US3681636A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Phase sequence sensing circuit
Assignee: Westinghouse Electric Corp
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Filing: 1969-08-14
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Granted: 1972-08-01
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Expires: 1989-08-14
Abstract
Abstract In a polyphase AC power system, application of power to a load only upon correct phase sequence is provided by a circuit including a semiconductor switch such as a thyristor for directly developing a signal for an electrically responsive circuit closure means by the sequence of phase voltages on its control and main electrodes.
Inventors
- 👤 Wendell Calfee
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 10:09
CPC Classifications
H; H02; H02H; H02H11/00; H02H11/004
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
147 words
A circuit for sensing phase sequence of voltages in an AC polyphase system comprising: a first semiconductor switching means having a control electrode and a pair of main electrodes; means for applying a first voltage representing at least a first phase voltage to said control electrode; means for applying a second voltage representing an additional phase voltage to one of said main electrodes while the other of said main electrodes is maintained at a fixed reference potential, said switching means turning on and becoming conducting only when said first and second voltages are present and of the same polarity in relation to said fixed reference potential and remaining on during the time said second voltage is present; electrically responsive circuit closure means coupled between said one main electrode and said additional phase voltage for closing a load circuit only when said phase voltages have a predetermined relation.
Claim 2
Dependent Claim
147 words
A circuit for sensing phase sequence of voltages in an AC polyphase system comprising: a first semiconductor switching means having a control electrode and a pair of main electrodes; means for applying a first voltage representing at least a first phase voltage to said control electrode; means for applying a second voltage representing an additional phase voltage to one of said main electrodes while the other of said main electrodes is maintained at a fixed reference potential, said switching means turning on and becoming conducting only when said first and second voltages are present and of the same polarity in relation to said fixed reference potential and remaining on during the time said second voltage is present; electrically responsive circuit closure means coupled between said one main electrode and said additional phase voltage for closing a load circuit only when said phase voltages have a predetermined relation.
Claim 3
Dependent Claim
48 words
The subject matter of claim 1 wherein: said means for applying a first voltage is coupled to a voltage representing only a first phase voltage and said first voltage is a rectified voltage applied for a full half cycle of the corresponding phase voltage to said control electrode.
Claim 4
Dependent Claim
27 words
The subject matter of claim 1 wherein: said means for applying a first voltage is coupled to a plurality of phase voltages which said first voltage represents.
Claim 5
Dependent Claim
131 words
The subject matter of claim 3 further comprising: a second semiconductor switching means having a control electrode and a pair of main electrodes; means for applying a voltage representing a first phase voltage to said control electrode of said second semiconductor switching means; means for applying a voltage representing a second phase voltage to one of said main electrodes of said second semiconductor switching means; said second semiconductor switching means turning on and becoming conductive only when said voltages are both present and remaining on during the time said voltage is present on said one of said main electrodes; said means for applying a first voltage to said control electrode of said first semiconductor switching device is coupled to the other of said main electrodes of said second semiconductor switching means.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-08-01 | 1976-01-31 | 1976-08-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-01 | 1980-01-31 | 1980-08-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-01 | 1984-01-31 | 1984-08-01 | $7700.00 | Window Closed / Lapsed |