US4366520A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Differential transformer core for pulse currents
Assignee: Magnetic Metals Corp
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Filing: 1981-03-25
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Granted: 1982-12-28
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Expires: 2001-03-25
Abstract
Abstract A plurality of relatively high magnetic permeability strips are interleaved to form layers of a closed loop differential transformer core. Although the material of each layer by itself may have a relatively square hysteresis loop, the core formed of a plurality of interleaved layers of such material has a substantially more rounded hysteresis loop. Such a core can advantageously be used in a ground fault interruption circuit in which power leads pass through a central opening in the core to form a primary winding and a secondary winding wound on the core may have a capacitor connected in circuit therewith to complete a resonant circuit. By virtue of its more rounded hysteresis loop, the core, in cooperation with the capacitor, permits the establishment of a resonant current in the secondary circuit which is sufficient to trip a circuit breaker after a few cycles of operation of the alternating current or pulsed unidirectional primary current when a small differential current exists between the power leads as a result of a ground fault.
Inventors
- 👤 Guenter B. Finke
- 👤 Bao-Min Ma
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 14:09
CPC Classifications
H; H01; H01F; H01F27/00; H01F27/24; H01F27/25; H01H; H01H83/00; H01H83/14; H01H83/144; H02; H02H; H02H3/00; H02H3/26; H02H3/32; H02H3/33; H02H3/332
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
59 words
In a tape-wound magnetic transformer core, means for rounding the B-H hysteresis loop of the core and for inclining the loop in relation to the B axis, said means comprising the winding of the core with a plurality of interleaved layers of magnetizable material, the material of said interleaved layers all being of high permeability and of similar coercivity.
Claim 2
Dependent Claim
59 words
In a tape-wound magnetic transformer core, means for rounding the B-H hysteresis loop of the core and for inclining the loop in relation to the B axis, said means comprising the winding of the core with a plurality of interleaved layers of magnetizable material, the material of said interleaved layers all being of high permeability and of similar coercivity.
Claim 3
Dependent Claim
31 words
The core set forth in claim 1 wherein input terminals are provided at the first end of the primary winding, the terminals being adapted to receive sinusoidal or unipolar pulse excitation.
Claim 4
Dependent Claim
16 words
The core set forth in claim 1 wherein the resonant circuit forming means includes a capacitor.
Claim 5
Dependent Claim
18 words
The core of claim 1 in which said magnetizable material has a permeability of about 200,000 or more.
Claim 6
Dependent Claim
107 words
A ground fault circuit interruptor comprising: a transformer core having a plurality of coaxially wound interleaved strips of magnetically permeable material for producing a rounded hysteresis loop; a primary winding having at least one pair of wires passing through the core and connectable at a first end thereof to a voltage source and at an opposite end thereof to a load; a secondary winding wound on the core; and means connected in circuit with the secondary winding for interrupting current flow through a load in response to a preselected differential current flow through the wires resulting from fault current flowing from one of the wires to ground.
Claim 7
Dependent Claim
107 words
A ground fault circuit interruptor comprising: a transformer core having a plurality of coaxially wound interleaved strips of magnetically permeable material for producing a rounded hysteresis loop; a primary winding having at least one pair of wires passing through the core and connectable at a first end thereof to a voltage source and at an opposite end thereof to a load; a secondary winding wound on the core; and means connected in circuit with the secondary winding for interrupting current flow through a load in response to a preselected differential current flow through the wires resulting from fault current flowing from one of the wires to ground.
Claim 8
Dependent Claim
45 words
The interruptor set forth in claim 5 together with means connected in circuit with the secondary winding for forming a resonant circuit therewith in response to a preselected differential current flow and actuating the current interrupting means after a few cycles of the fault current.
Claim 9
Dependent Claim
17 words
The subject matter set forth in claim 6 wherein the resonant circuit forming means includes a capacitor.
Claim 10
Independent Claim
131 words
A method for interrupting a power circuit, in response to accidental contact, by an object with the circuit, thus causing a fault current, the method comprising the steps of: coaxially winding a plurality of interleaved layers of magnetically permeable material to form a core having a rounded hysteresis loop; positioning a primary winding through the core, the winding being connectable at a first end thereof to a voltage source and at an opposite end thereof to a load; positioning a secondary winding on the core; connecting an impedance across the secondary winding to form a resonant circuit therewith; and connecting the resonant circuit to an electromagnetic circuit breaker, the latter being connected in circuit with the primary winding, for interrupting the power circuit after a few cycles of the fault current.
Claim 11
Independent Claim
131 words
A method for interrupting a power circuit, in response to accidental contact, by an object with the circuit, thus causing a fault current, the method comprising the steps of: coaxially winding a plurality of interleaved layers of magnetically permeable material to form a core having a rounded hysteresis loop; positioning a primary winding through the core, the winding being connectable at a first end thereof to a voltage source and at an opposite end thereof to a load; positioning a secondary winding on the core; connecting an impedance across the secondary winding to form a resonant circuit therewith; and connecting the resonant circuit to an electromagnetic circuit breaker, the latter being connected in circuit with the primary winding, for interrupting the power circuit after a few cycles of the fault current.
Claim 12
Dependent Claim
106 words
Apparatus comprising in combination, a transformer core comprising a plurality of interleaved layers coaxially wound in a closed path, the layers being fabricated from magnetically permeable material of relatively low and similar coercivity, the core producing a rounded hysteresis loop, a primary winding comprising at least one pair of wires passing through the core and connectable at a first end thereof to a voltage source and at an opposite end thereof to a load, a secondary winding wound on the core, and means connected across the secondary winding for interrupting current flow through a load in response to a preselected differential current flow in the wires.
Claim 13
Dependent Claim
106 words
Apparatus comprising in combination, a transformer core comprising a plurality of interleaved layers coaxially wound in a closed path, the layers being fabricated from magnetically permeable material of relatively low and similar coercivity, the core producing a rounded hysteresis loop, a primary winding comprising at least one pair of wires passing through the core and connectable at a first end thereof to a voltage source and at an opposite end thereof to a load, a secondary winding wound on the core, and means connected across the secondary winding for interrupting current flow through a load in response to a preselected differential current flow in the wires.
Claim 14
Dependent Claim
128 words
Apparatus comprising in combination, a transformer core comprising a plurality of interleaved layers coaxially wound in a closed path, the layers being fabricated from magnetically permeable material of relatively low and similar coercivity, the core producing a rounded hysteresis loop, a primary winding comprising at least one pair of wires passing through the core and connectable at a first end thereof to a voltage source and at an opposite end thereof to a load, a secondary winding wound on the core, circuit breaking means connected in circuit with the wires, and means connected in circuit with the secondary winding for forming a resonant circuit therewith in response to a preselected differential current flow through the wires thus actuating the circuit breaking means after a few cycles of resonance.
Claim 15
Dependent Claim
128 words
Apparatus comprising in combination, a transformer core comprising a plurality of interleaved layers coaxially wound in a closed path, the layers being fabricated from magnetically permeable material of relatively low and similar coercivity, the core producing a rounded hysteresis loop, a primary winding comprising at least one pair of wires passing through the core and connectable at a first end thereof to a voltage source and at an opposite end thereof to a load, a secondary winding wound on the core, circuit breaking means connected in circuit with the wires, and means connected in circuit with the secondary winding for forming a resonant circuit therewith in response to a preselected differential current flow through the wires thus actuating the circuit breaking means after a few cycles of resonance.
References Cited (Backward Citations)
GB521125A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-12-27 | 1986-06-28 | 1986-12-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-12-27 | 1990-06-28 | 1990-12-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-12-27 | 1994-06-28 | 1994-12-28 | $7700.00 | Window Closed / Lapsed |