US3671830A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Single phase motor starting control apparatus
Assignee: AO Smith Corp
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Filing: 1970-06-24
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Granted: 1972-06-20
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Expires: 1990-06-24
Abstract
Abstract A starting circuit for a single phase electric motor, particularly a capacitor start motor, is provided that includes a solid state switch connected in series with the motor starting winding and the capacitor for controlling the supply of power to the starting winding in accordance with switching signals that are developed by a triggering circuit one of whose inputs is a signal proportional to the voltage in the starting winding and is produced by means directly electrically connected across the starting winding. The improved reliability of solid state switching is provided as compared with mechanical relays as has previously been used. Pull in and drop out points may be readily set.
Inventors
- 👤 Andrew P Kruper
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 04:01
CPC Classifications
H; H02; H02P; H02P1/00; H02P1/16; H02P1/42; H02P1/44
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
93 words
In combination: a single phase electric motor having a main winding and a starting winding; a three terminal solid state switch means having a pair of terminals in series circuit connection with said starting winding; a voltage sensing circuit directly connected across said starting winding to develop a first voltage signal proportional to motor speed; a trigger circuit connected to receive said first voltage signal and to apply or remove a switching signal to a third terminal of said solid state switch means only when said first voltage signal is of preDetermined magnitude.
Claim 2
Dependent Claim
93 words
In combination: a single phase electric motor having a main winding and a starting winding; a three terminal solid state switch means having a pair of terminals in series circuit connection with said starting winding; a voltage sensing circuit directly connected across said starting winding to develop a first voltage signal proportional to motor speed; a trigger circuit connected to receive said first voltage signal and to apply or remove a switching signal to a third terminal of said solid state switch means only when said first voltage signal is of preDetermined magnitude.
Claim 3
Dependent Claim
54 words
The combination of claim 1 wherein: said solid state switch means has a characteristic breakdown voltage, in the absence of signal on said gate electrode, that is greater than line voltage used to operate said motor; and further comprising a starting capacitor in series circuit connection with said switch means and said starting winding.
Claim 4
Dependent Claim
15 words
The subject matter of claim 2 wherein: said solid state switch means is a triac.
Claim 5
Dependent Claim
35 words
The subject matter of claim 1 wherein: said means for directly electrically sensing voltage across said starting winding has an output proportional to the speed of the motor regardless of load conditions on said motor.
Claim 6
Dependent Claim
53 words
The subject matter of claim 4 wherein: said output of said voltage sensing circuit is supplied to said trigger circuit and changes the state of the output of said trigger circuit between two potential values that are in inverse relation to voltages from said voltage sensing circuit to which said trigger circuit responds.
References Cited (Backward Citations)
US3421064A
Cited
US3530348A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-06-20 | 1975-12-20 | 1976-06-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-20 | 1979-12-20 | 1980-06-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-20 | 1983-12-20 | 1984-06-20 | $7700.00 | Window Closed / Lapsed |