Patent US3753188A successfully refreshed from Google Patents.
US3753188A
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Inductive electric apparatus
Assignee: Hitachi Ltd
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Filing: 1970-12-28
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Granted: 1973-08-14
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Expires: 1990-12-28
Abstract
Abstract An inductive electric apparatus which comprises a polycylic hydrocarbon oil mixture having a flash point of more than 150*C and consisting of polycyclic naphtenic hydrocarbons having two to five rings and polycyclic aromatic hydrocarbons having two to four rings, each side chain alkyl group attached to said rings having not more than four carbon atoms, an electroconductive coil and a cellulose insulator in combination. The inductive electric apparatus can have a larger increase in allowable temperature than that of a combination of the ordinary hydrocarbon insulating oil and the cellulose insulator, and accordingly it is possible to make the apparatus smaller and lighter.
Inventors
- 👤 A Miyoshi
- 👤 K Okuda
- 👤 T Nagaoka
- 👤 H Takahashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 09:02
CPC Classifications
H; H01; H01F; H01F27/00; H01F27/08; H01F27/10; H01F27/12; H01F27/125; H01B; H01B3/00; H01B3/18; H01B3/20; H01B3/22; H01B3/48; H01B3/485
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
20 words
An inductive electric apparatus according to claim 1, wherein said cellulosic material is selected from kraft paper and cyanoethylated paper.
Claim 2
Dependent Claim
106 words
An inductive electric apparatus according to claim 1, wherein said component A of the polycyclic naphthenic hydrocarbons comprisEs a mixture of a plurality of polycyclic hydrocarbons having two to five rings, or a mixture of a plurality of lower alkyl derivatives thereof, or a mixture of the polycyclic hydrocarbons and the lower alkyl derivatives thereof and has a specific gravity (d415) of 0.85 - 0.99, refractive index (nD20) of 1.45 - 1.60, a viscosity (30*C) of 10 - 40 CST, an atomic ratio of hydrogen to carbon of 1.75 - 2.00, a flash point of 125*C or higher and a pour point of -30* to -60*C.
Claim 3
Dependent Claim
97 words
An inductive electric apparatus according to claim 1, wherein said component B of the polycyclic aromatic hydrocarbons comprises a mixture of a plurality of polycyclic aromatic hydrocarbons having two to four rings, a mixture of a plurality of lower alkyl derivatives thereof, or a mixture of the polycyclic aromatic hydrocarbons and the lower alkyl derivatives thereof, and has a specific gravity (d415) of 1.00 - 1.20, a refractive index (nD20) of 1.50 - 1.68, a viscosity (50*C) of 10 - 25 CST, a flash point of 150*C or higher and a pour point of -40*C or less.
Claim 4
Dependent Claim
54 words
An inductive electric apparatus according to claim 1, wherein said insulating oil is an oil of polycyclic hydrocarbon mixture consisting of component (A) comprising polycyclic napthenic hydrocarbons having three to five rings and component (B) comprising polycyclic aromatic hydrocarbons having two to three rings at a mixing ratio of A/B of 70/30 by volume.
Claim 5
Dependent Claim
54 words
An inductive electric apparatus according to claim 1, wherein said insulating oil is an oil of polycyclic hydrocarbon mixture consisting of component (A) comprising polycyclic naphthenic hydrocarbons having four to five rings and component (B) comprising polycyclic aromatic hydrocarbons having three to four rings at a mixing ratio of (A)/(B) of 70/30 by volume.
Claim 6
Dependent Claim
54 words
An inductive electric apparatus according to claim 1, wherein said insulating oil is an oil of polycyclic hydrocarbon mixture consisting of component (A) comprising polycyclic naphthenic hydrocarbons having three to four rings and component (B) comprising polycyclic aromatic hydrocarbons having two to three rings at a mixing ratio of (A)/(B) of 50/50 by volume.
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) | 1976-08-13 | 1977-02-12 | 1977-08-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-13 | 1981-02-12 | 1981-08-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-13 | 1985-02-12 | 1985-08-14 | $7700.00 | Window Closed / Lapsed |