US3706024A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Tap changing apparatus having a gate control tripper
Assignee: Westinghouse Electric Corp
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Filing: 1971-03-29
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Granted: 1972-12-12
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Expires: 1991-03-29
Abstract
Abstract Tap changing apparatus including a transformer having a tapped winding, solid state switching elements connected between the winding and a load, and a control circuit which provides the proper gate drive to the switching elements for changing taps. The control circuit senses the voltage and current characteristics of the system to determine at what instant it will gate the switching elements in making a tap change. A tripper circuit senses the system current and trips the control circuit so that a tap change cannot be made when the system current is too low to have its characteristics detected.
Inventors
- 👤 Peter Wood
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 02:17
CPC Classifications
H; H01; H01F; H01F29/00; H01F29/02
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
79 words
Solid state tap changing apparatus comprising solid state switching means, gate control means which controls said switching means, system current sensing means, gate control tripping means having input and output terminals, the output terminals of said tripping means being connected to said gate control means, said tripping means preventing said gate control means from making a tap change when the amplitude of the system current is below a first predetermined value for substantially one-half cycle of the system current.
Claim 2
Dependent Claim
79 words
Solid state tap changing apparatus comprising solid state switching means, gate control means which controls said switching means, system current sensing means, gate control tripping means having input and output terminals, the output terminals of said tripping means being connected to said gate control means, said tripping means preventing said gate control means from making a tap change when the amplitude of the system current is below a first predetermined value for substantially one-half cycle of the system current.
Claim 3
Dependent Claim
47 words
The solid state tap changing apparatus of claim 1 wherein the tripping means does not permit the gate control means to reacquire tap changing control, after it has been prevented from making tap changes, until the amplitude of the system current increases to a second predetermined value.
Claim 4
Dependent Claim
59 words
The solid state tap changing apparatus of claim 1 wherein a full wave rectified voltage, which is proportional to the system current, is applied to the input terminals of the tripping means, and two of the output terminals of the tripping means provide a voltage which changes polarity when the first predetermined value of system current amplitude is sensed.
Claim 5
Dependent Claim
220 words
Solid state tap changing apparatus comprising solid state switching means, gate control means which controls said switching means, system current sensing means, gate control tripping means having input and output terminals, the output terminals of said tripping means being connected to said gate control means, said tripping means preventing said gate control means from making a tap change when the amplitude of the system current is below a first predetermined value for substantially one-half of the system current, said tripping means preventing the gate control means from reacquiring tap changing control until the amplitude of the system current increases to a second predetermined value, said tripping means comprising a solid state transistor element, a capacitor and a resistor serially connected across a source of DC potential, said transistor being controlled by a voltage proportional to the system current, said transistor causing the charge on said capacitor to decrease when the system current maintains an amplitude above said first predetermined value during substantially one-half cycle of the system current, comparator means having an output terminal and first and second input terminals, said first input terminal being connected to said capacitor, and said second input terminal being connected in such a manner as to receive a voltage having the same polarity as the voltage at said output terminal of said comparator means.
Claim 6
Dependent Claim
220 words
Solid state tap changing apparatus comprising solid state switching means, gate control means which controls said switching means, system current sensing means, gate control tripping means having input and output terminals, the output terminals of said tripping means being connected to said gate control means, said tripping means preventing said gate control means from making a tap change when the amplitude of the system current is below a first predetermined value for substantially one-half of the system current, said tripping means preventing the gate control means from reacquiring tap changing control until the amplitude of the system current increases to a second predetermined value, said tripping means comprising a solid state transistor element, a capacitor and a resistor serially connected across a source of DC potential, said transistor being controlled by a voltage proportional to the system current, said transistor causing the charge on said capacitor to decrease when the system current maintains an amplitude above said first predetermined value during substantially one-half cycle of the system current, comparator means having an output terminal and first and second input terminals, said first input terminal being connected to said capacitor, and said second input terminal being connected in such a manner as to receive a voltage having the same polarity as the voltage at said output terminal of said comparator 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) | 1975-12-12 | 1976-06-12 | 1976-12-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-12-12 | 1980-06-12 | 1980-12-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-12-12 | 1984-06-12 | 1984-12-12 | $7700.00 | Window Closed / Lapsed |