US3728465A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrical apparatus with thermally stabilized cellulose insulation
Assignee: Hitachi Ltd
•
Filing: 1972-04-05
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Granted: 1973-04-17
•
Expires: 1992-04-05
Abstract
Abstract An electrical apparatus containing an insulating oil which is in contact with a cellulosic insulating material improved in heat resistance and stability by incorporation of a urethane compound containing at least one urethane bond and having a molecular weight of 75 to 1000.
Inventors
- 👤 E Yasui
- 👤 A Miyoshi
- 👤 N Shito
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 14:00
CPC Classifications
H; H02; H02K; H02K3/00; H02K3/30; H01; H01B; H01B3/00; H01B3/18; H01B3/185; H01F; H01F27/00; H01F27/28; H01F27/32; H01F27/324
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
28 words
An electrical apparatus according to claim 1, wherein said amount of said urethane compound is from 0.3 to 2 percent by weight, based on the amount of nitrogen.
Claim 2
Dependent Claim
50 words
N-substituted urethane compounds having the formula wherein R2 and R3 are each an aliphatic hydrocarbon group, a substituted aromatic hydrocarbon group, chlorine, hydrogen or nitro and R4 is an aliphatic hydrocarbon group, a substituted aliphatic hydrocarbon group, an aromatic hydrocarbon group, a substituted aromatic hydrocarbon group, chlorine or nitro; and
Claim 3
Dependent Claim
20 words
An electrical apparatus according to claim 1, wherein said urethane compound has a molecular weight of from 100 to 300.
Claim 4
Dependent Claim
12 words
polyurethane compounds having at least two urethane bonds in the molecule thereof.
Claim 5
Dependent Claim
18 words
An electrical apparatus according to claim 1, wherein said urethane compound is selected from the group consisting of
Claim 6
Dependent Claim
34 words
An electrical apparatus according to claim 1, wherein said cellulosic insulating material comprises at least one member selected from the group consisting of kraft paper, Manila paper, craped paper, cotton cloth, wood and press-boaRd.
Claim 7
Dependent Claim
34 words
An electrical apparatus according to claim 4, wherein said urethane compound comprises at least one member selected from the group consisting of NH2COOCH3, NH2COOCH2CH3, NH2COOCH2CH2CH3, NH2COCH(CH3)2, NH2COOCH2CH2CH2CH3, NH2COOCH2CH CH2, NH2COOC6H5, NH2COOC6H4CH3, NH2COOC6H3(CH3)2, and NH2COOC6H4NO2.
Claim 8
Dependent Claim
37 words
An electrical apparatus according to claim 4, wherein said urethane compound comprises at least one member selected from the group consisting of HCONHCOOC2H5, C3H7CONHCOOCH3, (CH3)2NCOOC2H5, C2H5NHCOOC2H5, C6H5NHCOOC6H4CH3, NO2HCOO(C2H5)2, CH2ClNHCOOC2H5, Br2NHCOOC2H5, CH3OCONHCOOCH3, C2H5OCONHCOOC2H5, C3H7OCONHCOOC3H7, CH3OCONHCOOC2H5, CH3CONHCOOCH3 and CH3NHCOOC2H5.
Claim 9
Dependent Claim
28 words
An electrical apparatus according to claim 4, wherein said urethane compound comprises at least one member selected from the group consisting of C6H5OCONH(CH2)4NHCOOC6H5, CH3OCONHC10H6NHCOOCH3, H2NCOO(CH2)2OCONH2, CH3NHCOO(CH2)2OCO(NHCH3)3, C2H5OCONHCH2NHCOOC2H5 and
References Cited (Backward Citations)
US3224902A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-04-16 | 1976-10-16 | 1977-04-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-16 | 1980-10-16 | 1981-04-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-16 | 1984-10-16 | 1985-04-17 | $7700.00 | Window Closed / Lapsed |