Square D Company

Other

William Weizhong Chen

Gary W Scott

Brett E Larson

Andy A Haun

Bruce F Lindholm

Randall L Siebels

Stanley J Brooks

Eldridge R Byron

Frank T Ehrenberger

Kevin James Green

Steven C Wilgenbusch

William Rezac

Ron E Stecker

Colin Cornhill

R Kent Crawford

Matt Sortland

Manzoor Ali

Aaron Bottorff

Lori Dorrell

George D Gregory

The present invention provides an electrical contactor for connecting and disconnecting an electrical power source to an electrical device wherein the electrical power source is electrically connected to a line terminal having a line terminal electrical contact and the electrical device is electrically connected to a load terminal electrical contact. The electrical contactor contains a plurality of electrical contacts which contact the line and load terminal electrical contacts. A positive temperature coefficient resistivity element is electrically connected between at least one of the terminals and the electrical contactor contacts to provide arc suppression during the opening and closing of the electrical contacts

Electrical contactor with positive temperature coefficient resistivity element

An apparatus and method for interrupting the flow of electrical current in a line is disclosed. The invention provides for better limitation of current than can be achieved in the prior art. With effective current limitation, the magnetic force generated by the circuit breaker coil will not be excessive thereby reducing potential damage to the circuit breaker armature, increasing the interruption rating of the circuit breaker and end-use equipment and decreasing the interruption pressure within the circuit breaker.

Circuit breaker including positive temperature coefficient resistivity element and current limiting element

The present invention provides a current limiting circuit breaker having a plurality of current responsive devices for opening a pair of contacts upon short circuit conditions. One such device is a conventional magnetic tripping mechanism. The other device utilizes an insulating object driven by a magnetic force caused by the short circuit current. Upon opening of the contacts with the use of the insulating object, let-through current flows through a secondary contact, positioned on the insulating object, to a positive temperature coefficient resistivity element which limits the current and arcing in the contacts. In an alternative embodiment, at least one steel component is added to increase the magnetic force, thereby providing a greater force on the insulating object. An insulation component is also added to further suppress any arc generated between the contacts when going from a closed state to an open state. In another alternative embodiment, the magnetic tripping mechanism is actuated by the device utilizing the insulating object driven by the magnetic force.

Current limiting circuit breaker with positive temperature coefficient resistivity (PTC) element and insertable insulating object

The present invention provides a current limiting circuit breaker having a current responsive device for opening a pair of contacts or switch upon short circuit conditions. The current responsive device utilizes an insulating object driven by a magnetic force caused by a short circuit current. Upon opening of the contacts with the use of the insulating object, let-through current flows through a secondary contact, positioned on the insulating object, to a positive temperature coefficient resistivity element which limits the current and arcing in the contacts. The PTC elements could be pure metallic materials such as pure tungsten, pure iron, etc. Conductive polymer and ceramic PTC materials could also be used for some specific applications. The present invention also provides a method of electrically connecting a drive plate and a line terminal on the current limiting circuit breaker.

Current limiting circuit breaker

A circuit breaker and method for interrupting the flow of electric current in a line having a load and a source including a first switch connected in series with the line and a first actuating device coupled to the first switch and adapted to be actuated by at least one activating signal, to move the first switch from the closed position to the open position. A resistor having a positive temperature coefficient of resistivity is connected in series with the first switch and a voltage limiting device is connected in parallel with the resistor. A second actuating device is coupled to the first switch and is adapted to be actuated by at least one remote control activating signal, to move the first switch to the open position or to the closed position. The second actuating device further includes a coil and a second switch connected to the coil and to the line, the second switch adapted for activating the coil upon the receipt of the remote control activating signal. A pull bar is connected to the coil and coupled to the first switch wherein the pull bar is adapted to move the first switch to the open position when the coil activated and to the closed position when the coil is not activated.

Remote controllable circuit breakers with positive temperature coefficient resistivity (PTC) elements

A medium to high voltage load circuit interrupter and method for breaking the flow of electric current in a line having a load and a source. A main switch is connected in series with the line. A metal resistor having a positive temperature coefficient of resistivity (PTC element) is connected in series to the arcing switch, wherein the metal resistor and arcing switch are connected in parallel with the main switch. The main switch moves from the closed position to the open position prior to the arcing switch moving from the closed position to the open position. The circuit interrupter further includes an arc chute having a channel and electrically coupled to the arcing switch wherein the arcing switch is positioned within the channel when the arcing switch is in a closed position. In one embodiment, the PTC element is positioned on an insulator positioned between a ground and the main switch and an arcing switch. In another embodiment, the PTC element is positioned within a channel in the arc chute. The PTC element is, for example, in the shape of a serpentine, and is comprised, for example, of a pure metal such as pure tungsten, iron, tantalum or chromium.

Medium to high voltage load circuit interrupters including metal

A circuit breaker for interrupting the flow of electric current in a line includes a switch connected in series with the line, the switch having an open position and a closed position. At least one positive temperature coefficient resistivity element (PTC element) is connected in series with the line. A first magnetic coil is positioned around a yoke, for example, an iron core, and connected in parallel with the PTC element and a second magnetic coil is positioned around the yoke and connected in series with the line and the switch. A voltage limiting device, such as a metal oxide varistor, is connected in parallel with the at least one PTC element. An armature is pivotally mounted in relation to the yoke wherein the yoke and the armature form a magnetic circuit with the first magnetic coil and the second magnetic coil. A trip lever is connected to the armature and the switch, the trip lever effecting movement of the switch from a closed position to an open position wherein the flow of electric current in the line is interrupted. When the first magnetic coil or the second magnetic coil reaches a predetermined current value, the armature is pulled to trip by the magnetic circuit wherein the trip lever is pulled to a tripped position to effect the movement of the switch to an open position wherein the flow of electric current in the line is interrupted.

Circuit breaker including two magnetic coils and a positive temperature

A circuit protection apparatus employs a PTC element for overload and/or short circuit protection and an arcing fault interruption arrangement. The circuit protection apparatus may be employed in a ground fault receptacle for interrupting the flow of electrical current in a line in response to any of a plurality of different types of fault conditions on the line. The circuit protection apparatus may include a set of contacts connected in series with the line, and having an open position and a closed position, a trip device coupled to the contacts, adapted to be actuated by a trip signal, to move the contacts from the closed position to the open position and an element having a positive temperature coefficient of resistivity (PTC) connected in series with the contacts. The PTC element is connected to the trip device to provide the trip signal to the device in response to overload or short circuit conditions in the line. A switching element is operatively coupled with the trip device for providing the trip signal to said device in response to an actuating signal. An arcing fault circuit is adapted for detecting an arcing fault in the line and producing the actuating signal when the arcing fault is detected.

Circuit interrupter with arcing fault protection and PTC (positive

A circuit breaker including a switch having an open and a closed position connected to a line of the circuit breaker. A first actuating device, actuated by a first activating signal, is connected to the switch to move the switch from the closed position to the open position wherein the flow of electric current in the line is interrupted. A positive temperature coefficient resistivity element (PTC element) is tripped at least once wherein the tolerance of the PTC element is reduced and the PTC element is connected to the first actuating device for providing the first activating signal. In another embodiment of the present invention, a second actuating device, actuated by a second activating signal provided by the circuit breaker current, is connected to the switch to move the switch from the closed position to the open position wherein the flow of electric current in the line is interrupted. In another embodiment of the present invention, a plurality of PTC elements are tested to determine a tolerance value for each of the PTC elements and at least two of the PTC elements are matched wherein, when the at least two PTC elements are connected in parallel, the combined tolerance is reduced and wherein the ampere rating for the line is increased. In another embodiment of the present invention, the plurality of PTC elements are tripped at least once before testing and matching to further reduce the tolerance of the PTC elements.

Circuit breaker including positive temperature coefficient resistivity

A Positive Temperature Coefficient Resistivity (PTC) element has a resistivity that increases as the temperature increases. Circuit breakers having PTC elements can achieve better overload and short circuit protection than existing products. Breakers with PTC elements can also be combined with ground fault detection circuits to activate the circuit breaker under ground fault conditions that are less severe than the overcurrent conditions that would normally activate the circuit breaker. A shunt trip assembly incorporating a PTC resistor reduces the required power rating of the clearing switch.

Circuit breakers with PTC (Positive Temperature Coefficient resistivity

Methods of arc suppression connecting a PTC material in parallel with a pair of contacts but in series with a second pair of contacts. The PTC material could be doped-BaTiO.sub.3 -ceramics, conductive polymer, or metallic PTC materials. The two pairs of contacts should be so mechanically associated that the second pair of contacts must be always opened right after the opening of the first pair. It is enough for some applications to connect one pair of contacts in parallel with a polyswitch or BaTiO.sub.3 -ceramics. For medium and high voltage circuit breakers, more than two pairs of contacts may be needed, and all these contacts should be opened sequentially during a circuit interruption. According to the methods, simple structured circuit breakers can be made to protect circuits from a short circuit, an overload and a ground fault. The circuit breaker invented here can provide an electronic alarm signal when a fault current occurs. The principle of the electronic indication of a fault current is applicable to any circuit breakers. By adding a series coil around the same core of the trip coil in a common ground fault circuit interrupter or receptacle, the interrupter or receptacle can be improved to act as a circuit breaker.

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Marion, IA, United States of America

William Weizhong Chen