US3809984A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Motor speed control system
Assignee: Allied Control Co Inc
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Filing: 1973-01-29
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Granted: 1974-05-07
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Expires: 1993-01-29
Abstract
Abstract The motor speed control system includes a bidirectional solid state switch which selectively connects and disconnects a series AC motor to an AC power source during each half cycle of the power supply signal. The decaying armature current is sensed when the motor is disconnected from the power supply at the end of each half cycle to determine the point in the next succeeding half cycle when the motor will be reconnected to the power supply.
Inventors
- 👤 H Hoge
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 18:13
CPC Classifications
B; B01; B01L; B01L3/00; B01L3/02; B01L3/0203; B01L3/0206; B01L3/021; B01L3/0217; H; H02; H02P; H02P25/00; H02P25/02; H02P25/10; H02P25/14; H02P25/145
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
179 words
A motor speed control system for a series connected AC motor powered by an AC signal from an AC power source and having a series connected armature and field winding comprising switching means connected in series with said motor across said power source, said switching means being operable to connect said motor directly to said power source, switch control means connected to said switching means and operating at a gating point in each half cycle of the AC signal to cause said switching means to connect said motor to the power source, said switching means operating to subsequently disconnect the motor from the power source toward the end of each half cycle of the AC signal, and sensing means connected to said armature and switch control means to sense the residual current from the armature when the motor is disconnected from said power source, said sensing means operating to cause said switch control means to determine the gating point in the next succeeding half cycle of the AC signal in response to the amplitude of said armature residual current.
Claim 2
Dependent Claim
179 words
A motor speed control system for a series connected AC motor powered by an AC signal from an AC power source and having a series connected armature and field winding comprising switching means connected in series with said motor across said power source, said switching means being operable to connect said motor directly to said power source, switch control means connected to said switching means and operating at a gating point in each half cycle of the AC signal to cause said switching means to connect said motor to the power source, said switching means operating to subsequently disconnect the motor from the power source toward the end of each half cycle of the AC signal, and sensing means connected to said armature and switch control means to sense the residual current from the armature when the motor is disconnected from said power source, said sensing means operating to cause said switch control means to determine the gating point in the next succeeding half cycle of the AC signal in response to the amplitude of said armature residual current.
Claim 3
Dependent Claim
68 words
The motor speed control of claim 1 wherein said switch control means is operative to set a minimum gating point in each half cycle of the AC signal for a no load operating condition of said motor, said gating point being advanced relative to said minimum gating point in accordance with the armature residual current sensed by said sensing means when a load is applied to said motor.
Claim 4
Dependent Claim
73 words
The motor speed control system of claim 2 wherein said switch control means includes reference voltage means for providing a reference voltage of substantially constant amplitude on each half cycle of AC power signal, a capacitor connected to charge from said reference voltage means, and threshhold means connected to conduct a signal from said capacitor when the charge on said capacitor reaches a threshhold level sufficient to cause conduction of said threshhold means.
Claim 5
Dependent Claim
63 words
The motor speed control system of claim 3 wherein said sensing means operates during the charging of said capacitor to provide an output signal to said capacitor having an amplitude which is a function of the amplitude of said armature residual current, said sensing means output signal combining with said reference voltage to increase the slope of the charging voltage for said capacitor.
Claim 6
Dependent Claim
38 words
The motor speed control system of claim 4 wherein said switch control means includes variable resistance means connected between said reference voltage means and said capacitor, said variable resistance means being operable to vary said minimum gating point.
Claim 7
Dependent Claim
59 words
The motor speed control system of claim 5 wherein said switching means includes a bidirectional solid state switch connected between said armature and power supply and having a gate electrode for triggering conduction of said switch upon the reception of a gating signal by said gate electrode, said gate electrode being connected to receive signals from said threshhold means.
Claim 8
Dependent Claim
86 words
The motor speed control system of claim 4 wherein said switching means is connected between said armature and said power supply, Said sensing means being connected between said armature and switching means and providing a current path for said armature residual current which extends from said armature to the opposite side of said motor, the sensing means including amplifier means connected to said current path for amplifying signals therein caused by said armature residual current, the output from said amplifier means being connected to said capacitor.
Claim 9
Dependent Claim
72 words
The motor speed control system of claim 7 wherein said amplifier means includes first and second complementary transistor means having commonly connected base and emitter electrodes connected to said current path and collector electrode circuits connected to a common output means, said complementary transistor means operating alternatively during the charging of said capacitor with each half cycle of said supply voltage to provide the output of said amplifier means to said capacitor.
Claim 10
Dependent Claim
79 words
The motor speed control system of claim 8 wherein said switching means is a bidirectional solid state switch having a gate electrode for initiating conduction by said switch upon reception thereby of a gating signal, said gate electrode being connected to receive signals from said threshhold means, said first and second complementary transistor means being respectively driven to saturation when conducting upon conduction of said bidirectional solid state switch to increase the amplifier means output to said threshhold means.
Claim 11
Dependent Claim
26 words
The motor speed control system of claim 9 wherein variable resistance means are provided in said current path to vary the gain of said amplifier means.
References Cited (Backward Citations)
US3586948A
Cited
US3564372A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-05-06 | 1977-11-05 | 1978-05-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-05-06 | 1981-11-05 | 1982-05-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-05-06 | 1985-11-05 | 1986-05-07 | $7700.00 | Window Closed / Lapsed |