Circuit protection device

Abstract

A voltage suppression device for suppressing voltage surges in an electrical circuit, comprised of a voltage sensitive element having a predetermined voltage rating, the voltage sensitive element increasing in temperature as voltage applied across the voltage sensitive element exceeds the voltage rating. Terminals are provided for electrically connecting the voltage sensitive element between a power line of an electrical circuit and a ground or neutral line of the electrical circuit. A normally closed, thermal switch is electrically connected in series with the voltage sensitive element between the power line and the voltage sensitive element, the thermal switch being thermally coupled to the voltage sensitive element wherein the thermal switch moves from a normally closed position to an open position to form a gap between the thermal switch and the voltage sensitive element when the temperature of the voltage sensitive element reaches a level indicating an over-voltage condition. A non-conductive barrier that is operable to move into the gap when the thermal switch moves to an open position, the barrier preventing line voltage surges from arcing between the thermal switch and the voltage sensitive element.

Description

[0001]This application is a continuation-in-part of application Ser. No. 09 / 093,367, filed on Jun. 8, 1998, now U.S. Pat. No. 6,040,971.FIELD OF THE INVENTION[0002]The present invention relates generally to circuit protection devices, and more particularly to a device that suppresses transient current / voltage surges.BACKGROUND OF THE INVENTION[0003]Many of today's highly sensitive electronic components, such as computer and computer-related equipment, that are used in commercial and residential applications contain transient voltage surge suppression (TVSS) devices. These devices protect sensitive and / or expensive electronic circuits and components from damage from over-voltage fault conditions. Such transient voltage surge suppression systems are typically designed for moderate fault conditions expected in normal use. In this respect, such systems are designed to suppress relatively minor fault conditions, but are not designed to protect against major over-voltage conditions. Examp...

AI Technical Summary

Benefits of technology

[0009]In accordance with another aspect of the present invention, there is provided a voltage suppression device for suppressing voltage surges in an electrical circuit. The device is comprised of a voltage sensitive element having a predetermined voltage rating. The voltage sensitive element increases in temperature as voltage applied across the voltage sensitive element exceeds the voltage rating. Terminals electrically connect the voltage sensitive element between a power line of an electrical circuit and a ground or neutral line of the electrical circuit. A normally closed, thermal switch is electrically connected in series with the voltage sensitive element between the power line and the voltage sensitive element. The thermal switch is thermally coupled to the voltage sensitive element wherein the thermal switch moves from a normally closed position to an open position to form a gap between the thermal switch and the voltage sensitive element when the temperature of the voltage sensitive element reaches a level indicating an over-voltage condition. A non-conductive barrier is operable to move into the gap when the thermal switch moves to an open position. The barrier prevents line voltage surges from arcing between the thermal switch and the voltage sensitive element.

[0010]It is an object of the present invention to provide a circuit protection device to protect sensitive circuit components and systems from current and voltage surges.

[0011]It is another object of the present invention to provide a circuit protection device as described above to prevent catastrophic failure of a transient voltage surge suppression (TVSS) system within a circuit that may occur from repetitive circuit faults or from a single fault of excessive proportion.

[0015]A still further object of the present invention is to provide a circuit protection device as described above that is modular in design and easily replaceable in a circuit.

Problems solved by technology

Such an over-voltage causes the voltage sensitive element to heat the thermal element beyond its softening point.

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