US3811079A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dc motor control system
Assignee: Hitachi Ltd
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Filing: 1973-04-25
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Granted: 1974-05-14
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Expires: 1993-04-25
Abstract
Abstract A system for controlling the speed of a DC motor by means of a field control in which a rectifier in the form of a thyristor is connected to the armature of the motor for supplying a current in only one direction and is controlled to constitute a constant current control means. An integrator having a saturation characterisitc is provided for integrating the difference between a reference speed and an actually detected speed of the motor. The output of the integrator is added to the reference speed and the result of addition is compared with the actually detected speed so as to apply a field current instruction signal to a field current control means provided with a current negative feedback means.
Inventors
- 👤 S Shima
- 👤 Y Sakai
- 👤 K Tashiro
- 👤 Y Onoda
- 👤 T Narita
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 07:14
CPC Classifications
H; H02; H02P; H02P7/00; H02P7/06; H02P7/18; H02P7/24; H02P7/28; H02P7/298; H02P7/2985; B; B66; B66B; B66B1/00; B66B1/24; B66B1/28; B66B1/285; Y; Y10; Y10S; Y10S388/00; Y10S388/90; Y10S388/906; Y10S388/907; Y10S388/917; Y10S388/918
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
154 words
A DC motor control system comprising a DC motor, a first power converter means for supplying current in only one direction to the armature of said DC motor, means including said first power converter for controlling the armature current, a second power converter means for supplying current to the field winding of said DC motor, means for generating and applying applying a reference speed instruction signal, detecting means for generating a speed responsive signal, means for integrating the difference between the reference speed instruction signal and the actually detected speed responsive signal with a saturation characteristic, means for adding the output of said integrating means to the reference speed instruction signal, summing means for controlling said second power converter depending on the difference between the output of said adding means and the actually detected speed responsive signal, and means for detecting the field current to apply it as negative feedback to said summing means.
Claim 2
Dependent Claim
154 words
A DC motor control system comprising a DC motor, a first power converter means for supplying current in only one direction to the armature of said DC motor, means including said first power converter for controlling the armature current, a second power converter means for supplying current to the field winding of said DC motor, means for generating and applying applying a reference speed instruction signal, detecting means for generating a speed responsive signal, means for integrating the difference between the reference speed instruction signal and the actually detected speed responsive signal with a saturation characteristic, means for adding the output of said integrating means to the reference speed instruction signal, summing means for controlling said second power converter depending on the difference between the output of said adding means and the actually detected speed responsive signal, and means for detecting the field current to apply it as negative feedback to said summing means.
Claim 3
Dependent Claim
30 words
A DC motor control system as claimed in claim 1, further comprising means for increasing the armature current during the period of time in which the reference speed is varying.
Claim 4
Dependent Claim
85 words
A DC motor control system as claimed in claim 2, further comprising means for applying a signal representative of a constant current value, means for differentiating the reference speed instruction signal, means for detecting the absolute value of the differentiated reference speed instruction signal, means for combining the output of said absolute value detecting means with said signal representative of the constant current value, and means for applying the output of said combining means to said armature current control means as a current instruction 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) | 1977-05-13 | 1977-11-12 | 1978-05-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-05-13 | 1981-11-12 | 1982-05-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-05-13 | 1985-11-12 | 1986-05-14 | $7700.00 | Window Closed / Lapsed |