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US4716486A
Expired / Lapsed
US
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Electric motor comprising a thermistor-type overcurrent protection device
Assignee: SA ETRI A CORP OF FRANCE
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Filing: 1986-03-03
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Granted: 1987-12-29
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Expires: 2006-03-03
Abstract
Abstract A device providing protection against over-currents in the windings of an electric motor having a rotor (3) and at least two windings (1, 2) comprises at least two parallel thermistors (17, 18) each mounted in series with at least one motor winding (1, 2).
Inventors
- 👤 Janusz Sobiepanek
- 👤 Simon Aboukrat
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 04:43
CPC Classifications
H; H02; H02H; H02H7/00; H02H7/08; H02H7/0833; H02H7/085
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
119 words
An electronically switched direct-current motor comprising at least two motor windings (1, 2), and a device used in protection against overcurrent in the motor windings (1, 2) and in aid of motor restart after a stoppage of the motor, wherein said device comprises at least two positive temperature coefficient thermistors (17, 18), one (17) of said thermistors being series-connected with a first motor winding (1) whilst the other thermistor (18) is series-connected with a second winding (2), each thermistor being thermally independent from the other, wherein said first winding and said one of said thermistors, and said second winding and said other thermistor, when energized, have electrically parallel current paths between a source of direct current and the ground.
Claim 2
Dependent Claim
119 words
An electronically switched direct-current motor comprising at least two motor windings (1, 2), and a device used in protection against overcurrent in the motor windings (1, 2) and in aid of motor restart after a stoppage of the motor, wherein said device comprises at least two positive temperature coefficient thermistors (17, 18), one (17) of said thermistors being series-connected with a first motor winding (1) whilst the other thermistor (18) is series-connected with a second winding (2), each thermistor being thermally independent from the other, wherein said first winding and said one of said thermistors, and said second winding and said other thermistor, when energized, have electrically parallel current paths between a source of direct current and the ground.
Claim 3
Dependent Claim
49 words
A motor according to claim 1, wherein said motor comprises at least one shunt resistor (19), the ends of said resistor being connected respectively to one terminal of two adjacent motor windings at the point of connection of each motor winding (1, 2) to the associated thermistor (17, 18).
Claim 4
Dependent Claim
29 words
A motor according to claim 2, wherein the shunt resistor (19) has an ohmic value in the vicinity of the hot-state ohmic value of an adjacent thermistor (17, 18).
References Cited (Backward Citations)
US3673538A
Cited
DE2243949A1
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FR2212669A1
Cited
US3708720A
Cited
US3965392A
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GB2064899A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-12-28 | 1991-06-29 | 1991-12-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-12-28 | 1995-06-29 | 1995-12-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-12-28 | 1999-06-29 | 1999-12-29 | $7700.00 | Window Closed / Lapsed |