1. Field of the Invention
This invention relates generally to electrical switching apparatus and, more particularly, to electrical switching apparatus, such as circuit breakers. The invention also relates to trip actuator assemblies for circuit breakers.
2. Background Information
Electrical switching apparatus include, for example, circuit switching devices; circuit interrupters, such as circuit breakers; network protectors; contactors; motor starters; motor controllers; and other load controllers. Electrical switching apparatus such as circuit interrupters and, in particular, circuit breakers of the molded case variety, are well known in the art. See, for example, U.S. Pat. No. 5,341,191.
Circuit breakers are used to protect electrical circuitry from damage due to an overcurrent condition, such as an overload condition or a relatively high level short circuit or fault condition. Molded case circuit breakers typically include a pair of separable contacts per phase. The separable contacts may be operated either manually by way of a handle disposed on the outside of the case or automatically in response to an overcurrent condition. Typically, such circuit breakers include an operating mechanism, which is designed to rapidly open and close the separable contacts, a trip unit, which senses overcurrent conditions in an automatic mode of operation, and a trip actuator assembly, which in response to such overcurrent conditions, is actuated by the trip unit to move the operating mechanism to a trip state, thereby moving the separable contacts to their open position. See, for example, U.S. Pat. Nos. 5,910,760; and 6,144,271.
It is sometimes desirable to integrate a new trip unit feature or a new or different type of trip unit into a circuit breaker. For example, it is sometimes desirable to integrate an electronic trip mechanism (e.g., without limitation, a flux shunt trip actuator) into the trip actuator assembly. Whether this is done during the assembly of a new circuit breaker or as a retrofit of an existing circuit breaker, it typically requires that numerous components be fit within the circuit breaker housing, where space is limited. Effectively arranging the trip actuator assembly within the circuit breaker housing such that it works well, yet does not require relatively significant modifications or alterations to the housing or to the circuit breaker in general, is a challenging endeavor.
There is, therefore, room for improvement in electrical switching apparatus, such as circuit breakers, and in trip actuator assemblies therefor.
These needs and others are met by embodiments of the invention, which are directed to a trip actuator assembly for electrical switching apparatus such as, for example, circuit breakers, wherein the trip actuator assembly includes a frame and an interface assembly that enable the trip actuator assembly to operate effectively and to be secured in a desired orientation within a compartment of the circuit breaker housing.
As one aspect of the invention, a trip actuator assembly is provided for an electrical switching apparatus. The electrical switching apparatus comprises a housing, separable contacts enclosed by the housing, and an operating mechanism structured to open and close the separable contacts. The housing includes an exterior, an interior, and a number of compartments disposed within the interior. The trip actuator assembly comprises: a trip actuator comprising an actuating element, the actuating element being structured to move among an unactuated position corresponding to the separable contacts of the electrical switching apparatus being closeable, and an actuated position corresponding to the separable contacts being tripped opened in response to a trip condition; a frame comprising a first end, a second end disposed opposite and distal from the first end, and a mounting portion disposed between the first end and the second end, the trip actuator being disposed at or about the mounting portion of the frame; and an interface assembly movably coupled to the frame, the interface assembly comprising an interface element, the interface element being structured to be disposed between the actuating element of the trip actuator and a portion of the operating mechanism of the electrical switching apparatus. When the actuating element of the trip actuator moves from the unactuated position toward the actuated position in response to the trip condition, the actuating element engages and moves the interface element, thereby moving the operating mechanism to trip open the separable contacts. The frame is structured to secure the trip actuator assembly in a desired orientation within a corresponding one of the number of compartments of the housing.
The interface assembly may further comprise a reset member movably coupled to the frame. The reset member may include a first end structured to be accessible from the exterior of the housing of the electrical switching apparatus, and a second end disposed opposite and distal from the first end of the reset member. The second end of the reset member may be cooperable with the interface element to reset the actuating element of the trip actuator from the actuated position to the unactuated position. The reset member may be a reset button. The reset button may be movable among a first position corresponding to the second end of the reset button not engaging the interface element, and a second position corresponding to the second end of the reset button engaging and moving the interface element, thereby moving the actuating element of the trip actuator toward the unactuated position. The interface assembly may further comprise a biasing element. The biasing element may bias the reset button toward the first position.
The frame may further comprise a first trip actuator restraint and a second trip actuator restraint. The trip actuator may be restrained between the first trip actuator restraint and the second trip actuator restraint, and the mounting portion of the frame may overlay at least a portion of the trip actuator. The first trip actuator restraint may be a first projection extending perpendicularly outwardly from the first end of the frame, and the second trip actuator restraint may be a second projection extending perpendicularly outwardly from the second end of the frame generally opposite the first projection. The first projection may include a tapered end, wherein the tapered end of the first projection is structured to cooperate with a portion of the corresponding one of the number of compartments of the housing of the electrical switching apparatus.
As another aspect of the invention, an electrical switching apparatus comprises: a housing including an exterior, an interior, and a number of compartments disposed within the interior; separable contacts enclosed by the housing; an operating mechanism for opening and closing the separable contacts; and a trip actuator assembly comprising: a trip actuator comprising an actuating element, the actuating element being movable among an unactuated position corresponding to the separable contacts being closeable, and an actuated position corresponding to the separable contacts being tripped opened in response to a trip condition, a frame comprising a first end, a second end disposed opposite and distal from the first end, and a mounting portion disposed between the first end and the second end, the trip actuator being disposed at or about the mounting portion of the frame, and an interface assembly movably coupled to the frame, the interface assembly comprising an interface element, the interface element being disposed between the actuating element of the trip actuator and a portion of the operating mechanism. When the actuating element of the trip actuator moves from the unactuated position toward the actuated position in response to the trip condition, the actuating element engages and moves the interface element, thereby moving the operating mechanism to trip open the separable contacts. The frame secures the trip actuator assembly in a desired orientation within a corresponding one of the number of compartments of the housing.
The operating mechanism may further comprise a trip bar and a generally planar element extending outwardly from the trip bar, and the interface element may include an elongated protuberance. When the actuating element of the trip actuator moves toward the actuated position in response to the trip condition, the elongated protuberance of the interface element may engage and move the generally planar element, thereby pivoting the trip bar and tripping open the separable contacts.
The electrical switching apparatus may be a circuit breaker, and the operating mechanism of the circuit breaker may further comprise a trip unit module. The trip unit module may comprise a sensor structured to sense current flowing through the separable contacts, and a processor structured to output a trip signal to the trip actuator of the trip actuator assembly responsive to the sensed current. When the sensed current is indicative of the trip condition, the trip signal may actuate the actuating element of the trip actuator thereby moving the actuating element to the actuated position to trip open the separable contacts.
A full understanding of the invention can be gained from the following description of the preferred embodiments when read in conjunction with the accompanying drawings in which:
For purposes of illustration, embodiments of the invention are shown and described in association with a trip actuator for a trip unit of a three-pole circuit breaker, although it will become apparent that they are also applicable to a wide range of electrical switching apparatus having any number of poles.
Directional phrases used herein, such as, for example, left, right, top, bottom, up, down, clockwise and counterclockwise and derivatives thereof, relate to the orientation of the elements shown in the drawings and are not limiting upon the claims unless expressly recited therein.
As employed herein, the terms “actuator” and “actuating element” refer to any known or suitable output mechanism (e.g., without limitation, trip actuator; solenoid) for an electrical switching apparatus and/or the element (e.g., without limitation, stem; plunger; lever; paddle; arm) of such mechanism which moves in order to manipulate another component of the electrical switching apparatus.
As employed herein, the term “fastener” shall mean a separate element or elements which is/are employed to connect or tighten two or more components together, and expressly includes, without limitation, rivets, pins, screws, bolts and the combinations of bolts and nuts (e.g., without limitation, lock nuts) and bolts, washers and nuts.
As employed herein, the term “trip condition” refers to any electrical event that results in the initiation of a circuit breaker operation in which the separable contacts of the circuit breaker are tripped open, and expressly includes, but is not limited to, electrical fault conditions such as, for example, current overloads, short circuits, abnormal voltage and other fault conditions, receipt of an input trip signal, and a trip coil being energized.
As employed herein, the statement that two or more parts are “coupled” together shall mean that the parts are joined together either directly or joined through one or more intermediate parts.
As employed herein, the term “number” shall mean one or an integer greater than one (i.e., a plurality).
In the example of
(
As best shown in
The trip actuator assembly 100 further includes a frame 106 having first and second opposing ends 108,110 and a mounting portion 112 disposed therebetween. The trip actuator 102 is disposed at or about the mounting portion 112 of the frame 106, as best shown in
An interface assembly 114 is movably coupled to the frame 106, and includes an interface element 116, which is disposed between the actuating element 104 of the trip actuator 102 and a portion (see, for example, trip bar plate 20 of
The interface assembly 114 of the example trip actuator assembly 100 further includes a reset button 118, which is movably coupled to the frame 106 of the trip actuator assembly 100 at or about the second end 110 thereof. The reset member, which in the example shown and described herein is a reset button 118, includes a first end 120, which is accessible from the exterior 6 of the circuit breaker housing 4, as shown in
To facilitate the above operation upon actuation of the reset button 118, the interface element 116 includes an arcuate interface surface 134, and the second end 122 of the reset button 118 includes a corresponding arcuate actuating surface 136. When the reset button 118 is moved (e.g., downward from the perspective of
As best shown in
Accordingly, the disclosed trip actuator assembly 100 provides a relatively compact sub-assembly, which fits in a desired orientation within a corresponding compartment 10 (
While specific embodiments of the invention have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limiting as to the scope of the invention which is to be given the full breadth of the claims appended and any and all equivalents thereof.
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Number | Date | Country | |
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20100085136 A1 | Apr 2010 | US |