US4068281A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thermally responsive metal oxide varistor transient suppression circuit
Assignee: General Electric Co
•
Filing: 1976-09-15
•
Granted: 1978-01-10
•
Expires: 1996-09-15
Abstract
Abstract A temperature responsive resistor is thermally connected to a body of metal oxide varistor material in transient suppression and other applications. In the event of excess energy dissipation in the varistor, the temperature of the thermally responsive resistor increases to provide a trigger signal to a triac or other similar electronic switch which may be utilized to provide an alarm, provide increased cooling to the varistor body, to divert, or limit current flow from the varistor. Current flow through the temperature responsive resistor may be provided from a third terminal on the metal oxide varistor in which case the circuit is responsive to both total energy dissipation and peak energy dissipation levels in the varistor.
Inventors
- 👤 John D. Harnden, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 18:46
CPC Classifications
H; H02; H02H; H02H9/00; H02H9/04; H02H9/043; H01; H01C; H01C7/00; H01C7/10; H01C7/12; H02H5/00; H02H5/04; H02H5/042
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
70 words
An electrical circuit comprising in combination: a body of metal oxide varistor material having at least two electrodes affixed thereto, and temperature responsive means thermally connected to said body of varistor material which means function to actuate an electrical switch, connected as a crowbar in shunt with two of said electrodes on said body of varistor material, at such times as the temperature of said body exceeds a predetermined level.
Claim 2
Dependent Claim
70 words
An electrical circuit comprising in combination: a body of metal oxide varistor material having at least two electrodes affixed thereto, and temperature responsive means thermally connected to said body of varistor material which means function to actuate an electrical switch, connected as a crowbar in shunt with two of said electrodes on said body of varistor material, at such times as the temperature of said body exceeds a predetermined level.
Claim 3
Dependent Claim
18 words
The circuit of claim 1 wherein said temperature responsive means includes a resistor having a positive temperature coefficient.
Claim 4
Dependent Claim
22 words
The circuit of claim 2 wherein said resistor is electrically connected between the gate and the cathode of a semiconductor switching device.
Claim 5
Dependent Claim
18 words
The circuit of claim 1 wherein said temperature responsive means includes a resistor having a negative temperature coefficient.
Claim 6
Dependent Claim
21 words
The circuit of claim 4 wherein said resistor is connected between the anode and the gate of a semiconductor switching device.
Claim 7
Dependent Claim
140 words
An electrical circuit comprising, in combination: a body of metal oxide varistor material; temperature responsive means, including a resistor having a negative temperature coefficient, thermally connected to said body of varistor material, which means function to actuate an electrical switch at such times as the temperature of said body exceeds a predetermined level; first and second electrodes disposed on the surface of said body of metal oxide varistor material and adapted for connection to a source of electric potential; a third electrode disposed on the surface of said body of metal oxide varistor material, intermediate said first and second electrodes, and connected to a first terminal of said resistor; and a semiconductor switching device having an anode connected to said first electrode, a cathode connected to said second electrode and a gate connected to a second terminal of said resistor.
Claim 8
Dependent Claim
140 words
An electrical circuit comprising, in combination: a body of metal oxide varistor material; temperature responsive means, including a resistor having a negative temperature coefficient, thermally connected to said body of varistor material, which means function to actuate an electrical switch at such times as the temperature of said body exceeds a predetermined level; first and second electrodes disposed on the surface of said body of metal oxide varistor material and adapted for connection to a source of electric potential; a third electrode disposed on the surface of said body of metal oxide varistor material, intermediate said first and second electrodes, and connected to a first terminal of said resistor; and a semiconductor switching device having an anode connected to said first electrode, a cathode connected to said second electrode and a gate connected to a second terminal of said resistor.
Claim 9
Dependent Claim
59 words
An electrical circuit element comprising in combination a body of varistor material having attached thereto a first terminal, a second terminal, and a third terminal disposed intermediate said first terminal and said second terminal; and a positive temperature coefficient resistor thermally connected to said body of varistor material and electrically connected between said first terminal and said third terminal.
Claim 10
Dependent Claim
59 words
An electrical circuit element comprising in combination a body of varistor material having attached thereto a first terminal, a second terminal, and a third terminal disposed intermediate said first terminal and said second terminal; and a positive temperature coefficient resistor thermally connected to said body of varistor material and electrically connected between said first terminal and said third terminal.
Claim 11
Dependent Claim
24 words
The circuit element of claim 7 in combination with a source of transient electrical power connected across said first terminal and said second terminal.
Claim 12
Dependent Claim
96 words
A varistor circuit element with temperature limiting characteristics comprising: a body of metal oxide varistor material; at least one body of positive temperature coefficient resistor material bonded to a surface of said body of metal oxide varistor material; and electrode means disposed on the surfaces of said bodies which function to direct applied electric currents through a series circuit formed by said body of varistor material and at least one of said bodies of resistor material; whereby current flow in said body of metal oxide varistor material is limited to prevent excessive temperatures in said material.
Claim 13
Dependent Claim
96 words
A varistor circuit element with temperature limiting characteristics comprising: a body of metal oxide varistor material; at least one body of positive temperature coefficient resistor material bonded to a surface of said body of metal oxide varistor material; and electrode means disposed on the surfaces of said bodies which function to direct applied electric currents through a series circuit formed by said body of varistor material and at least one of said bodies of resistor material; whereby current flow in said body of metal oxide varistor material is limited to prevent excessive temperatures in said material.
References Cited (Backward Citations)
US3564293A
Cited
US3600650A
Cited
US3622849A
Cited
US3742419A
Cited
US3754200A
Cited
US3818411A
Cited
US3708720A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-01-09 | 1981-07-11 | 1982-01-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-01-09 | 1985-07-11 | 1986-01-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-01-09 | 1989-07-11 | 1990-01-10 | $7700.00 | Window Closed / Lapsed |