US4129816A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Stepping motor control circuit
Assignee: AT&T Teletype Corp
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Filing: 1977-08-10
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Granted: 1978-12-12
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Expires: 1997-08-10
Abstract
Abstract A stepping motor is described having two operative modes, the first mode being a normal rotary mode and the second a stationary mode. During rotary operation, the induced energy created by interruption of the current flow through the energized phase winding is dissipated quickly by a zener diode connected across the winding. In the stationary mode, a pulsed current is fed to one of the phase windings of the motor to assure stationary positioning of the rotor. During stationary operation, the zener diode is shunted with a second conventional diode providing a low impedance path to the current induced in the phase winding upon de-energization. This low impedance path greatly reduces the energy dissipated during the off condition of the pulsed current thereby greatly reducing motor power requirements during stationary operation.
Inventors
- 👤 Edmund C. Feldy
- 👤 Dennis L. Stephens
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 15:55
CPC Classifications
H; H02; H02P; H02P8/00; H02P8/14; H02P8/16
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
104 words
In combination with a stepping motor having a plurality of stator phase windings each being successively energized during rotary operation with at least a first one of the phase windings being energized over a predetermined time period with a pulsed current during stationary operation and means for dissipating the induced energy in at least said first winding upon de-energization, the improvement comprising: means for selectively reducing the energy dissipated by said dissipating means during stationary operation to a lower value than during rotary operation so as to increase the average current through said first pulsed winding and thus the operational efficiency of the combination.
Claim 2
Dependent Claim
104 words
In combination with a stepping motor having a plurality of stator phase windings each being successively energized during rotary operation with at least a first one of the phase windings being energized over a predetermined time period with a pulsed current during stationary operation and means for dissipating the induced energy in at least said first winding upon de-energization, the improvement comprising: means for selectively reducing the energy dissipated by said dissipating means during stationary operation to a lower value than during rotary operation so as to increase the average current through said first pulsed winding and thus the operational efficiency of the combination.
Claim 3
Dependent Claim
45 words
The apparatus of claim 1 wherein said dissipating means exhibits a predetermined voltage drop through which the current produced by the de-energization of said first phase-winding during rotary operation passes and wherein said reducing means serves to reduce said predetermined voltage drop during stationary operation.
Claim 4
Dependent Claim
49 words
The apparatus of claim 2 wherein said dissipating means comprises a first diode connected across said first coil and a second diode selectively connected in parallel with said first diode by said reducing means during stationary operation, said second diode having a lower threshold voltage than said first diode.
Claim 5
Dependent Claim
37 words
The apparatus of claim 3 wherein said reducing means comprises a switch responsive to the operative mode of the motor and serve to connect said second diode across said first diode during stationary operation of the motor.
Claim 6
Dependent Claim
37 words
The apparatus of claim 4 wherein said switch comprises a transistor with said second diode being connected in series with the collector-emitter junction of the transistor and the series diode-transistor combination being connected across said first diode.
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) | 1981-12-11 | 1982-06-12 | 1982-12-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-12-11 | 1986-06-12 | 1986-12-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-12-11 | 1990-06-12 | 1990-12-12 | $7700.00 | Window Closed / Lapsed |