Electrical switching apparatus and trip assembly therefor

A trip assembly is for an electrical switching apparatus. The electrical switching apparatus includes a housing, a reset assembly, an electrical communication assembly, separable contacts, and an operating mechanism for opening and closing the separable contacts. The operating mechanism includes a trip bar and a crossbar. The trip assembly includes: a mounting assembly coupled to the housing; an actuating element coupled to the mounting assembly, the actuating element being electrically connected to the electrical communication assembly; a trip cam coupled to the mounting assembly, the trip cam cooperating with the reset assembly in order to reset the actuating element; and an indication assembly coupled to the mounting assembly. The actuating element is structured to drive the trip cam into the trip bar in order to trip open the separable contacts. The actuating element cooperates with the indication assembly to electrically communicate a circuit status to the electrical communication assembly.

BACKGROUND

The disclosed concept pertains generally to electrical switching apparatus, such as, for example, circuit breakers. The disclosed concept also pertains to trip assemblies for electrical switching apparatus.

2. Background Information

Electrical switching apparatus are used to protect electrical circuitry from damage due to a trip condition, such as, for example, an overcurrent condition, an overload condition, an undervoltage condition, a relatively high level short circuit or fault condition, a ground fault or arc fault condition. Molded case circuit breakers, for example, include at least one pair of separable contacts which are operated either manually by way of a handle disposed on the outside of the case, or automatically by way of a trip unit in response to the trip condition.

Known trip units take up significant space within the circuit breaker. As a result of the lack of available space, it is difficult to determine whether the separable contacts are open or closed. That is, little or no space is available for a readily visible trip indicator or status indicator for quickly and easily determining the breaker status.

There is, therefore, room for improvement in electrical switching apparatus and in trip assemblies therefor.

SUMMARY

These needs and others are met by embodiments of the disclosed concept, which are directed to an electrical switching apparatus and trip assembly therefor which, among other benefits, electrically communicates a circuit status while being able to trip the electrical switching apparatus.

In accordance with one aspect of the disclosed concept, a trip assembly for an electrical switching apparatus is provided. The electrical switching apparatus includes a housing, a reset assembly coupled to the housing, an electrical communication assembly coupled to the housing, separable contacts enclosed by the housing, and an operating mechanism for opening and closing the separable contacts. The operating mechanism includes a trip bar and a crossbar. The trip assembly comprises: a mounting assembly structured to be coupled to the housing; an actuating element coupled to the mounting assembly, the actuating element being structured to be electrically connected to the electrical communication assembly; a trip cam coupled to the mounting assembly, the trip cam being structured to cooperate with the reset assembly in order to reset the actuating element; and an indication assembly coupled to the mounting assembly. The actuating element is structured to drive the trip cam into the trip bar in order to trip open the separable contacts. The actuating element cooperates with the indication assembly in order to electrically communicate a circuit status to the electrical communication assembly.

In accordance with another aspect of the disclosed concept, an electrical switching apparatus is provided. The electrical switching apparatus comprises: a housing; a reset assembly coupled to the housing; an electrical communication assembly coupled to the housing; separable contacts enclosed by the housing; an operating mechanism for opening and closing the separable contacts, the operating mechanism including a trip bar and a crossbar; and a trip assembly comprising: a mounting assembly coupled to the housing, an actuating element coupled to the mounting assembly, the actuating element being electrically connected to the electrical communication assembly, a trip cam coupled to the mounting assembly, the trip cam cooperating with the reset assembly in order to reset the actuating element, and an indication assembly coupled to the mounting assembly. The actuating element is structured to drive the trip cam into the trip bar in order to trip open the separable contacts. The actuating element cooperates with the indication assembly in order to electrically communicate a circuit status to the electrical communication assembly.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

For purposes of the description hereinafter, directional phrases used herein such as, for example, “clockwise”, “counterclockwise”, “up”, “down”, and derivatives thereof shall relate to the disclosed concept, as it is oriented in the drawings. It is to be understood that the specific elements illustrated in the drawings and described in the following specification are simply exemplary embodiments of the disclosed concept. Therefore, specific orientations and other physical characteristics related to the embodiments disclosed herein are not to be considered limiting with respect to the scope of the disclosed concept.

As employed herein, the statement that two or more parts are “connected” or “coupled” together shall mean that the parts are joined together either directly or joined through one or more intermediate parts.

As employed herein, the statement that two or more parts or components “engage” one another shall mean that the parts touch and/or exert a force against one another either directly or through one or more intermediate parts or components.

FIGS. 1 through 5show an electrical switching apparatus (e.g., without limitation, molded case circuit breaker2) in accordance with a non-limiting embodiment of the disclosed concept. The example circuit breaker2includes a housing4, a reset assembly5, an electrical communication assembly8(shown in simplified form inFIGS. 3 through 5), a pair of separable contacts18(shown in simplified form inFIG. 4) enclosed by the housing4, and an operating mechanism20(shown in simplified form inFIG. 4) for opening and closing the separable contacts18. The reset assembly5and the electrical communication assembly8are coupled to the housing4. The operating mechanism20includes a trip bar14(FIG. 4) and a crossbar16(FIG. 4). As will be discussed in greater detail below, the circuit breaker2further includes a trip assembly100that advantageously operates to trip the separable contacts18, while simultaneously electrically communicating a circuit status to the electrical communication assembly8. In this manner, existing space within the circuit breaker2is utilized by the single subassembly (i.e., the trip assembly100) not only to trip the separable contacts18, but also to electrically communicate the circuit status to the electrical communication assembly8, thereby allowing operators to know whether the separable contacts18are open or closed.

FIGS. 6 and 7show exploded views of the trip assembly100. As shown, the trip assembly100preferably includes a mounting assembly102, an indication assembly120, an actuating element (e.g., without limitation, solenoid150), and a trip cam160. The indication assembly120, the solenoid150, and the trip cam160are each coupled to the mounting assembly102. The indication assembly120includes a biasing element (e.g., without limitation, spring121), a plunger member122and a number of auxiliary switches130,140. The plunger member122partially extends into the mounting assembly102. Each of the auxiliary switches130,140includes a respective body portion132,142and a respective number of holes (see, for example, two holes134,136for the body portion132, and two holes144,146for the body portion142). Each of the auxiliary switches130,140further includes a respective deflection member (see, for example, deflection member138(FIG. 6) located on the body portion132). In operation, the plunger member122is structured to move between each of the auxiliary switches130,140in order to actuate each of the auxiliary switches130,140, thereby causing each of the respective deflection members138(and the respective deflection member of the auxiliary switch140, not shown) to move inwardly with respect to the respective body portion132,142. In this manner, and as will be discussed below, responsive to the plunger member122moving between each of the auxiliary switches130,140, each of the auxiliary switches advantageously sends a signal to the electrical communication assembly8(FIGS. 3-5) to electrically communicate the circuit status.

The mounting assembly102includes a number of mounting members (see, for example, two mounting members104,106) that contain the indication assembly120, the solenoid150, and the trip cam160. The mounting members104,106are each coupled to the housing4of the circuit breaker2. The mounting member104includes a body108and a number of protrusions (see, for example, two protrusions110,112) extending from the body108. In operation, each of the protrusions110,112extends into a corresponding one of the holes144,146of the auxiliary switch140in order to couple the auxiliary switch140to the mounting member104of the mounting assembly102. Similarly, the mounting member104further includes another number of protrusions (not shown) that extend into the holes134,136in order to couple the auxiliary switch130to the mounting member104.

Continuing to refer toFIGS. 6 and 7, the mounting member106includes a body114and a number of protrusions (see, for example, two protrusions116,118) extending from the body114. It will be appreciated that the protrusions116,118extend into the mounting member104in order to couple the mounting members104,106to each other, for example, by a snap-fit mechanism, without the need to employ separate fastening members. In this manner, the mounting members104,106advantageously operate to hold and contain the spring121, the plunger member122, the auxiliary switches130,140, the solenoid150, and the trip cam160.

The solenoid150includes a body152and an extension member154extending from the body152. The trip cam160includes a number of recessed retaining portions161,162, a transfer leg163, a driving leg164and a reset leg165. The trip cam160is preferably made of a single piece of material (e.g., without limitation, an injection molded piece), thereby simplifying manufacturing and reducing cost. Additionally, each of the transfer leg163, the driving leg164and the reset leg165extends away from each of the retaining portions161,162.

FIGS. 8 and 9show different views of the trip cam160. As shown inFIG. 9, the retaining portion161is located opposite and distal from the retaining portion162. The driving leg164is located opposite and distal from the reset leg165. The driving leg164extends from the retaining portion162. The reset leg165extends from the retaining portion161. The transfer leg163is located between and is spaced from the driving leg164and the reset leg165. The transfer leg163is located between and is spaced from each of the retaining portions161,162.

FIG. 10shows an isometric view of the plunger member122. As shown, the plunger member122includes a planar portion123and a cylindrical-shaped receiving portion124located adjacent and perpendicular to the planar portion123. It will be appreciated that the spring121(FIGS. 6 and 7) engages the planar portion123and is located in the receiving portion124. It will further be appreciated that the spring121engages the mounting member104in order to bias the plunger member122away from the auxiliary switches130,140and toward engagement with the crossbar16, as will be discussed below.

FIG. 11shows an assembled view of the trip assembly100. As shown, each of the retaining portions161,162is pivotably coupled to the mounting assembly102, thus allowing the trip cam160to rotate independently with respect to the mounting assembly102. Furthermore, the extension member154is aligned with (i.e., structured to engage and thereby drive) the transfer leg163of the trip cam160. Responsive to a trip condition (e.g., without limitation, an overload condition), a main printed circuit board10(shown in simplified form inFIGS. 3 through 5) sends an electrical signal to the solenoid150, which causes the extension member154to rapidly move away from the body152. As a result, the extension member154of the solenoid150drives the transfer leg163of the trip cam160, thus causing the trip cam160to rotate. Similarly, because the retaining portions161,162are pivotably coupled to the mounting assembly102, when extension member154drives the transfer leg163, each of the driving leg164and the reset leg165likewise rotates together with the transfer leg163.

Referring again toFIG. 4, in operation, when the trip cam160rotates in response to a trip condition, the driving leg164advantageously causes the separable contacts18to trip open and the auxiliary switches130,140to electrically communicate the circuit status to the electrical communication assembly8. More precisely, when the trip cam160rotates in a first direction166in response to a trip condition, the driving leg164engages and drives the trip bar14in a second direction15opposite the first direction166. In the depicted orientation ofFIG. 4, the first direction166is clockwise, and the second direction15is counterclockwise. In other words, the solenoid150drives the trip cam160into the trip bar14in order to trip open the separable contacts18.

At the same time as the operating mechanism20trips open the separable contacts18(i.e., simultaneously), the operating mechanism20drives the plunger member122between the auxiliary switches130,140. More specifically, when the trip bar14rotates in the direction15, the crossbar16drives the plunger member122in a direction125between the auxiliary switches130,140. As stated above, the spring121(FIGS. 6 and 7) biases the plunger member122away from the auxiliary switches130,140and toward engagement with the crossbar16. The force of the spring121on the plunger member122is relatively strong in order that when the circuit breaker2moves from the OFF position to the ON position, the plunger member122advantageously does not get stuck. Thus, the spring121exerts a force on the plunger member122in a first direction155, which in the depicted orientation ofFIG. 4, is down. Before a trip condition (i.e., when the separable contacts18are closed and the circuit breaker2is in an ON position), the spring121, which is fixed at one end by the mounting member104, forces the plunger member122into a position in which it allows the deflection members138(FIGS. 6 and 7) (and the deflection member of the auxiliary switch140(not shown)) to be fully extended outwardly with respect to the respective body portions132,142.

Continuing to refer toFIG. 4, the solenoid150(not shown inFIG. 4) cooperates with the indication assembly120in order to electrically communicate the circuit status to the electrical communication assembly8. It will be appreciated that when the solenoid150(not shown inFIG. 4) moves in the first direction155, the plunger member122moves in the second direction125opposite the direction155in order to electrically communicate the circuit status to the electrical communication assembly8. In the depicted orientation ofFIG. 4, the second direction125is up. When the separable contacts18trip open, the crossbar16rotates in the direction15, thereby exerting a force on and moving the plunger member122in the direction125. When the plunger member122moves in the direction125, the plunger member122causes (i.e., engages, drives, deflects) each of the deflection members138(FIGS. 6 and 7) (and the deflection member of the auxiliary switch140(not shown)) to deflect inwardly with respect to the respective body portion132,142.

Additionally, the electrical communication assembly8includes the main printed board10and a customer interface12(shown in simplified form) each coupled to the housing4. The customer interface12is an external control module (e.g., without limitation, a control light), for customer monitoring of the circuit breaker2. The auxiliary switch130and the solenoid150are each electrically connected to the main printed circuit board10. The auxiliary switch140is electrically connected to the customer interface12. When the deflection member138(FIGS. 6 and 7) deflects inwardly with respect to the respective body portion132, the auxiliary switch130sends an electrical signal to the main printed circuit board10, thereby electrically communicating the circuit status to the main printed circuit board10. Similarly, when the deflection member (not shown) of the auxiliary switch140deflects inwardly with respect to the body portion142, the auxiliary switch140sends an electrical signal to the customer interface12, thereby electrically communicating the circuit status to the customer interface12.

Thus, the trip assembly100advantageously operates to trip the separable contacts18, while simultaneously electrically communicating the circuit status to the main printed circuit board10and the customer interface12. Stated differently, the trip assembly100is a multifunctional subassembly100that trips the separable contacts18and electrically communicates the circuit status. In this manner, operators do not need to disassemble components of the circuit breaker2in order to determine whether the separable contacts18are open or closed. This improves safety in situations where typical mechanisms for determining circuit status, such as the operating handle6position, fail to provide accurate indications of circuit status. Additionally, existing space within the circuit breaker2is advantageously utilized to accommodate the trip assembly100, thereby reducing cost. Furthermore, as this is an electronic trip unit, the resulting instantaneous tripping advantageously provides more protection of the circuit.

In order to reset the circuit breaker2, the circuit breaker2further includes the reset assembly5coupled to the housing4. The reset assembly5includes an operating handle6(FIGS. 1 and 3-5) and a reset pin7(FIGS. 2, 5 and 13) coupled to the operating handle6. The operating handle6extends into the housing4.FIGS. 12 and 13show enlarged views of portions ofFIGS. 1 and 2, respectively. It will be appreciated that the reset pin7(FIGS. 2, 5 and 13) terminates proximate and is structured to drive the reset leg165(FIGS. 1, 5-9 and 11-12). More specifically, and with reference toFIG. 5, movement of the operating handle6(such as, for example, when an operator manually closes the separable contacts18(FIG. 4)) causes the reset pin7to rotate the reset leg165in a direction167. In the depicted orientation, the direction167is counterclockwise, and is opposite the direction166. Referring toFIG. 11, when the reset leg165rotates in the direction167, the transfer leg163drives the extension member154of the solenoid150inwardly with respect to the body152, thereby resetting the solenoid150. Thus, the reset assembly5cooperates with the trip cam160in order to reset the solenoid150.

Furthermore, the disclosed concept is not limited to the auxiliary switches130,140sending the desired signals to the electrical communication assembly8in response to movement of the plunger member122, as described hereinabove.FIG. 14shows another example trip assembly100′ having an indication assembly120′. The indication assembly120′ includes a plunger member122′, the auxiliary switch140, and an auxiliary switch130′. The auxiliary switch130′ includes a first electrical contact strip131′ and a second electrical contact strip132′. The second contact strip132′ is electrically connected to a main printed circuit board10′ (shown in simplified form). The plunger member122′ is substantially the same as the plunger member122, described hereinabove, except that it is connected to the first contact strip131′. As a result of this connection, and the fact that the plunger member122′ moves (i.e., due to the crossbar16(FIG. 4)), the first contact strip131′ moves between positions.

As shown inFIG. 14, and in the enlarged view ofFIG. 15, the contact strips131′,132′ are engaging each other. However, when the plunger member122′ moves, the first contact strip131′ moves away from the second contact strip132′ and is spaced therefrom. As shown inFIG. 16, the first contact strip131′ is spaced from the second contact strip132′. The changing of positions between engagement (FIGS. 14 and 15) and disengagement (FIG. 16) of the contact strips131′,132′ operates as an auxiliary switch to provide indication to the main printed circuit board10′ of circuit status. In other words, when the plunger member122′ is driven into the auxiliary switch140by the crossbar16, the first contact strip131′ moves away from the second contact strip132′, thereby electrically communicating the circuit status to the main printed circuit board10′. Additionally, the indication assembly120′ is advantageous in that the auxiliary switch130′ is relatively inexpensive to manufacture/assemble, while still providing a reliable indication of circuit status to the main printed circuit board10′.

Accordingly, it will be appreciated that the disclosed concept provides for an improved (e.g., without limitation, safer, more efficient in terms of utilization of space, multifunctional) electrical switching apparatus2and trip assembly100therefor, which among other benefits, utilizes existing space within the circuit breaker2to electrically communicate a circuit status to an electrical communication assembly8, while simultaneously tripping a pair of separable contacts18.