US3560796A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Relay control system for prevention of contact erosion
Assignee: Honeywell Inc
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Filing: 1969-12-11
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Granted: 1971-02-02
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Expires: 1989-12-11
Abstract
Abstract A control system for energizing an electrical relay and electrical load from a source of alternating current so that any relay contact bounce occurs during a portion of the applied alternating current source in a fashion to eliminate contact erosion. The control of the relay is accomplished by a synchronous switching means that is responsive to a voltage ripple superimposed on a direct current voltage from a bridge. The bridge contains an impedance which unbalances the voltage ripple in such a manner as to provide for a predictable mode of synchronous switching. The relay contacts are selected of dissimilar materials and operate with the predictable mode of synchronous switching so that there is little or no erosion of the contacts themselves.
Inventors
- 👤 William R Landis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 17:57
CPC Classifications
H; H01; H01H; H01H9/00; H01H9/54; H01H9/56; H03; H03K; H03K17/00; H03K17/28; H03K17/51; H03K17/56; H03K17/72; H03K3/00; H03K3/02; H03K3/35; H03K3/351
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
213 words
A relay control system for energizing electrical load means during a predetermined phase of an alternating current voltage source to prevent erosion of relay contact means during the closure and subsequent bounce of the contact means, by the contact means being of dissimilar materials that resist erosion by the load current arc that is drawn at said predetermined phase of the alternating current voltage source, including: rectifier means adapted to be connected to said alternating current voltage source and having a direCt current output voltage with a superimposed ripple voltage; said rectifier means including means to unbalance said ripple voltage; relay switching means including relay means energized by said output voltage and synchronously switched by a voltage swing of said unbalanced ripple voltage; and said relay means having contact means of dissimilar materials to inhibit contact erosion upon said contact means bouncing during said predetermined phase of said alternating current voltage source; said load means adapted to be energized from said source by the operation of said relay contact means, with said contact means being synchronously operated with said alternating current voltage source by said unbalanced ripple voltage so that said relay contact means bounce during said phase of said source when said contact means resist erosion caused by any load current arc.
Claim 2
Dependent Claim
213 words
A relay control system for energizing electrical load means during a predetermined phase of an alternating current voltage source to prevent erosion of relay contact means during the closure and subsequent bounce of the contact means, by the contact means being of dissimilar materials that resist erosion by the load current arc that is drawn at said predetermined phase of the alternating current voltage source, including: rectifier means adapted to be connected to said alternating current voltage source and having a direCt current output voltage with a superimposed ripple voltage; said rectifier means including means to unbalance said ripple voltage; relay switching means including relay means energized by said output voltage and synchronously switched by a voltage swing of said unbalanced ripple voltage; and said relay means having contact means of dissimilar materials to inhibit contact erosion upon said contact means bouncing during said predetermined phase of said alternating current voltage source; said load means adapted to be energized from said source by the operation of said relay contact means, with said contact means being synchronously operated with said alternating current voltage source by said unbalanced ripple voltage so that said relay contact means bounce during said phase of said source when said contact means resist erosion caused by any load current arc.
Claim 3
Dependent Claim
19 words
A relay control system as described in claim 1 wherein said rectifier means includes a full wave rectifier bridge.
Claim 4
Dependent Claim
17 words
A relay control system as described in claim 2 wherein said bridge unbalancing means is a resistor.
Claim 5
Dependent Claim
20 words
A relay control system as described in claim 3 wherein said relay switching means is a solid state switching circuit.
Claim 6
Dependent Claim
46 words
A relay control system as described in claim 4 wherein said solid state switching circuit includes a unijunction transistor and a capacitor connected to said relay means to energize said relay means when said ripple voltage swing causes said capacitor to discharge through said unijunction transistor.
Claim 7
Dependent Claim
23 words
A relay control system as described in claim 5 wherein said relay contact means has at least one contact generally made of tungsten.
Claim 8
Dependent Claim
17 words
A relay control system as described in claim 1 wherein said bridge unbalancing means is a resistor.
Claim 9
Dependent Claim
20 words
A relay control system as described in claim 7 wherein said relay switching means is a solid state switching circuit.
Claim 10
Dependent Claim
46 words
A relay control system as described in claim 8 wherein said solid state switching circuit includes a unijunction transistor and a capacitor connected to said relay means to energize said relay means when said ripple voltage swing causes said capacitor to discharge through said unijunction transistor.
Claim 11
Dependent Claim
23 words
A relay control system as described in claim 9 wherein said relay control means has at least one contact generally made of tungsten.
References Cited (Backward Citations)
US3372303A
Cited
US3430063A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-02-01 | 1974-08-03 | 1975-02-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-02-01 | 1978-08-03 | 1979-02-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-02-01 | 1982-08-03 | 1983-02-02 | $7700.00 | Window Closed / Lapsed |