Patent US3757140A successfully refreshed from Google Patents.
US3757140A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Commutation circuits
Assignee: TECH/OPS SEVCON Inc A DE CORP
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Filing: 1971-05-20
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Granted: 1973-09-04
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Expires: 1991-05-20
Abstract
Abstract Commutation circuits for simultaneously commutating a plurality of main semi-conductor switching devices, each adapted to effect pulsed connection of an electrical supply to a load individual to the semi-conductor switching device, the simultaneous commutation of the switching devices facilitating variation of the mean power supplied to one relatively to the mean power supplied to another of the different loads.
Inventors
- 👤 D Gurwicz
- 👤 A Sloan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 16:37
CPC Classifications
H; H03; H03K; H03K17/00; H03K17/28; H03K17/292; H03K17/51; H03K17/56; H03K17/72; H03K17/722; H03K17/723
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
127 words
An electrical circuit for energizing a plurality of d.c. loads from a d.c. source, which circuit comprises: a plurality of main semi-conductor switching devices, one for each load, each connected with its load to effect repetitive connection of its load to the d.c. source and disconnection of its load therefrom; means for firing said main semi-conductor switching devices sUbstantially independently of one another so that the several loads can be connected with the d.c. source either simultaneously or at different times; a commutating capacitor; means for inductively charging said capacitor; and further semiconductor switching means whereby said commutating capacitor can be connected with all of the main semi-conductor switching devices when the latter are conducting and thereby reverse bias and commutate all of said main devices simultaneously.
Claim 2
Dependent Claim
127 words
An electrical circuit for energizing a plurality of d.c. loads from a d.c. source, which circuit comprises: a plurality of main semi-conductor switching devices, one for each load, each connected with its load to effect repetitive connection of its load to the d.c. source and disconnection of its load therefrom; means for firing said main semi-conductor switching devices sUbstantially independently of one another so that the several loads can be connected with the d.c. source either simultaneously or at different times; a commutating capacitor; means for inductively charging said capacitor; and further semiconductor switching means whereby said commutating capacitor can be connected with all of the main semi-conductor switching devices when the latter are conducting and thereby reverse bias and commutate all of said main devices simultaneously.
Claim 3
Dependent Claim
34 words
Circuit means as claimed in claim 1, further characterized by: means defining a discharge path of the commutating capacitor, operative during commutation of the main semi-conductor switching devices, which discharge path comprises the loads.
Claim 4
Dependent Claim
74 words
Circuit means as claimed in claim 1, wherein the loads are inductive and each load has a free wheel path which comprises a unidirectional conduction device and which affords maintenance of current flow through the load when its main semi-conductor switching device disconnects it from the d.c. source, and the discharge path of the commutating capacitor during commutation includes the loads and respective unidirectional conduction devices in the free wheel paths of the loads.
Claim 5
Dependent Claim
53 words
Circuit means as claimed in claim 1, further characterized by: a transformer having a primary winding connected in series between the d.c. source and the commutating capacitor to present a high impedance path during commutation and having a secondary winding connected with the commutating capacitor for the latter to be inductively charged therethrough.
Claim 6
Dependent Claim
101 words
Circuit means as claimed in claim 1, wherein said means for firing the main switching devices substantially independently of one another comprises: a master electrical oscillator for supplying output trains of electrical pulses; a plurality of pulse delay circuits, one for each main semi-conductor switching device, each connected with its switching device; and means for varying the delay of at least one of the pulse delay circuits so that the main switching devices can be switched on at different times and by reason of their simultaneous commutation can conduct current from the d.c. source to their respective loads for different periods.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-09-03 | 1977-03-05 | 1977-09-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-03 | 1981-03-05 | 1981-09-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-03 | 1985-03-05 | 1985-09-04 | $7700.00 | Window Closed / Lapsed |