Panamax Corporation

Illinois Tool Works Inc.

Michael L Hoopes

A surge protection device employing a controlled convection thermal disconnector in which a surge protective component, such as a metal oxide varistor, and a thermally responsive device, such as a thermal cut-off, are placed in separate, cross-ventilated chambers. An internal vent is positioned such that it prevents line-of-sight between the surge protective component and a mechanized portion of the thermally responsive device, in order to protect the thermally responsive device from hot surge protective component emissions from the surge protective component. An output vent is formed between the thermally responsive device and the exterior atmosphere to promote forced convective heat transfer from the surge protective component to the thermally responsive device during a thermal runaway condition, with the expanding gases in the surge protective component chamber providing the transfer impetus.

Controlled convection thermal disconnector

A circuit and device protects connected equipment from a broad range of unsafe conditions of over-voltage and under-voltage by disconnecting the line voltage before surge protection components, generally MOVs, are damaged from sustained surges. However, nuisance tripping of the protective circuit is avoiding by discriminating surges that are properly handled by the MOVs and components in the load or protective device. Further, the devise are protected from sustained high voltage line conditions, which would ordinarily result in repeated cycling between the on and off states as the line voltages fluctuates slightly at or about the trip threshold, as the circuit has a deliberate hysteresis such that the turn on voltage is about 10 to 20 V lower than the shut off threshold.

Unsafe voltage shutoff control

An over-voltage protection circuit for protecting against excessive voltages on the power line, neutral line and ground line. A voltage detection circuit is coupled and monitors the interterminal voltages between the power, neutral and ground lines. A switch circuit, coupled between the power line and load, provides an electrical current path between the power line and load when the voltage detection circuit detects that all of the interterminal voltages are less than a predetermined maximum voltage and the interterminal voltage between the power and neutral line terminals is greater than a predetermined minimum voltage. The switch circuit interrupts this electrical current path when the voltage detection circuit detects that any of the to interterminal voltages is greater than the predetermined maximum voltage. The switch circuit also interrupts this electrical current path when the voltage detection circuit further detects that the interterminal voltage between the power and neutral line terminals is less than the predetermined minimum voltage.

AC voltage protection circuit

A surge protector utilizing MOVs has a capacitor connecting line input to neutral input that causes thermal fuses to sequentially disconnect the line conductor from the output of the protector under limited current abnormal overvoltages either line to ground or neutral to ground.

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Novato, CA, United States of America

Michael L Hoopes