US3707661A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrical drive motor protective means
Assignee: CMD ELECTRONICS Inc
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Filing: 1971-03-22
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Granted: 1972-12-26
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Expires: 1991-03-22
Abstract
Abstract An electrical drive motor for the compressor of a vapor compression cycle refrigeration system is protected against failure otherwise possibly occurring due to excessively frequent starting by the combination therewith of a two terminal electrical network which delays energization of the electrical drive motor for a predetermined interval of time.
Inventors
- 👤 Ray J King
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 20:24
CPC Classifications
H; H02; H02H; H02H7/00; H02H7/08; H02H7/0816
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
162 words
In a vapor compression cycle refrigeration system having a compressor, an electrical drive motor for the compressor, an electrical starter for energizing the drive motor and including an operating winding, and control means electrically connected to the operating winding and operative between electrically conductive and nonconductive states for electrically energizing the operating winding and thereby energizing the drive motor, the combination therewith of means for protecting the drive motor against failure otherwise possibly occurring due to excessively frequent starting and comprising a two terminal electrical network means electrically connected with the operating winding of the electrical starter for delaying flow of current therethrough for a predetermined interval of time following a winding energizing change in the conductive state of said control means, said two terminal electrical network means initially being effectively nonconductive at application of an electrical potential across the two terminals thereof and becoming effectively conductive following expiration of said predetermined interval of time after such application of an electrical potential.
Claim 2
Dependent Claim
162 words
In a vapor compression cycle refrigeration system having a compressor, an electrical drive motor for the compressor, an electrical starter for energizing the drive motor and including an operating winding, and control means electrically connected to the operating winding and operative between electrically conductive and nonconductive states for electrically energizing the operating winding and thereby energizing the drive motor, the combination therewith of means for protecting the drive motor against failure otherwise possibly occurring due to excessively frequent starting and comprising a two terminal electrical network means electrically connected with the operating winding of the electrical starter for delaying flow of current therethrough for a predetermined interval of time following a winding energizing change in the conductive state of said control means, said two terminal electrical network means initially being effectively nonconductive at application of an electrical potential across the two terminals thereof and becoming effectively conductive following expiration of said predetermined interval of time after such application of an electrical potential.
Claim 3
Dependent Claim
107 words
The combination according to claim 1 wherein said two terminal electrical network means is electrically connected in series with the operating winding and further wherein said two terminal electrical network means comprises a switch device operative between conductive and nonconductive states for controlling conduction through said two terminal electrical network means and timing means electrically connected to said switch device and to said two terminals of said two terminal electrical network for sensing the presence of an electrical potential across said two terminals, for timing said predetermined interval and for effecting a change of said switch device to said conductive state oN expiration of said predetermined interval.
Claim 4
Dependent Claim
16 words
The combination according to claim 2 wherein said switch device comprises a gate controlled semiconductor switch.
Claim 5
Dependent Claim
116 words
The combination according to claim 1 wherein said two terminal electrical network means comprises a thyristor operative between conductive and nonconductive states for controlling conduction through said two terminal electrical network means, timing circuit means electrically connected to the two terminals of said two terminal electrical network means for sensing the presence of an electrical potential thereacross and for timing said predetermined interval and electrically connected to said thyristor for effecting a change thereof to said conductive state on expiration of said predetermined interval, and conduction maintaining circuit means electrically connected to said thyristor for sensing conduction therethrough of an electrical current and for continuing said thyristor in said conductive state during continuance of such conduction.
Claim 6
Dependent Claim
58 words
The combination according to claim 4 wherein said thyristor is a controlled rectifier and further wherein said two terminal electrical network means comprises a rectifier bridge electrically connected with said controlled rectifier, said timing circuit means and said conduction maintaining circuit means for accommodating insertion of said two terminal electrical network means into an alternating current electrical circuit.
Claim 7
Dependent Claim
113 words
The combination according to claim 4 wherein said thyristor comprises first and second terminals and a control gate whereby said thyristor becomes conductive upon said control gate being electrically positive relative to a particular one of said first and second terminals thereof and further wherein said timing circuit means comprises a resistance and capacitance network for accumulating electrical energy at a predetermined rate and a discharge triggering device for controlling the discharge of accumulated electrical energy, said timing circuit means being electrically connected with said one thyristor terminal for applying a negative going pulse thereto so that said control gate becomes electrically positive with respect thereto and conduction through said thyristor is initiated.
Claim 8
Dependent Claim
90 words
The combination according to claim 4 wherein said thyristor comprises first and second terminals and a control gate whereby said thyristor becomes conductive upon said control gate being electrically positive relative to a particular one of said first and second terminals thereof and further wherein said conduction maintaining circuit means comprises a resistance and capacitance network electrically connected between said control gate and said one thyristor terminal for accumulating electrical energy during conduction through said thyristor and for maintaining said control gate electrically positive through intermittent fluctuations of such conduction.
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) | 1975-12-26 | 1976-06-26 | 1976-12-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-12-26 | 1980-06-26 | 1980-12-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-12-26 | 1984-06-26 | 1984-12-26 | $7700.00 | Window Closed / Lapsed |