Patent US21255A successfully refreshed from Google Patents.
Patent US3848166A successfully refreshed from Google Patents.
US3848166A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Silicon controlled rectifier type inverter for electric motors
Assignee: LOUIS W PARKER TRUSTEE
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Filing: 1973-01-22
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Granted: 1974-11-12
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Expires: 1993-01-22
Abstract
Abstract The current through a load, e.g., the stator coil of a synchronous type electric motor, is periodically reversed in direction by an inverter employing a plurality of silicon controlled rectifiers (SCR''s). The SCR''s are associated with one another in pairs, at opposing ends of the load respectively; and the direction of current flow through the load is controlled by rendering a selected pair of SCR''s conductive, to effect current flow through the load or stator coil in a first direction, and by then shutting off the current flow through said selected pair and rendering a different pair of SCR''s conductive to effect current flow in the opposite direction through said load. Current flowing through a selected pair of SCR''s is shut off by connecting a charged capacitor across one of the conducting SCR''s in said selected pair, the capacitor charge polarity being such as to initially promote current flow therethrough. Connection of the charged capacitor in this fashion effects a reversal of the charge polarity across the capacitor; and the reversely charged capacitor is thereafter connected across a conducting SCR in the other of said SCR pairs when it is desired to interrupt current flow through said other pair of SCR''s.
Inventors
- 👤 J Jamieson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 22:40
CPC Classifications
H; H02; H02P; H02P6/00; H02P6/14
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
319 words
In combination, an electric motor having a rotor and at least one stator coil, a bridgetype current inverter connected to said motor, said inverter comprising first and second pairs of silicon controlled rectifiers connected to said stator coil of said motor, said first pair of rectifiers being poled in like direction to one another and in opposite direction to said second pair of rectifiers relative to said stator coil whereby conduction of said first pair of rectifiers effects current flow via said first pair in a first direction through said stator coil and conduction Of said second pair of rectifiers effects current flow via said second pair in the opposite direction through said stator coil, said reversals in stator coil current flow direction cooperating with said rotor to produce a torque between said stator coil and rotor operative to effect rotary movement of said rotor, first control means coupled to each of the rectifiers in said first and second pairs of rectifiers for rendering alternate ones of said pairs of rectifiers conductive during alternate mutually exclusive periods of time, second control means operative during time intervals between said periods of time for shutting off the conducting pair of said rectifiers, said second control means including a capacitor, and selectively operable switch means for connecting said capacitor across one of the rectifiers in the conducting pair of said rectifiers, said first and second control means comprising a rotary commutator connected to the rotor of said motor and driven thereby, said commutator having a plurality of outputs which are energized at a rate and in a sequence determined by the rotation of said motor rotor, and means coupling said plurality of sequentially energized outputs to said switch means and to the gate electrodes of each of the rectifiers in said first and second pairs of rectifiers in a predetermined sequence to control the operating states of said switch means and rectifiers.
Claim 2
Dependent Claim
319 words
In combination, an electric motor having a rotor and at least one stator coil, a bridgetype current inverter connected to said motor, said inverter comprising first and second pairs of silicon controlled rectifiers connected to said stator coil of said motor, said first pair of rectifiers being poled in like direction to one another and in opposite direction to said second pair of rectifiers relative to said stator coil whereby conduction of said first pair of rectifiers effects current flow via said first pair in a first direction through said stator coil and conduction Of said second pair of rectifiers effects current flow via said second pair in the opposite direction through said stator coil, said reversals in stator coil current flow direction cooperating with said rotor to produce a torque between said stator coil and rotor operative to effect rotary movement of said rotor, first control means coupled to each of the rectifiers in said first and second pairs of rectifiers for rendering alternate ones of said pairs of rectifiers conductive during alternate mutually exclusive periods of time, second control means operative during time intervals between said periods of time for shutting off the conducting pair of said rectifiers, said second control means including a capacitor, and selectively operable switch means for connecting said capacitor across one of the rectifiers in the conducting pair of said rectifiers, said first and second control means comprising a rotary commutator connected to the rotor of said motor and driven thereby, said commutator having a plurality of outputs which are energized at a rate and in a sequence determined by the rotation of said motor rotor, and means coupling said plurality of sequentially energized outputs to said switch means and to the gate electrodes of each of the rectifiers in said first and second pairs of rectifiers in a predetermined sequence to control the operating states of said switch means and rectifiers.
Claim 3
Dependent Claim
34 words
The combination of claim 1 including means for charging said capacitor, said switch means being operative to connect said charged capacitor across said one of said rectifiers in the conducting pair of said rectifiers.
Claim 4
Dependent Claim
99 words
The combination of claim 2 wherein one of said first pair of rectifiers has its cathode connected to one end of said motor stator coil and one of said second pair of rectifiers has its anode connected to said one end of said stator coil, one side of said capacitor being connected to said one end of said stator coil, said switch means including means for selectively connecting the other side of said capacitor to the anode of said one of said first pair of rectifiers or to the cathode of said one of said second pair of rectifiers.
Claim 5
Dependent Claim
96 words
The combination of claim 3 wherein said switch means comprises third silicon controlled rectifier means connected between the other side of said capacitor and the anode of said one of said first pair of rectifiers and fourth silicon controlled rectifier means connected between the other side of said capacitor and the cathode of said one of said second pair of rectifiers, said commutator including outputs coupled to the gate electrodes of said third and fourth silicon controlled rectifier means for rendering alternate ones of said third and fourth rectifier means conductive during alternate spaced time intervals.
Claim 6
Dependent Claim
30 words
The combination of claim 1 wherein said commutator comprises a rotary member affixed to the rotor shaft of said motor and having a plurality of brushes in mechanical engagement therewith.
Claim 7
Dependent Claim
15 words
The combination of claim 1 wherein said commutator comprises means producing a rotating magnetic field.
Claim 8
Dependent Claim
12 words
The combination of claim 1 wherein said commutator comprises a photoelectric commutator.
Claim 9
Dependent Claim
24 words
The combination of claim 1 wherein said commutator includes an audio frequency oscillator the output of which is sequentially connected to said commutator outputs.
Claim 10
Dependent Claim
43 words
The combination of claim 2 wherein said switch means is operative to connect said charged capacitor across said one of said rectifiers with an initial charge polarity which adds to the current flow from said conducting one of said rectifiers through said capacitor.
Claim 11
Dependent Claim
26 words
The combination of claim 1 wherein said motor rotor comprises a coil winding, and means for producing a unidirectional current flow through said rotor coil winding.
Claim 12
Dependent Claim
32 words
The combination of claim 1 wherein said motor rotor comprises a coil winding connected in series circuit with a unidirectional power source, said series circuit being connected across said bridge-type curRent inverter.
Claim 13
Dependent Claim
25 words
The combination of claim 11 wherein said series circuit includes a variable resistance for controlling the magnitude of current flow through said rotor coil winding.
Claim 14
Dependent Claim
59 words
The combination of claim 1 wherein said motor rotor comprises at least one coil winding connected to both of said pairs of rectifiers, conduction of said first pair of rectifiers being operative to effect current flow through said coil winding in the same direction as is effected through said coil winding by conduction of said second pair of rectifiers.
Claim 15
Dependent Claim
36 words
The combination of claim 1 wherein said inverter includes a variable resistance in series with at least one of said pairs of rectifiers for controlling the effective impedance of said one pair to current flow therethrough.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-11-11 | 1978-05-13 | 1978-11-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-11-11 | 1982-05-13 | 1982-11-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-11-11 | 1986-05-13 | 1986-11-12 | $7700.00 | Window Closed / Lapsed |