Patent US4222001A successfully refreshed from Google Patents.
US4222001A
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US
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Self-excited dynamo-electric machines with improved start-up characteristics
Assignee: Robert Bosch GmbH
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Filing: 1979-01-26
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Granted: 1980-09-09
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Expires: 1999-01-26
Abstract
Abstract In known generators and motors a regulator circuit connected in series with the exciter winding creates too much resistance to allow self-excitation to start at very low speeds. The regulator circuit is therefore shunted by a positive temperature coefficient resistor. This has very low resistance at low temperatures causing sufficient current flow through the exciter winding even at low speeds.
Inventors
- 👤 Wolfgang Kofink
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 18:51
CPC Classifications
H; H02; H02P; H02P9/00; H02P9/08; H02J; H02J7/00; H02J7/14; H02J7/16; H02J7/163
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
75 words
In a self-excited generator having an exciter winding and regulator circuit means connected in series with said exciter winding for regulating the flow of current therethrough, apparatus for improving the self-excitation of said generator, said apparatus comprising positive temperature coefficient resistor means (10) having a resistance increasing substantially with increasing temperatures connected in parallel with said regulator circuit means, whereby said current flowing through said exciter winding at start-up of said generator is substantially increased.
Claim 2
Dependent Claim
75 words
In a self-excited generator having an exciter winding and regulator circuit means connected in series with said exciter winding for regulating the flow of current therethrough, apparatus for improving the self-excitation of said generator, said apparatus comprising positive temperature coefficient resistor means (10) having a resistance increasing substantially with increasing temperatures connected in parallel with said regulator circuit means, whereby said current flowing through said exciter winding at start-up of said generator is substantially increased.
Claim 3
Dependent Claim
36 words
A generator as set forth in claim 1, wherein said resistance of said positive temperature coefficient resistor increases by a factor of approximately 20 due to self-heating with a thermal time constant of approximately one second.
Claim 4
Dependent Claim
36 words
A generator as set forth in claim 1, wherein said regulator circuit means has a predetermined resistance; and wherein said resistance of said positive temperature coefficient resistor at said start-up is less than said predetermined resistance.
Claim 5
Dependent Claim
20 words
A generator as set forth in claim 1, wherein said regulator circuit means comprise the emitter-collector circuit of a transistor.
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) | 1983-09-09 | 1984-03-10 | 1984-09-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-09-09 | 1988-03-10 | 1988-09-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-09-09 | 1992-03-10 | 1992-09-09 | $7700.00 | Window Closed / Lapsed |