US4066937A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Control circuit for a two speed single phase motor
Assignee: Lennox Industries Inc
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Filing: 1976-01-13
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Granted: 1978-01-03
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Expires: 1996-01-13
Abstract
Abstract A control circuit for a two-speed single-phase motor as used in a hermetic refrigerant compressor which includes means for preventing welding of the start relay contacts of the start relay means by electrical discharge from the run capacitor. In one aspect of the invention, a discharge path is provided for the run capacitor by switches and auxiliary contactor means. In another and preferred aspect of the invention, a negative temperature coefficient thermistor is used in series with and between the start capacitor means and the start relay contacts for limiting the current to the start windings from a source of power and for limiting the current discharged into the start capacitor means from the run capacitor after the motor is deenergized.
Inventors
- 👤 David M. Pfarrer
- 👤 Leonard J. Van Essen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 07:55
CPC Classifications
H; H02; H02P; H02P1/00; H02P1/16; H02P1/42; H02P1/44; H02P1/445
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
119 words
For use with a single-phase two-speed motor comprising a main winding, a start winding means including a low speed start winding and a high speed start winding in circuit with the main winding and adapted to provide either a high speed operation or low speed operation, low-speed contactor means, high speed contactor means, start relay means, start capacitor means and run capacitor means, a thermistor in series with the start contacts of the start relay means for preventing welding of the start contacts of the start relay means, the start capacitor means being in parallel with the run capacitor means and the thermistor and start contacts are electrically disposed between the start capacitor means and the run capacitor means.
Claim 2
Dependent Claim
119 words
For use with a single-phase two-speed motor comprising a main winding, a start winding means including a low speed start winding and a high speed start winding in circuit with the main winding and adapted to provide either a high speed operation or low speed operation, low-speed contactor means, high speed contactor means, start relay means, start capacitor means and run capacitor means, a thermistor in series with the start contacts of the start relay means for preventing welding of the start contacts of the start relay means, the start capacitor means being in parallel with the run capacitor means and the thermistor and start contacts are electrically disposed between the start capacitor means and the run capacitor means.
Claim 3
Dependent Claim
15 words
A control circuit as in claim 1 wherein the thermistor is a negative coefficient thermistor.
Claim 4
Dependent Claim
27 words
A control circuit as in claim 2 including means for providing a discharge path for the run capacitor means during the off cycle of the two-speed motor.
Claim 5
Dependent Claim
22 words
A control circuit as in claim 2 including means for limiting the current to the start windings from a source of power.
Claim 6
Dependent Claim
71 words
A control circuit as in claim 1, wherein said low speed contactor means including normally open contacts for connecting said low speed start winding in circuit with a source of power upon energization of the low speed contactor means, and said high speed contactor means including normally open contacts for connecting said high speed start winding in circuit with the source of power upon energization of the high speed contactor means.
Claim 7
Dependent Claim
81 words
A control circuit as in claim 5 wherein the start capacitor means includes a first capacitor and a second capacitor, said high speed contactor means including a normally open contact in series with the first capacitor, whereby during low speed motor operation, the second start capacitor is in the circuit to the low speed start winding and during high speed motor operation, the contact in series with the first capacitor is also in the circuit to the high speed start winding.
Claim 8
Dependent Claim
49 words
A control circuit as in claim 1 wherein said negative temperature coefficient thermistor limits the current to the start windings from a source of power and limits the current discharged into the start capacitor means from the run capacitor means when the two speed motor is deenergized after use.
References Cited (Backward Citations)
US2167018A
Cited
US2280971A
Cited
US2476073A
Cited
US2752548A
Cited
GB1178661A
Cited
US3559016A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-01-02 | 1981-07-04 | 1982-01-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-01-02 | 1985-07-04 | 1986-01-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-01-02 | 1989-07-04 | 1990-01-03 | $7700.00 | Window Closed / Lapsed |