Patent US4013948A successfully refreshed from Google Patents.
Patent US3714534A successfully refreshed from Google Patents.
US3714534A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrical motor-damping circuit for a self-positioning system
Assignee: Eastman Kodak Co
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Filing: 1971-05-03
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Granted: 1973-01-30
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Expires: 1991-05-03
Abstract
Abstract A damping circuit for a DC motor. Driving the motor is a halfwave rectified current from an AC power source. A transistor and isolating diode are connected across the motor terminals. The base of the transistor is connected through a resistor to the output of the AC power source so that during the half cycles the motor is not driven the transistor is turned on to short-circuit the back voltage from the motor due to armature rotation. The drag produced on the armature is proportional to its rotational velocity and therefore equivalent to hydraulic damping but less expensive and simpler. One such transistor circuit is used for each of the two directions of motor travel in a servo system such as used in automatic focusing projectors.
Inventors
- 👤 H Hoadley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 20:19
CPC Classifications
H; H02; H02P; H02P7/00; H02P7/06; H02P7/18; H02P7/24; H02P7/28; H02P7/281; G; G03; G03B; G03B21/00; G03B21/14; G03B21/53
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
85 words
A damping circuit for a DC motor having terminals, windings and a rotatable armature and driven by a half-wave rectified current applied at the terminals from an AC power source, comprising: means for sensing half-cycles of the power source when said motor armature is rotating and undriven; means responsive to said sensing means for applying to the terminals current from said AC source and associated with the back voltage developed by said windings to damp said motor proportionally to the rotational velocity of said armature.
Claim 2
Dependent Claim
85 words
A damping circuit for a DC motor having terminals, windings and a rotatable armature and driven by a half-wave rectified current applied at the terminals from an AC power source, comprising: means for sensing half-cycles of the power source when said motor armature is rotating and undriven; means responsive to said sensing means for applying to the terminals current from said AC source and associated with the back voltage developed by said windings to damp said motor proportionally to the rotational velocity of said armature.
Claim 3
Dependent Claim
85 words
A damping circuit for a DC motor having terminals, windings and a rotatable armature and driven by a half-wave rectified current applied at the terminals from an AC power source, comprising: means for sensing half-cycles of the power source when said motor armature is rotating and undriven; means responsive to said sensing means for applying to the terminals current from said AC source and associated with the back voltage developed by said windings to damp said motor proportionally to the rotational velocity of said armature.
Claim 4
Dependent Claim
85 words
A damping circuit for a DC motor having terminals, windings and a rotatable armature and driven by a half-wave rectified current applied at the terminals from an AC power source, comprising: means for sensing half-cycles of the power source when said motor armature is rotating and undriven; means responsive to said sensing means for applying to the terminals current from said AC source and associated with the back voltage developed by said windings to damp said motor proportionally to the rotational velocity of said armature.
Claim 5
Dependent Claim
14 words
The invention of claim 1 wherein said applying means comprises at least one transistor.
Claim 6
Dependent Claim
23 words
The invention of claim 1 wherein said applying means comprises at least one transistor and said sensing means comprises current direction limiting means.
Claim 7
Dependent Claim
80 words
The invention of claim 1 wherein said applying means comprises two transistors and said sensing means comprises current direction limiting means associated on a one-to-one basis with said transistors, respectively, such that one said transistor and associated current direction limiting means is operative to damp said motor when said armature is rotating in one direction and said other transistor and associated current direction limiting means is operative to damp said motor when said armature is rotating in said other direction.
Claim 8
Dependent Claim
116 words
A damping circuit for a bidirectional DC motor having terminals, windings, and a rotatable armature and driven in either direction by a half-wave rectified AC current from an AC power source applied at the terminals, comprising: means for sensing the direction of rotation of said armature and half-cycles of the rectified current when said motor is rotating and undriven; means responsive to said sensing means comprising two channels, one associated with clockwise and the other associated with counterclockwise rotation of said armature for applying through said channels to the terminals current from said AC source associated with the back voltage developed by said windings to damp said motor proportionally to the rotational velocity of said armature.
Claim 9
Dependent Claim
116 words
A damping circuit for a bidirectional DC motor having terminals, windings, and a rotatable armature and driven in either direction by a half-wave rectified AC current from an AC power source applied at the terminals, comprising: means for sensing the direction of rotation of said armature and half-cycles of the rectified current when said motor is rotating and undriven; means responsive to said sensing means comprising two channels, one associated with clockwise and the other associated with counterclockwise rotation of said armature for applying through said channels to the terminals current from said AC source associated with the back voltage developed by said windings to damp said motor proportionally to the rotational velocity of said armature.
Claim 10
Dependent Claim
26 words
The invention of claim 5 wherein said channels comprise: at least two transistors operated at saturation; and impedance means for applying a selected amount of damping.
References Cited (Backward Citations)
US2965827A
Cited
US3184670A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-01-30 | 1976-07-31 | 1977-01-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-01-30 | 1980-07-31 | 1981-01-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-01-30 | 1984-07-31 | 1985-01-30 | $7700.00 | Window Closed / Lapsed |