Claim
147 words
A motor speed control circuit including: means for generating first and second signals, the value of said first signal being proportional to some environmental parameter and the value of said second signal being inversely proportional to the environmental parameter, means responsive to an applied signal for generating a motor speed control signal having a value determined by the value of the applied signal, means responsive to said applied signal for preventing the generation of said motor speed control signal when said applied signal varies in one direction to a first value and for enabling the generation of said motor speed control signal when said applied signal varies in the other direction beyond the said first value to a second value, and means for selectively applying said first signal and said second signal to said motor speed control signal generating means and to said preventing and enabling means.
Claim 11
Dependent Claim
71 words
A motor speed control circuit as in claim 7 wherein said first and second signal generating means includes sensing means for generating a third signal whose value is inversely proportional to the value of the environmental parameter, and differential amplifier means for generating said first and second signals, said first signal being inversely proportional to the value of said third signal and said second signal being proportional to said third signal.
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) | 1977-04-01 | 1977-10-01 | 1978-04-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-04-01 | 1981-10-01 | 1982-04-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-04-01 | 1985-10-01 | 1986-04-02 | $7700.00 | Window Closed / Lapsed |