Patent US3569806A successfully refreshed from Google Patents.
US3569806A
Expired / Lapsed
US
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Starting arrangement for solid-state commutated motor
Assignee: Brailsford and Co Inc
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Filing: 1968-10-08
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Granted: 1971-03-09
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Expires: 1988-10-08
Abstract
Abstract A circuit comprising a solid-state commutating means in an oscillatory circuit for a direct current motor. The circuit includes photosensitive means actuated by electric light means gated by the rotor and connected to modify the feedback as the amount of illumination striking the photosensitive means varies in response to the gating. The change in feedback controls the current in the circuit to provide proper starting and running currents. In particular the solid-state commutating means may be in the form of a circuit similar to a flip-flop with separate stator coils in series with the active elements of the flip-flop and with feedback resistors connecting the output of one part of the flip-flop to the input of the other. The photosensitive means include photoconductive cells connected to change the effective impedance of the feedback resistors and means may be included so that, after the motor has gotten started, the amount of current through the electric light may be reduced to a value too low to cause incandescence or the current may even be turned off entirely.
Inventors
- 👤 Harrison D Brailsford
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 12:23
CPC Classifications
H; H02; H02K; H02K29/00; H02K29/06; H02K29/10
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
266 words
A motor comprising: a. a permanent magnetic rotor having an even number of equally spaced magnetized pole areas; b. a stator comprising a ferromagnetically soft member having an even number of stator poles; c. first and second stator windings on said member to induce magnetic flux in said poles in predetermined polarities when electric current flows in a predetermined direction in said windings; d. a solid-state commutator circuit comprising first and second solid-state devices each having an output section connected in series with said first and second windings, respectively, and an input section, and a feedback circuit comprising a first impedance connecting the output section of said first solidstate device to the input section of said second solid-state device and a second impedance connecting to the input section of said first solid-state device to cause said commutator circuit to be self-oscillatory; e. electric light means; f. first and second photocell means connected to said first and second impedances, respectively, to change the feedback when illumination from said light means strikes said photocell; and g. barrier means attached to said rotor to rotate therewith and located to traverse a path between said light means and said photocell means as said rotor rotates, said barrier comprising edges defining an opening fixed with respect to said rotor poles areas, said stator poles, and said photocell means to permit light from said light means to strike one of said photocell means at any stopping position of said rotor whereby said one of said photocell means will be actuated by said light to energize said stator windings to start said rotor.
Claim 2
Dependent Claim
266 words
A motor comprising: a. a permanent magnetic rotor having an even number of equally spaced magnetized pole areas; b. a stator comprising a ferromagnetically soft member having an even number of stator poles; c. first and second stator windings on said member to induce magnetic flux in said poles in predetermined polarities when electric current flows in a predetermined direction in said windings; d. a solid-state commutator circuit comprising first and second solid-state devices each having an output section connected in series with said first and second windings, respectively, and an input section, and a feedback circuit comprising a first impedance connecting the output section of said first solidstate device to the input section of said second solid-state device and a second impedance connecting to the input section of said first solid-state device to cause said commutator circuit to be self-oscillatory; e. electric light means; f. first and second photocell means connected to said first and second impedances, respectively, to change the feedback when illumination from said light means strikes said photocell; and g. barrier means attached to said rotor to rotate therewith and located to traverse a path between said light means and said photocell means as said rotor rotates, said barrier comprising edges defining an opening fixed with respect to said rotor poles areas, said stator poles, and said photocell means to permit light from said light means to strike one of said photocell means at any stopping position of said rotor whereby said one of said photocell means will be actuated by said light to energize said stator windings to start said rotor.
Claim 3
Dependent Claim
114 words
The motor of claim 1 in which: a. said barrier traverses a circular path and comprises first and second sections each intercepting an angle of approximately 90* from the center of said path, said sections being located on substantially diametrically opposite sides of said center; and b. said photocells are angularly spaced substantially 90* apart around said circular path whereby light from said light means is divided by said barrier sections into pulses of light reaching said photocells, each of said photocells receiving two pulses of light per revolution of said barrier, the pulses of light reaching said first photocell substantially only during intervals when pulses of light are not reaching said second photocell.
Claim 4
Dependent Claim
23 words
The motor of claim 2 in which said photocells are photoconductive and are connected, respectively, in parallel with said first and second impedances.
Claim 5
Dependent Claim
38 words
The motor of claim 3 in which said light means comprising an incandescent lamp connected electrically in series with said stator windings, whereby the sum of current flowing in said first and second windings flows through said lamp.
Claim 6
Dependent Claim
20 words
The motor of claim 4 comprising in addition a solid-state voltage limiting device connected directly in parallel with said lamp.
Claim 7
Dependent Claim
110 words
The motor of claim 2 comprising, in addition: a. a transistor having an output section connected in series with said light means as a first series circuit; and b. a resistor and capacitor connected in series as a second series circuit in parallel with said first series circuit, said transistor comprising an input section connected to said second series circuit whereby said transistor will be conductive from the time a voltage is applied across said first and second series circuits until the voltage at the junction of said resistor and capacitor reaches a predetermined level and makes said transistor nonconductive to halt the flow of current through said light means.
References Cited (Backward Citations)
US3204165A
Cited
US3299335A
Cited
US3345547A
Cited
US3377534A
Cited
US3412303A
Cited
US3453514A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-03-08 | 1974-09-07 | 1975-03-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-08 | 1978-09-07 | 1979-03-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-08 | 1982-09-07 | 1983-03-09 | $7700.00 | Window Closed / Lapsed |