US4901005A
Expired / Lapsed
US
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Zero voltage crossover detector for polyphase systems
Assignee: International Business Machines Corp
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Filing: 1988-12-05
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Granted: 1990-02-13
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Expires: 2008-12-05
Abstract
Abstract The invention finds application primarily in three phase power systems having A, B and C voltage phases. The invention includes a first voltage measurement device coupled between the A phase input and the B phase input, having a first measured voltage output. The invention further includes a second voltage measurement device coupled between the A phase input and the C phase input, having a second measured voltage output. The invention also includes a comparator having a first input connected to the first output of the first voltage measurement device and a second input connected to the second output of the second voltage measurement device, for generating a signal when the first measured voltage is equal to and opposite in polarity from the second measured voltage. This signal indicates that a zero crossover event has occurred with the A phase.
Inventors
- 👤 Charles H. Shin
- 👤 George K. Woodworth
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 16:40
CPC Classifications
G; G01; G01R; G01R19/00; G01R19/175
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
158 words
A zero voltage crossover detector for a three phase power system, having A, B and C voltage phase inputs, comprising: a first voltage measurement means connected between said A phase input and said B phase input, having a first measured voltage output, for measuring the voltage between said A phase input and said B phase input; a second voltage measurement means connected between said A phase input and said C phase input, having a second measured voltage output, for measuring the voltage between said A phase input and said C phase input; a comparator means having a first input connected to said first output of said first voltage measurement means and a second input connected to said second output of said second voltage measurement means, for generating a signal when said first measured voltage is substantially equal in magnitude and opposite in polarity from said second measured voltage, indicating a zero voltage crossover event for said A phase.
Claim 2
Dependent Claim
158 words
A zero voltage crossover detector for a three phase power system, having A, B and C voltage phase inputs, comprising: a first voltage measurement means connected between said A phase input and said B phase input, having a first measured voltage output, for measuring the voltage between said A phase input and said B phase input; a second voltage measurement means connected between said A phase input and said C phase input, having a second measured voltage output, for measuring the voltage between said A phase input and said C phase input; a comparator means having a first input connected to said first output of said first voltage measurement means and a second input connected to said second output of said second voltage measurement means, for generating a signal when said first measured voltage is substantially equal in magnitude and opposite in polarity from said second measured voltage, indicating a zero voltage crossover event for said A phase.
Claim 3
Independent Claim
117 words
A method for detecting zero voltage crossover for a three phase power system, having A, B and C voltage phase inputs, comprising the steps of: measuring a first voltage between said A voltage phase input and said B voltage phase input and producing a first measured voltage output; measuring a second voltage between said A voltage phase input and said C voltage phase input and producing a second measured voltage output; comparing said first measured voltage output to said second measured voltage output and generating a signal when said first measured voltage is substantially equal in magnitude and opposite in polarity from said second measured voltage, indicating a zero voltage crossover event for said A voltage phase.
Claim 4
Independent Claim
117 words
A method for detecting zero voltage crossover for a three phase power system, having A, B and C voltage phase inputs, comprising the steps of: measuring a first voltage between said A voltage phase input and said B voltage phase input and producing a first measured voltage output; measuring a second voltage between said A voltage phase input and said C voltage phase input and producing a second measured voltage output; comparing said first measured voltage output to said second measured voltage output and generating a signal when said first measured voltage is substantially equal in magnitude and opposite in polarity from said second measured voltage, indicating a zero voltage crossover event for said A voltage phase.
Claim 5
Dependent Claim
458 words
A zero voltage crossover detector for a three phase power system, having A, B and C voltage phase inputs, comprising: a first transformer having a first primary coil connected between said A voltage phase input and a common node, and further having a first secondary coil with a first terminal at a first end having a positive voltage when said A voltage phase is positive, a second terminal at an opposed second end having a negative voltage when said A voltage phase is positive, and a center tap connected to ground potential; a second transformer having a second primary coil connected between said B voltage phase input and said common node, and further having a second secondary coil with a first terminal at a first end having a positive voltage when said B voltage phase is positive, a second terminal at an opposed second end having a negative voltage when said B voltage phase is positive, and a center tap connected to ground potential; a third transformer having a third primary coil connected between said C voltage phase input and said common node, and further having a third secondary coil with a first terminal at a first end having a positive voltage when said C voltage phase is positive, a second terminal at an opposed second end having a negative voltage when said C voltage phase is positive, and a center tap connected to ground potential; a first voltage comparator means having a first input connected to said second terminal of said second secondary coil and having a second input connected to said first terminal of said third secondary coil, for generating a first output signal when said first input thereof has a voltage substantially equal in magnitude and opposite in polarity from a voltage on said second input thereof, indicating a zero voltage crossover event for said A phase; a second voltage comparator means having a first input connected to said second terminal of said third secondary coil and having a second input connected to said first terminal of said first secondary coil, for generating a second output signal when said first input thereof has a voltage substantially equal in magnitude and opposite in polarity from a voltage on said second input thereof, indicating a zero voltage crossover event for said B phase; a third voltage comparator means having a first input connected to said second terminal of said first secondary coil and having a second input connected to said first terminal of said second secondary coil, for generating a third output signal when said first input thereof has a voltage substantially equal in magnitude and opposite in polarity from a voltage on said second input thereof, indicting a zero voltage crossover event for said C phase.
Claim 6
Dependent Claim
458 words
A zero voltage crossover detector for a three phase power system, having A, B and C voltage phase inputs, comprising: a first transformer having a first primary coil connected between said A voltage phase input and a common node, and further having a first secondary coil with a first terminal at a first end having a positive voltage when said A voltage phase is positive, a second terminal at an opposed second end having a negative voltage when said A voltage phase is positive, and a center tap connected to ground potential; a second transformer having a second primary coil connected between said B voltage phase input and said common node, and further having a second secondary coil with a first terminal at a first end having a positive voltage when said B voltage phase is positive, a second terminal at an opposed second end having a negative voltage when said B voltage phase is positive, and a center tap connected to ground potential; a third transformer having a third primary coil connected between said C voltage phase input and said common node, and further having a third secondary coil with a first terminal at a first end having a positive voltage when said C voltage phase is positive, a second terminal at an opposed second end having a negative voltage when said C voltage phase is positive, and a center tap connected to ground potential; a first voltage comparator means having a first input connected to said second terminal of said second secondary coil and having a second input connected to said first terminal of said third secondary coil, for generating a first output signal when said first input thereof has a voltage substantially equal in magnitude and opposite in polarity from a voltage on said second input thereof, indicating a zero voltage crossover event for said A phase; a second voltage comparator means having a first input connected to said second terminal of said third secondary coil and having a second input connected to said first terminal of said first secondary coil, for generating a second output signal when said first input thereof has a voltage substantially equal in magnitude and opposite in polarity from a voltage on said second input thereof, indicating a zero voltage crossover event for said B phase; a third voltage comparator means having a first input connected to said second terminal of said first secondary coil and having a second input connected to said first terminal of said second secondary coil, for generating a third output signal when said first input thereof has a voltage substantially equal in magnitude and opposite in polarity from a voltage on said second input thereof, indicting a zero voltage crossover event for said C phase.
Claim 7
Dependent Claim
236 words
A zero voltage crossover detector for a three phase power system, having A, B and C voltage phase inputs, comprising: a first transformer having a first primary coil connected between said A voltage phase input and a common node, and further having a first secondary coil with a first terminal at a first end having a positive voltage when said A voltage phase is positive, a second terminal at an opposed second end having a negative voltage when said A voltage phase is positive, and a center tap connected to ground potential; a second transformer having a second primary coil connected between said B voltage phase input and said common node, and further having a second secondary coil with a first terminal t a first end having a positive voltage when said B voltage phase is positive, a second terminal at an opposed second end having a negative voltage when said B voltage phase is positive, and a center tap connected to ground potential; a voltage comparator ;means having a first input connected to said second terminal of said first secondary coil and having a second input connected to said first terminal of said second secondary coil, for generating an output signal when said first input thereof has a voltage substantially equal in magnitude and opposite in polarity from a voltage on said second input thereof, indicating a zero voltage crossover event for said C phase.
Claim 8
Dependent Claim
236 words
A zero voltage crossover detector for a three phase power system, having A, B and C voltage phase inputs, comprising: a first transformer having a first primary coil connected between said A voltage phase input and a common node, and further having a first secondary coil with a first terminal at a first end having a positive voltage when said A voltage phase is positive, a second terminal at an opposed second end having a negative voltage when said A voltage phase is positive, and a center tap connected to ground potential; a second transformer having a second primary coil connected between said B voltage phase input and said common node, and further having a second secondary coil with a first terminal t a first end having a positive voltage when said B voltage phase is positive, a second terminal at an opposed second end having a negative voltage when said B voltage phase is positive, and a center tap connected to ground potential; a voltage comparator ;means having a first input connected to said second terminal of said first secondary coil and having a second input connected to said first terminal of said second secondary coil, for generating an output signal when said first input thereof has a voltage substantially equal in magnitude and opposite in polarity from a voltage on said second input thereof, indicating a zero voltage crossover event for said C phase.
References Cited (Backward Citations)
US4313146A
Cited
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1993-02-12 | 1993-08-14 | 1994-02-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-02-12 | 1997-08-14 | 1998-02-13 | $3760.00 | Window Closed / Lapsed |
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