Patent US3314780A successfully refreshed from Google Patents.
Patent US4820964A successfully refreshed from Google Patents.
US4820964A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Solid state motor start circuit
Assignee: KADAH ANDREW S DAEDALUS INDUSTRIAL PARK CICERO NY 13039 A CORP OF NY
•
Filing: 1988-02-19
•
Granted: 1989-04-11
•
Expires: 2008-02-19
Abstract
Abstract A start circuit for a single phase AC induction motor employs an impedance in series with the run winding to develop a voltage drop proportional to the current through the run winding, and a pair of LEDs or another light emitting device across this impedance to produce a light output whose intensity varies with the field current, and hence in a generally inverse relation with motor speed. A solid-state AC current switch, which can be a triac or a pair of back-to-back SCRs, is gated by a photosensitive circuit that includes a photosensitive element. A light conduit, which can be a light pipe or light dome, for example, carries the light output from the light emitting element to the photosensitive element. The device of this circuit is highly reliable, has no mechanical contacts, and is relatively insensitive to temperature and voltage fluctuation.
Inventors
- 👤 Andrew S. Kadah
- 👤 Kenneth G. Frazer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 11:54
CPC Classifications
H; H02; H02P; H02P1/00; H02P1/16; H02P1/42
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
195 words
Start circuit for a single-phase AC induction motor of the type having at least one run winding connected to a pair of AC inputs and a start winding connected with or without as start capacitor to said AC inputs during a start-up operation but which is cut out from said AC inputs when said motor has achieved running speed, the motor also having a thermal cutout switch in series with the run winding that includes a heater resistor in series with said run winding developing a voltage thereacross that varies with the current through the run winding; the start circuit comprising a light emitting diode connected to said heater resistor providing light output whose intensity depends on said voltage; AC current switch means having a gate electrode and having current electrodes in series with said start winding; photosensitive circuit means including a photosensitive element and producing an output signal that depends on the intensity of light incident on the photosensitive element having an output supplying said output signal to the gate electrode of said AC current switch means; and light conduit means carrying said light output from said light emitting diode to said photosensitive element.
Claim 2
Dependent Claim
195 words
Start circuit for a single-phase AC induction motor of the type having at least one run winding connected to a pair of AC inputs and a start winding connected with or without as start capacitor to said AC inputs during a start-up operation but which is cut out from said AC inputs when said motor has achieved running speed, the motor also having a thermal cutout switch in series with the run winding that includes a heater resistor in series with said run winding developing a voltage thereacross that varies with the current through the run winding; the start circuit comprising a light emitting diode connected to said heater resistor providing light output whose intensity depends on said voltage; AC current switch means having a gate electrode and having current electrodes in series with said start winding; photosensitive circuit means including a photosensitive element and producing an output signal that depends on the intensity of light incident on the photosensitive element having an output supplying said output signal to the gate electrode of said AC current switch means; and light conduit means carrying said light output from said light emitting diode to said photosensitive element.
Claim 3
Dependent Claim
30 words
Start circuit as defined in claim 1 wherein said light emitting diode includes a pair of back-to-back coupled LEDs connected across said impedance means or incandescent lamp or the like.
Claim 4
Dependent Claim
25 words
Start circuit as defined in claim 1 wherein said light conduit means includes a light dome containing said light emitting diode and said photosensitive element.
Claim 5
Dependent Claim
24 words
Start circuit as defined in claim 2 wherein said AC current switch is a bidirectional solid-state device or pair of inverse parallel unidirectional devices.
Claim 6
Dependent Claim
25 words
Start circuit as defined in claim 1 wherein said AC current switch is a triac having a pair of current-carrying electrodes and a gate electrode.
Claim 7
Dependent Claim
48 words
Start circuit as defined in claim 5 wherein said photosensitive circuit means includes a photoresistor and an (optional) resistor forming a series circuit across the current carrying electrodes of the triac, with a junction therebetween forming said output electrode and connected to the gate electrode of the triac.
Claim 8
Dependent Claim
75 words
Start circuit as defined in claim 5 wherein said photosensitive circuit means includes a pair of photodiodes connected back-to-back in series with a pair of resistors, the pair of photodiodes being disposed between said pair of resistors, each of the resistors being coupled to a current carrying electrode of said triac, the junction of one of said resistors with said photodiodes forming said output electrode that is connected to the gate electrode of the triac.
Claim 9
Dependent Claim
32 words
Start circuit as defined in claim 1 wherein said light emitting means includes a LED and rectifier circuit means coupled across said impedance means to supply a DC current to said LED.
Claim 10
Dependent Claim
189 words
Start circuit for actuating an AC induction motor of the type having at least one run winding coupled to an AC input and a thermal cutout switch having a heater resistor in series with said run winding, the start circuit comprising: AC current switch means having current electrodes in series with said AC powered device and a gate electrode; and gating means having an input coupled to said heater resistor and an output coupled to the gate electrode of said AC current switch for supplying an output signal to said gate electrode that depends on the voltage across said heater resistor in which said gating means includes a light emitting diode coupled to said heater resistor to light when the current therethrough is above a predetermined value; photosensitive circuit means including a photosensitive element and producing an output signal that is switched on or off in accordance with the intensity of light incident thereon and having an output supplying said output signal to the gate electrode of said AC current switch means; and light conduit means carrying a light output from said light emitting diode to said photosensitive element.
Claim 11
Dependent Claim
189 words
Start circuit for actuating an AC induction motor of the type having at least one run winding coupled to an AC input and a thermal cutout switch having a heater resistor in series with said run winding, the start circuit comprising: AC current switch means having current electrodes in series with said AC powered device and a gate electrode; and gating means having an input coupled to said heater resistor and an output coupled to the gate electrode of said AC current switch for supplying an output signal to said gate electrode that depends on the voltage across said heater resistor in which said gating means includes a light emitting diode coupled to said heater resistor to light when the current therethrough is above a predetermined value; photosensitive circuit means including a photosensitive element and producing an output signal that is switched on or off in accordance with the intensity of light incident thereon and having an output supplying said output signal to the gate electrode of said AC current switch means; and light conduit means carrying a light output from said light emitting diode to said photosensitive element.
Claim 12
Dependent Claim
23 words
Start circuit as defined in claim 1 wherein said heater resistor is in series with said run winding but not said start winding.
References Cited (Backward Citations)
US3071719A
Cited
US3320505A
Cited
US3365639A
Cited
US3549970A
Cited
US3539892A
Cited
US3543090A
Cited
US3728606A
Cited
US3846683A
Cited
US3916274A
Cited
US4197532A
Cited
US4276506A
Cited
US4463304A
Cited
US4574229A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-04-10 | 1992-10-10 | 1993-04-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-04-10 | 1996-10-10 | 1997-04-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-04-10 | 2000-10-10 | 2001-04-11 | $7700.00 | Window Closed / Lapsed |