US3562587A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Overheating control device for alternating current motor
Assignee: Danfoss AS
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Filing: 1968-09-19
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Granted: 1971-02-09
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Expires: 1988-09-19
Abstract
Abstract The invention relates to an overheating control device for an alternating current motor. The device comprises a symmetrical controlled semiconductor valve in the motor lead and PTC resistor means thermally coupled to the motor windings. The PTC resistor means is connected to the control electrode of the semiconductor valve and concomitant with a temperature rise in the motor windings, the current flowing through the PTC resistor means decreases to effect a closing of the semiconductor valve.
Inventors
- 👤 Sven Forst
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 13:02
CPC Classifications
H; H02; H02H; H02H7/00; H02H7/08; H02H7/085; H02H7/0852; H02K; H02K11/00; H02K11/20; H02K11/25
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
97 words
A motor protection circuit for interrupting the supply of power to an alternating current motor upon an abnormal increase in the temperature of the windings of said motor, comprising, a pair of supply lines for connecting said motor to a power source, a symmetrical controlled semiconductor valve in one of said supply lines, said valve having a control electrode, a control line extending between said control electrode and said one of said supply lines at a point between said power source and said valve, a PTC-resistor in said control line and being thermally coupled to said windings.
Claim 2
Dependent Claim
97 words
A motor protection circuit for interrupting the supply of power to an alternating current motor upon an abnormal increase in the temperature of the windings of said motor, comprising, a pair of supply lines for connecting said motor to a power source, a symmetrical controlled semiconductor valve in one of said supply lines, said valve having a control electrode, a control line extending between said control electrode and said one of said supply lines at a point between said power source and said valve, a PTC-resistor in said control line and being thermally coupled to said windings.
Claim 3
Dependent Claim
34 words
A circuit according to claim 1 including a second PTC-resistor in said control line in series with said first referred to resistor, said second PTC-resistor being thermally coupled to a portion of said windings.
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) | 1974-02-08 | 1974-08-10 | 1975-02-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-02-08 | 1978-08-10 | 1979-02-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-02-08 | 1982-08-10 | 1983-02-09 | $7700.00 | Window Closed / Lapsed |