Patent US4604673A successfully refreshed from Google Patents.
US4604673A
Expired / Lapsed
US
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Distribution transformer with surge protection device
Assignee: General Electric Co
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Filing: 1984-11-20
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Granted: 1986-08-05
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Expires: 2004-11-20
Abstract
Abstract This distribution transformer is of the shell type and includes within its oil-filled tank a layer-type high voltage winding and a layer-type low voltage winding. The low voltage winding is divided into two sections with a grounded interconnection between said two sections. A metal oxide varistor device is mounted within the oil-filled tank and is connected between the high voltage terminal of the high voltage winding and ground. There is another connection between the mid-point of the varistor device and the mid-point of the high voltage winding. The varistor device so connected protects the high voltage winding against both voltage surges entering via its terminals and current surges entering via the terminals of the low voltage winding.
Inventors
- 👤 Charles W. Schoendube
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 20:11
CPC Classifications
H; H01; H01F; H01F27/00; H01F27/40; H01F27/402; H01F27/34; H01F27/343; H01F27/404; H02; H02H; H02H7/00; H02H7/04
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
236 words
A distribution-type single-phase transformer having a surge protection arrangement comprising; (a) a layer-type high voltage winding having two terminals, one being a high voltage terminal for connection to a high voltage line, (b) a divided low voltage winding comprising two winding sections and a grounded interconnection between said winding sections, (c) varistor means having opposite ends and comprising a plurality of stacked metal oxide varistor elements between said ends, said varistor means being connected from said high voltage terminal of said high voltage winding to ground, (d) means for connecting said varistor means at not more than two points intermediate its ends to a corresponding number of points on said high voltage winding intermediate the terminals of said high voltage winding, (e) the portions of said varistor means located between each of its opposite ends and an adjacent intermediate connection and any portion located between adjacent intermediate connections, if more than one intermediate connection is present, being substantially equal in impulse protective level rating, (f) the corresponding portions of said high voltage winding being substantially equal in numbers of turns, whereby protection is provided for said high voltage winding against both voltage surges entering said transformer via the terminals of said high voltage winding and current surges entering said transformer via the terminals of said low voltage winding, (g) said transformer further comprising an oil-filled tank in which said windings and said varistor means are located.
Claim 2
Dependent Claim
236 words
A distribution-type single-phase transformer having a surge protection arrangement comprising; (a) a layer-type high voltage winding having two terminals, one being a high voltage terminal for connection to a high voltage line, (b) a divided low voltage winding comprising two winding sections and a grounded interconnection between said winding sections, (c) varistor means having opposite ends and comprising a plurality of stacked metal oxide varistor elements between said ends, said varistor means being connected from said high voltage terminal of said high voltage winding to ground, (d) means for connecting said varistor means at not more than two points intermediate its ends to a corresponding number of points on said high voltage winding intermediate the terminals of said high voltage winding, (e) the portions of said varistor means located between each of its opposite ends and an adjacent intermediate connection and any portion located between adjacent intermediate connections, if more than one intermediate connection is present, being substantially equal in impulse protective level rating, (f) the corresponding portions of said high voltage winding being substantially equal in numbers of turns, whereby protection is provided for said high voltage winding against both voltage surges entering said transformer via the terminals of said high voltage winding and current surges entering said transformer via the terminals of said low voltage winding, (g) said transformer further comprising an oil-filled tank in which said windings and said varistor means are located.
Claim 3
Dependent Claim
72 words
A transformer as defined in claim 1, said transformer being a shell-type transformer wherein said low voltage winding comprises an inner coil constituting one section of the low voltage winding and an outer coil of substantially equal number of turns constituting the other section of the low voltage winding, with a common grounded interconnection between said coils, said high voltage winding being arranged between said inner and outer low voltage winding coils.
Claim 4
Dependent Claim
15 words
A transformer as defined in claim 2, wherein said low voltage winding coils are non-interlaced.
Claim 5
Dependent Claim
38 words
A transformer as defined in claim 3, said varistor means being connected substantially at its mid-point, in terms of impulse protective level rating, to substantially the mid-point of said high voltage winding, in terms of turns of winding.
Claim 6
Dependent Claim
59 words
A transformer as defined in claim 3, said varistor means comprising an even number of stacked varistor elements of substantially the same impulse protective level rating and having an equal number of said elements on opposite sides of a mid-point, said mid-point being connected to substantially the mid-point of said high voltage winding, in terms of turns of winding.
Claim 7
Dependent Claim
44 words
A transformer as defined in claim 3, said varistor means being connected substantially at its 1/3 and 2/3 points, in terms of impulse protective level rating, to substantially the 1/3 and 2/3 points on said high voltage winding, in terms of turns of winding.
Claim 8
Dependent Claim
39 words
A transformer as defined in claim 3, said varistor means comprising a multiple of three stacked varistor elements and being connected substantially at points respectively 1/3 and 2/3 of its length to corresponding points on said high voltage winding.
Claim 9
Dependent Claim
14 words
A transformer as defined in claim 3, said varistor elements comprising zinc oxide varistors.
Claim 10
Dependent Claim
36 words
A transformer as defined in claim 1 in which said tank contains a dielectric oil and in which said windings and said varistor means are located within said tank and are immersed in said dielectric oil.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-08-04 | 1990-02-03 | 1990-08-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-08-04 | 1994-02-03 | 1994-08-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-08-04 | 1998-02-03 | 1998-08-05 | $7700.00 | Window Closed / Lapsed |