Patent US4389640A successfully refreshed from Google Patents.
US4389640A
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US
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Apparatus for detecting loss of AC power supply and loss of current
Assignee: SUTHERLAND-SCHULTZ Ltd 859 COURTLAND AVE EAST KITCHENER ONTARIO N2G 4H5 CANADA A Co OF ONTARIO
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Filing: 1981-03-31
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Granted: 1983-06-21
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Expires: 2001-03-31
Abstract
Abstract Apparatus for detecting loss of AC power supply for an electrical conductor and loss of current through the electrical conductor when the power supply is connected thereto comprises voltage responsive means operable to produce a voltage present signal when the power supply is connected to the electrical conductor and a predetermined voltage is present across the conductor and a voltage absent signal when the predetermined voltage is not present across the conductor, and current responsive means operable to produce a current present signal when a predetermined current is flowing through the conductor and a current absent signal when the predetermined current is not flowing through the conductor. Fault-signalling means is connected to the AC power supply for operation thereby, and means responsive to the simultaneous presence of a voltage present signal and a current present signal and to the simultaneous presence of a voltage absent signal and a current absent signal causes the power supply to operate the fault-signalling means in a no-fault indicating sense. The absence of the AC power supply or the simultaneous presence of an absent signal and a present signal causes the fault-signalling means to indicate a fault condition.
Inventors
- 👤 James E. Dawdy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 13:55
CPC Classifications
G; G01; G01R; G01R19/00; G01R19/165; G01R19/16533; G01R19/16538; G01R19/16547; G01R31/00; G01R31/40; G01R31/42
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
194 words
Apparatus for detecting loss of AC power supply for an electrical conductor and loss of current through the electrical conductor when the power supply is connected thereto, said apparatus comprising voltage responsive means operable to produce a voltage present signal when the power supply is connected to the electrical conductor and a predetermined voltage is present across the conductor and a voltage absent signal when the predetermined voltage is not present across the conductor, current responsive means operable to produce a current present signal when a predetermined current is flowing through the conductor and a current absent signal when the predetermined current is not flowing through the conductor, fault-signalling means connected to said AC power supply for operation thereby, and means responsive to the simultaneous presence of a voltage present signal and a current present signal and to the simultaneous presence of a voltage absent signal and a current absent signal to cause the power supply to operate the fault-signalling means in a no-fault indicating sense, the absence of said AC power supply or the simultaneous presence of an absent signal and a present signal causing the fault-signalling means to indicate a fault condition.
Claim 2
Dependent Claim
194 words
Apparatus for detecting loss of AC power supply for an electrical conductor and loss of current through the electrical conductor when the power supply is connected thereto, said apparatus comprising voltage responsive means operable to produce a voltage present signal when the power supply is connected to the electrical conductor and a predetermined voltage is present across the conductor and a voltage absent signal when the predetermined voltage is not present across the conductor, current responsive means operable to produce a current present signal when a predetermined current is flowing through the conductor and a current absent signal when the predetermined current is not flowing through the conductor, fault-signalling means connected to said AC power supply for operation thereby, and means responsive to the simultaneous presence of a voltage present signal and a current present signal and to the simultaneous presence of a voltage absent signal and a current absent signal to cause the power supply to operate the fault-signalling means in a no-fault indicating sense, the absence of said AC power supply or the simultaneous presence of an absent signal and a present signal causing the fault-signalling means to indicate a fault condition.
Claim 3
Dependent Claim
45 words
Apparatus according to claim 1 wherein the fault-signalling means comprises a visual device which is operated in one manner by current from the AC power supply in the no-fault condition and through which no current flows in the fault condition to thereby indicate a fault.
Claim 4
Dependent Claim
92 words
Apparatus according to claim 1 wherein the fault-signalling means comprises a relay coil through which current flows from the AC power supply in the no-fault condition and through which no current flows in a fault condition, and the apparatus also includes alarm means operable by an electrical power source independent of said AC power supply, the alarm means including a relay contact opened by the relay coil when current is flowing therethrough, said relay contact being closed when no current flows through the relay coil to cause operation of said alarm means.
Claim 5
Dependent Claim
55 words
Apparatus according to claim 1 wherein said voltage responsive means includes means to produce pulses when said predetermined voltage is present across the electrical conductor and a missing pulse detector operable to produce said voltage present signal when said pulses are present and to produce said voltage absent signal when said pulses are not present.
Claim 6
Dependent Claim
20 words
Apparatus according to claim 4 wherein said missing pulse detector is coupled to the pulse producing means by opto-coupling means.
Claim 7
Dependent Claim
62 words
Apparatus according to claim 1 wherein said current responsive means includes means to produce and transmit pulses pulses only when said predetermined current is flowing through the conductor and a missing pulse detector operable to receive transmitted pulses and produce said current present signal when said pulses are present and to produce said current absent signal when said pulses are not present.
Claim 8
Dependent Claim
53 words
Apparatus according to claim 6 wherein said current responsive means includes means operable to produce pulses whose amplitude is indicative of the value of the current in the conductor and means to transmit to the missing pulse detector only those pulses indicative of current of at least the predetermined value in the conductor.
Claim 9
Dependent Claim
19 words
Apparatus according to claim 7 wherein the pulse producing means passes only negative pulses to the pulse transmitting means.
Claim 10
Dependent Claim
26 words
Apparatus according to claim 7 wherein said pulse producing means is adjustable to vary the value of the predetermined current which produces a current present signal.
Claim 11
Dependent Claim
30 words
Apparatus according to claim 9 wherein said pulse producing means comprises a first variable amplification stage and a second stage which passes only negative pulses to the pulse transmitting means.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-06-20 | 1986-12-20 | 1987-06-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-06-20 | 1990-12-20 | 1991-06-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-06-20 | 1994-12-20 | 1995-06-21 | $7700.00 | Window Closed / Lapsed |