US3619722A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Refrigeration protective system
Assignee: Acme Industries Inc
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Filing: 1970-05-04
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Granted: 1971-11-09
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Expires: 1990-05-04
Abstract
Abstract A protective control system for a refrigeration circuit incorporating a current-sensitive, manually resettable switch employed in conjunction with a time delay switch and a resistor wherein the current-sensitive switch is adapted to be selectively connected to the resistor, and tripped open thereby, in the event a malfunction occurs in the compressor motor starter means, or an abnormal condition exists at the compressor motor, as sensed by a protective motor switch. The use of the time delay switch prevents short cycling of the refrigeration circuit and upon the current-sensitive switch being connected in series across the load for a predetermined time interval with the resistor, the current-sensitive switch will open to protect the circuit, requiring manually resetting, and provide an opportunity for inspection of the apparatus prior to restarting of the compressor motor.
Inventors
- 👤 Melvin C Gill
- 👤 William M Dartt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 02:04
CPC Classifications
H; H02; H02H; H02H7/00; H02H7/08; H02H7/0816
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
264 words
A refrigeration protective system for electrical refrigeration control circuits supplied from a power supply including first and second conductors utilizing compressor motor starter means, a compressor motor protective switch movable between open and closed positions and thermally operated switch means selectively connected in series with said starter means across said power supply conductors for selectively energizing the motor starter means upon the demand for cooling, the improvement comprising, in combination, a manually resettable, current-sensitive switch connected in series with said thermally operated switch to said first power supply conductor, a first resistor having first and second terminals, said second terminal being connected to said second power supply conductor, time delay switch means connected in series with said thermally operated switch and said current-sensitive switch having a first position connecting said thermally operated and current-sensitive switches with said starter means and a normal second position connecting said thermally operated and current-sensitive switches to said first terminal of said resistor to place said resistor in series with said current-sensitive switch across said power supply conductors, and control switch means interposed between said time delay switch second position and said resistor first terminal controlled by said protective switch whereby upon closing of said thermally operated switch in demand for cooling said currentsensitive switch is connected to said resistor and will trip open if said protective switch is open to indicate an abnormal condition at said compressor motor, said control switch means disconnecting said resistor from said time delay switch and current-sensitive switch upon said protective switch being closed to indicate a normal condition of the compressor motor.
Claim 2
Dependent Claim
264 words
A refrigeration protective system for electrical refrigeration control circuits supplied from a power supply including first and second conductors utilizing compressor motor starter means, a compressor motor protective switch movable between open and closed positions and thermally operated switch means selectively connected in series with said starter means across said power supply conductors for selectively energizing the motor starter means upon the demand for cooling, the improvement comprising, in combination, a manually resettable, current-sensitive switch connected in series with said thermally operated switch to said first power supply conductor, a first resistor having first and second terminals, said second terminal being connected to said second power supply conductor, time delay switch means connected in series with said thermally operated switch and said current-sensitive switch having a first position connecting said thermally operated and current-sensitive switches with said starter means and a normal second position connecting said thermally operated and current-sensitive switches to said first terminal of said resistor to place said resistor in series with said current-sensitive switch across said power supply conductors, and control switch means interposed between said time delay switch second position and said resistor first terminal controlled by said protective switch whereby upon closing of said thermally operated switch in demand for cooling said currentsensitive switch is connected to said resistor and will trip open if said protective switch is open to indicate an abnormal condition at said compressor motor, said control switch means disconnecting said resistor from said time delay switch and current-sensitive switch upon said protective switch being closed to indicate a normal condition of the compressor motor.
Claim 3
Dependent Claim
31 words
In a refrigeration protective system as in claim 1 wherein said control switch means includes normally open contacts interposed between said time delay switch first position and said motor starter means.
Claim 4
Dependent Claim
33 words
In a refrigeration protective system as in claim 2 wherein said control switch means includes normally open holding switch contacts interposed between said thermally operated and current-sensitive switches and said control switch means.
Claim 5
Dependent Claim
90 words
In a refrigeration protective system as in claim 1 wherein said motor starting means includes auxiliary normally closed contacts which open upon complete energization of said motor starting means, a second resistor having a second terminal connected to said second supply conductor and a first terminal, said normally closed auxiliary contacts being interposed between said second resistor first terminal and said motor starter means whereby malfunctioning of said starter means closes said auxiliary contacts connecting said second resistor in series with said current-sensitive switch to trip open said current-sensitive switch.
Claim 6
Dependent Claim
30 words
In a refrigeration protective system as in claim 4 wherein said first resistor comprises a central tap resistor and said second resistor comprises a portion of said central tap resistor.
Claim 7
Dependent Claim
115 words
A refrigeration protective system for electrical refrigeration circuits comprising, in combination, compressor motor starter means having auxiliary normally closed contacts, a thermally operated switch sensing the temperature of the medium being cooled, a manually resettable current-sensitive switch connected in series with said thermally operated switch, power supply means, said switches selectively connecting said motor starter means to said power supply means, a resistor connected in parallel with said motor starter means in series with said auxiliary contacts, said auxiliary contacts being interposed in the circuit between said resistor and said motor starter means whereby closing of said auxiliary contacts upon said switches being closed overloads and opens said current-sensitive switch after a predetermined time interval.
Claim 8
Dependent Claim
115 words
A refrigeration protective system for electrical refrigeration circuits comprising, in combination, compressor motor starter means having auxiliary normally closed contacts, a thermally operated switch sensing the temperature of the medium being cooled, a manually resettable current-sensitive switch connected in series with said thermally operated switch, power supply means, said switches selectively connecting said motor starter means to said power supply means, a resistor connected in parallel with said motor starter means in series with said auxiliary contacts, said auxiliary contacts being interposed in the circuit between said resistor and said motor starter means whereby closing of said auxiliary contacts upon said switches being closed overloads and opens said current-sensitive switch after a predetermined time interval.
Claim 9
Dependent Claim
169 words
In a refrigeration protective system as in claim 6, a compressor motor protective switch movable between open and closed positions indicating normal and malfunctioning conditions of a compressor motor, respectively, a control relay connected in series with said protective switch, a time delay switch connected in series with said thermally operated and current-sensitive switches having a normal position opening the circuit between said switches and said motor starting means and connecting said protective switch and control relay in series with said switches and a timed delay closed position establishing the circuit to said motor starting means, a conductor connecting said resistor to said time delay switch normal position, said control relay including first normally closed contacts interposed in said conductor which open upon energization of said relay, second normally open contacts bypassing said time delay switch and connecting said protective switch to said thermally operated and current-sensitive switches to hold said relay energized and third normally open contacts interposed between said time delay switch and said motor starter means.
Claim 10
Dependent Claim
54 words
In a refrigeration protective system as in claim 7 wherein said resistor includes a central tap terminal, said auxiliary contacts being connected to said central tap terminal whereby the resistance value of said resistor through said auxiliary contacts differs with respect to the resistance value of current passing through said control relay first contacts.
Claim 11
Dependent Claim
115 words
A refrigeration protective system for electrical refrigeration circuits comprising, in combination, compressor motor starting means, a thermally operated switch and a current-sensitive switch connected in series, a resistor, a time delay switch alternately connecting said switches in series with said motor starting means or said resistor across a power supply, said time delay switch having a normal position connecting said switches to said resistor, a compressor motor protective switch having a normally closed position controlling a control relay, said control relay including contact means disconnecting said switches and said resistor in the normal position of said time delay switch upon said protective switch being in the normally closed position and upon said switches being closed.
Claim 12
Dependent Claim
115 words
A refrigeration protective system for electrical refrigeration circuits comprising, in combination, compressor motor starting means, a thermally operated switch and a current-sensitive switch connected in series, a resistor, a time delay switch alternately connecting said switches in series with said motor starting means or said resistor across a power supply, said time delay switch having a normal position connecting said switches to said resistor, a compressor motor protective switch having a normally closed position controlling a control relay, said control relay including contact means disconnecting said switches and said resistor in the normal position of said time delay switch upon said protective switch being in the normally closed position and upon said switches being closed.
Claim 13
Dependent Claim
53 words
In a refrigeration protective system as in claim 9, said motor starting means including normally closed auxiliary contacts, and resistance means connected in parallel with said motor starter means through said auxiliary contacts imposing an overload upon and opening said current-sensing switch upon closing of said auxiliary contacts when said starter means malfunctions.
Claim 14
Dependent Claim
26 words
In a refrigeration protective system as in claim 10 wherein said resistor includes a central tap and said resistance means comprises a portion of said resistor.
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) | 1974-11-08 | 1975-05-10 | 1975-11-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-08 | 1979-05-10 | 1979-11-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-08 | 1983-05-10 | 1983-11-09 | $7700.00 | Window Closed / Lapsed |