US3575652A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Motor control circuit with semiconductor switching means and transformer and capacitor biasing means
Assignee: Doosan Bobcat North America Inc
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Filing: 1969-06-30
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Granted: 1971-04-20
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Expires: 1989-06-30
Abstract
Abstract An electric motor is connected to a direct current electrical power source through a silicon controlled rectifier that is cyclically turned on by a triggering circuit and turned off by a commutating circuit. A semiconductor diode is connected in parallel with the silicon controlled rectifier in a reverse biased direction relative to the direct current source. The motor power circuit operates so that the diode is forward biased during part of the switching cycle by the action of a capacitor and transformer, and then, upon being reverse biased, momentarily carries part of the motor current in its reverse current direction thereby sharing the load current with the silicon controlled rectifier.
Inventors
- 👤 James H Snyder
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 09:21
CPC Classifications
H; H02; H02P; H02P7/00; H02P7/06; H02P7/18; H02P7/24; H02P7/28; H02P7/285; H02P7/29; Y; Y10; Y10S; Y10S388/00; Y10S388/907; Y10S388/917; Y10S388/918
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
200 words
An electrical motor control system comprising: a direct current power source having a positive and a negative terminal, a saturable core transformer having two windings with a common terminal and so wound as to have induced voltages of opposite polarities at their ends opposite the terminal when there is a change in the electrical current flowing between these ends, a condenser connected between the end of one of said windings and the negative terminal of said power source, a direct current motor connected between the end of the other of said windings and the positive terminal of said power source, a switching device connected between the common terminal on said transformer and the negative terminal of said power source, a control means for cyclically turning said switching device on in response to the voltage at the common terminal of the transformer when said voltage is positive with respect to the negative terminal of said power source, means for turning said switching device off in response to the voltage at the common terminal of said transformer being negative with respect to the negative terminal of said power source, whereby said direct current motor is energized by unidirectional pulses of electrical current.
Claim 2
Dependent Claim
200 words
An electrical motor control system comprising: a direct current power source having a positive and a negative terminal, a saturable core transformer having two windings with a common terminal and so wound as to have induced voltages of opposite polarities at their ends opposite the terminal when there is a change in the electrical current flowing between these ends, a condenser connected between the end of one of said windings and the negative terminal of said power source, a direct current motor connected between the end of the other of said windings and the positive terminal of said power source, a switching device connected between the common terminal on said transformer and the negative terminal of said power source, a control means for cyclically turning said switching device on in response to the voltage at the common terminal of the transformer when said voltage is positive with respect to the negative terminal of said power source, means for turning said switching device off in response to the voltage at the common terminal of said transformer being negative with respect to the negative terminal of said power source, whereby said direct current motor is energized by unidirectional pulses of electrical current.
Claim 3
Dependent Claim
21 words
An electrical motor control system as claimed in claim 1 in which said saturable core transformer has a square hysteresis loop.
Claim 4
Dependent Claim
43 words
An electrical motor control system as claimed in claim 1 in which: said direct current motor is a series wound motor with its field winding in the circuit between the armature of said motor and the end of one of said transformer windings.
Claim 5
Dependent Claim
31 words
An electrical motor control system as claimed in claim 1 including: a semiconductor diode connected parallel with said switching device and in a reverse biased direction relative to said electrical source.
Claim 6
Dependent Claim
43 words
An electrical motor control system as claimed in claim 1 including: a semiconductor diode having a relative slow reverse recovery characteristic connected in series with said motor and said direct current power source and in reverse biased direction relative to said power source.
Claim 7
Dependent Claim
72 words
An electrical motor control system as claimed in claim 1 wherein: said switching device is a silicon controlled rectifier, having a control terminal, connected in series with the source and the motor in the forward biased direction relative to the source, and said control means comprises a trigger circuit adapted to selectively apply a pulse at a selected variable repetition rate to the control terminal to turn the silicon controlled rectifier on.
Claim 8
Dependent Claim
44 words
An electrical motor control system as claimed in claim 1 wherein: said switching device has a control terminal and said control means comprises a means for applying a signal at a selected cyclic rate to the control terminal to turn the switching device on.
Claim 9
Dependent Claim
70 words
An electrical motor control system as claimed in claim 2 in which: said switching device is a silicon controlled rectifier connected in series with the source and the motor in a forward biased direction relative to the source, and wherein said control means comprises an adjustable trigger circuit adapted to cyclically turn on the silicon controlled rectifier, and a commutating circuit adapted to cyclically turn off the silicon controlled rectifier.
Claim 10
Dependent Claim
72 words
An electrical motor control system as claimed in claim 2 in which: said switching device is a silicon controlled rectifier, having a control terminal, connected in series with the source and the motor in a forward biased direction relative to said source, and said control means comprising a trigger circuit adapted to selectively apply a pulse at selected variable repetition rate to the control terminal to turn the silicon controlled rectifier on.
Claim 11
Dependent Claim
70 words
An electrical motor control system as claimed in claim 2 in which: said switching device is a silicon controlled rectifier connected in series with tHe source and the motor in a forward biased direction relative to the source, and wherein said control means comprises an adjustable trigger circuit adapted to cyclically turn on the silicon controlled rectifier, and a commutating circuit adapted to cyclically turn off the silicon controlled rectifier.
Claim 12
Dependent Claim
52 words
An electrical motor control system as claimed in claim 4 wherein said motor has a series connected field winding and an armature winding, and said semiconductor diode has its cathode connected between the field winding and armature winding and is thereby connected in series with said motor armature winding and the source.
Claim 13
Dependent Claim
306 words
An electrical motor control system as claimed in claim 5 in which: said motor has a series connected field winding and armature winding, and said semiconductor diode has its cathode connected between the field winding and armature winding and is thereby connected in series with said motor armature winding and the source. 13 An electrical motor control system comprising: a direct current power source having a positive and a negative terminal, a saturable core transformer having two windings with a common terminal and so wound as to have induced voltages of opposite polarities at their ends opposite said terminal when there is a change in electrical current flowing between these ends, a condenser connected in series with the end of one of said winding and the negative terminal of said power source, a direct current motor including an armature connected in series between the end of the other of said windings and the positive terminal of said power source, an inductance connected between the armature of said motor and said end of the other of said windings, a semiconductor diode having its cathode connected between said armature and said inductance and said diode connected in series between said armature and said power source, a silicon controlled rectifier connected in parallel with said condenser with its anode connected to the common terminal on said transformer, control means for cyclically turning said silicon controlled rectifier on in response to the voltage at the common terminal of the transformer when said voltage is positive with respect to the cathode of said silicon controlled rectifier, means for turning said silicon controlled rectifier off in response to the voltage at the common terminal of said transformer being negative with respect to the cathode of said silicon controlled rectifier, whereby said direct current motor is energized by unidirectional pulses of electrical current.
Claim 14
Dependent Claim
21 words
An electrical motor control system as claimed in claim 13 in which said saturable core transformer has a square hysteresis loop.
Claim 15
Dependent Claim
43 words
An electrical motor control system as claimed in claim 13 including: a semiconductor diode having a relatively slow reverse recovery characteristic connected in series with said motor and said direct current power source and in reverse bias direction relative to said power source.
Claim 16
Dependent Claim
55 words
An electrical motor control system as claimed in claim 13 in which: said saturable core transformer has a square hysteresis loop, and including: a semiconductor diode having a relatively slow reverse recovery characteristic connected in series with said motor and said direct current power source and in reverse bias direction relative to said power source.
Claim 17
Dependent Claim
51 words
An electrical motor control system as claimed in claim 13 in which: said control means comprises an adjustable trigger circuit adapted to cyclically turn on the silicon controlled rectifier, and said means for turning said switching device off is a commutating circuit including one winding of said transformer and said condenser.
Claim 18
Dependent Claim
29 words
An electrical motor control system as claimed in claim 16 in which: said control means comprises an adjustable trigger circuit adapted to cyclically turn on the silicon controlled rectifier.
Claim 19
Dependent Claim
36 words
An electrical motor control system as claimed in claim 18 in which: said adjustable trigger circuit includes an adjustable resistor and a condenser in series with each other and in parallel with said silicon controlled rectifier.
Claim 20
Dependent Claim
20 words
An electrical motor control system as claimed in claim 19 in which: said adjustable trigger circuit includes a unijunction transistor.
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) | 1974-04-19 | 1974-10-19 | 1975-04-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-04-19 | 1978-10-19 | 1979-04-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-04-19 | 1982-10-19 | 1983-04-20 | $7700.00 | Window Closed / Lapsed |