Abstract:
An electrical switching apparatus comprising: a stationary contact disposed on a conductive path through the electrical switching apparatus; a rotary contact assembly including a roller and a rotary contact disposed on the surface of the roller, the rotary contact being disposed on the conductive path through the electrical switching apparatus; and an operating mechanism configured to initiate a rotation of the roller, wherein the roller is configured to rotate between a first rested state where the stationary contact and the rotary contact are electrically connected and a second rested state where the stationary contact and the rotary contact are electrically disconnected.

Description:
BACKGROUND 
     1. Field 
     The disclosed concept relates generally to electrical switching apparatuses and, more particularly, to circuit interrupters. 
     2. Background Information 
     One type of electrical switching apparatus is a circuit interrupter. Circuit interrupters, such as for example and without limitation, circuit breakers, are typically used to protect electrical circuitry from damage due to an overcurrent condition, such as an overload condition, a short circuit, or another fault condition, such as an arc fault or a ground fault. Circuit breakers typically include primary separable contacts. The primary separable contacts may be operated either manually by way of a handle disposed on the outside of the case or automatically in response to a detected fault condition. Typically, such circuit breakers include an operating mechanism, which is designed to rapidly open and close the primary separable contacts, and a trip mechanism, such as a trip unit, which senses a number of fault conditions to trip the breaker automatically. Upon sensing a fault condition, the trip unit trips the operating mechanism to a trip state, which moves the separable contacts to their open position. 
     One type of circuit breaker is a remote circuit breaker. Remote circuit breakers typically include separable contacts which may be operated by a controller. In some remote circuit breakers, the separable contacts are provided as secondary separable contacts operated by the controller along with primary separable contacts operated by a trip unit. Remote circuit breakers can be used, for example, to control lights in stores and office buildings that must turn on or off at certain times of the day. Those times can be programmed into the controller that operates the secondary contacts. 
     In one remote circuit breaker configuration, coupling and uncoupling of the separable contacts is controlled through the operation of a bi-directional solenoid. The bi-directional solenoid is operated in a first direction to push an operating mechanism to uncouple the separable contacts, and then the bi-directional solenoid is operated in a second opposite direction to pull the operating mechanism to couple the separable contacts. 
     Bi-directional solenoids require two sets of coils around an actuator in order to support bi-direction operation. Uni-directional solenoids, on the other hand, only require a single set of coils around the actuator. In applications where space is limited (e.g., without limitation, small or miniature circuit breakers), the space for a solenoid is limited, and thus, the total number of coils that can be wrapped around the actuator in the solenoid is limited. Given the same total number of coils around the actuator and the same amount of power, a uni-directional solenoid is able to operate the actuator with more force than a bi-directional solenoid because all the coils in the uni-directional solenoid can be used to apply force to the actuator in a single direction. However, a uni-directional solenoid is not suitable for use with the above-described remote circuit breaker because the operating mechanism requires both pushing and pulling. 
     There is room for improvement in electrical switching apparatuses. 
     There is also room for improvement in circuit interrupters. 
     SUMMARY 
     These needs and others are met by embodiments of the disclosed concept, which provides an electrical switching apparatus including a rotary contact assembly. 
     In accordance with embodiments of the disclosed concept, an electrical switching apparatus comprises: a stationary contact disposed on a conductive path through the electrical switching apparatus; a rotary contact assembly including a roller and a rotary contact disposed on the surface of the roller, the rotary contact being disposed on the conductive path through the electrical switching apparatus; and an operating mechanism configured to initiate a rotation of the roller, wherein the roller is configured to rotate between a first rested state where the stationary contact and the rotary contact are electrically connected and a second rested state where the stationary contact and the rotary contact are electrically disconnected. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A full understanding of the disclosed concept can be gained from the following description of the preferred embodiments when read in conjunction with the accompanying drawings in which: 
         FIGS. 1-3  are isometric views of an electrical switching apparatus in accordance with an example embodiment of the disclosed concept; 
         FIGS. 4-6  are elevation views of the electrical switching apparatus shown in  FIGS. 1-3 ; and 
         FIG. 7  is an elevation view of a rotary contact in accordance with an example embodiment of the disclosed concept. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Directional phrases used herein, such as, for example, left, right, front, back, top, bottom 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 term “fastener” refers to any suitable connecting or tightening mechanism expressly including, but not limited to, screws, bolts and the combinations of bolts and nuts (e.g., without limitation, lock nuts) and bolts, washers and nuts. 
     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). 
       FIG. 1  shows an electrical switching apparatus  1  such as, for example and without limitation, a circuit interrupter and/or a circuit breaker. The electrical switching apparatus  1  includes a rotary contact assembly  10  disposed therein. The rotary contact assembly  10  includes a roller  11  which is disposed on a conductive axle  12 . The roller  11  is configured to rotate (e.g., counterclockwise in the direction of arrow  100 , from the perspective of  FIG. 1 ) with respect to the electrical switching apparatus  1 . The roller  11  may rotate about the conductive axle  12  (i.e., independently with respect to the axle) or it may rotate in conjunction with the conductive axle  12 . The roller  11  may be made of any suitable electrically insulating material. 
     The rotary contact assembly  10  also includes a conductive rotary contact  13  which is disposed on the surface of the roller  11 . The rotary contact  13  is structured to rotate in conjunction with the roller  11 . The rotary contact  13  is electrically connected with the conductive axle  12 . The rotary contact  13  can be electrically connected with the conductive axle  12  by any suitable means. For example and without limitation, the rotary contact  13  may include a conductive protruding member  14  that extends through the roller  11  and couples with the conductive axle  12 , as shown in  FIG. 7 . In one example embodiment, the protruding member  14  can also include a brush (not shown) that contacts the conductive axle  12  so as to form an electrical connection between the rotary contact  13  and the conductive axle  12  while allowing the roller and rotary contact  13  to rotate with respect to the conductive axle  12 . 
     In  FIG. 1 , the rotary contact assembly  10  is in a first rested state where the rotary contact  13  is in contact with a stationary contact  30  included in the electrical switching apparatus  1 . The stationary contact  30 , the rotary contact  13 , and the conductive axle  12  form a conductive path through the circuit interrupter. In  FIG. 2 , the rotary contact assembly  10  is in a partially rotated state. In the partially rotated state, the rotary contact  13  is separated from the stationary contact  30  and the conductive path through the circuit interrupter is broken. From the partially rotated state shown in  FIG. 2 , the rotary contact assembly  10  continues to rotate to a second rested state which is shown in  FIG. 3 . In the second rested state ( FIG. 3 ), the rotary contact assembly  10  is rotated about 180° with respect to the first rested state ( FIG. 1 ) and the insulating roller  11  is disposed between the stationary contact  20  and the rotary contact  13 . 
     To initiate rotation of the rotary contact assembly  10  from the first rested state to the second rested state, a solenoid  31  included in the electrical switching apparatus  1  is operated. The solenoid  31  includes an actuator  32  that extends and interacts with a paddle member  15  included on the rotary contact assembly  10 , thus causing the rotary contact assembly  10  to move laterally away from the stationary contact  30  and to rotate, as shown in  FIG. 2 . A first operation of the solenoid  31  causes the rotary contact assembly  10  to rotate from the first rested state ( FIG. 1 ), through the partially rotated state, shown in  FIG. 2 , and into the second rested state of  FIG. 3 . A second subsequent operation then causes the solenoid  31  to rotate, in the opposite direction, from the second rested state ( FIG. 3 ), through another partially rotated state, and into the first rested state of  FIG. 1 . 
     Referring to  FIG. 1 , the paddle member  15  extends from the conductive axle  12 . The paddle member  15  includes a first paddle member  16  which extends in a first direction from the conductive axle  12  and a second paddle member  17  which extends from the conductive axle  12  in a second direction which is opposite of the first direction. When the solenoid  31  is operated to rotate the rotary contact assembly  10  from the first rested state ( FIG. 1 ) to the second rested state ( FIG. 3 ), the actuator  32  presses against the first paddle member  16 , as shown in phantom line drawing in  FIG. 1 . When the solenoid  31  is operated to rotate the rotary contact assembly  10  from the second rested state ( FIG. 3 ) to the first rested state, the actuator  32  presses against the second paddle member  17 , as shown in phantom line drawing in  FIG. 3 . 
     The paddle member  15  may be configured to rotate about the conductive axle  12  or in conjunction with the conductive axle  12 . The paddle member  15  is structured to rotate in conjunction with the roller  11 . In the example embodiment shown in  FIG. 1 , the paddle member  15  is directly coupled with the roller  11 . In another example embodiment, the roller  11  and the paddle member  15  are both configured to rotate in conjunction with the conductive axle  12 , but are not directly coupled with each other. However, rotation of the paddle member  15  causes rotation of the conductive axle  12 , which in turn causes rotation of the roller  11 . 
     Referring now to  FIG. 4 , the electrical switching apparatus  1  also includes a guide slot  40  and the rotary contact assembly  10  includes a guide member  18  disposed on the conductive axle  12 . The guide member  18  is structured to fit into the guide slot  40 . The guide member  18  has a major axis  19  and a minor axis  20 , and the length of the major axis  19  is greater than the length of the minor axis  20 . 
     The guide slot  40  is structured to receive the guide member  18 . The guide slot  40  includes a first guide portion  41  which is wider than the minor axis  20  of the guide member  18  but narrower than the major axis  19  of the guide member  18 . The guide slot  40  also includes a second guide portion  42  which is wider than the major axis  19  of the guide member  18 . The guide slot  40  further includes a tapered portion  43  disposed between the first guide portion  41  and the second guide portion  42 . The tapered portion  43  tapers the width of the guide slot  40  between the first guide portion  41  and the second guide portion  42 . 
     In  FIG. 4 , the rotary contact assembly  10  is shown in the first rested state. In the first rested state, the guide member  18  is oriented such that the guide member  18  fits into the first guide portion  41  of the guide slot  40 . When the guide member  18  is in the first guide portion  41  of the guide slot  40 , rotation of the rotary contact assembly  10  is limited due to the width of the first guide portion  41  of the guide slot  40 . In  FIG. 5 , the rotary contact assembly  10  is shown in the partially rotated state. In the partially rotated state, the rotary contact assembly  10  is moved laterally away from the stationary contact  30  and the guide member  18  is moved into the tapered portion  43  or the second guide portion  42  of the guide slot  40 . The rotary contact assembly  10  also rotates, and since the guide member  18  is in the tapered portion  43  or second portion  42  of the guide slot  40 , the guide member  18  is able to rotate. The rotary contact assembly  10  continues to rotate from the partially rotated state to the second rested state shown in  FIG. 6 . In the second rested state of  FIG. 6 , the rotary contact assembly  10  is pressed against the stationary contact  30  and the guide member  18  is disposed in the first guide portion  41  of the guide slot  40 , thus limiting rotation of the rotary contact assembly  10 . 
     The electrical switching apparatus  1  further includes an elastic member  50  (e.g., without limitation, a spring) which biases the rotary contact assembly  10  towards the stationary contact  30 . In the transition between the partially rotated state and the first or second rested states, the elastic member  50  presses the rotary contact assembly  10  to cause it to move back against the stationary contact  30  and to move the guide member  18  back into the first guide portion  41  of the guide slot  40 . In the example embodiment shown in  FIGS. 1-6 , the elastic member  50  is a spring which provides a bias to the rotary contact assembly  10  through a pivot member  51 . However, it is contemplated that any suitable elastic member may be used to provide a bias to the rotary contact assembly  10 . 
     By employing the rotary contact assembly  10 , the electrical switching apparatus  1  is able to couple and uncouple the stationary contact  30  and the rotary contact  13  through uni-directional operation of the solenoid  31 . As such, a uni-directional solenoid can be employed as the solenoid  31 . 
     In one non-limiting example embodiment of the disclosed concept, the electrical switching apparatus  1  is a remote circuit breaker and the stationary contact  30  and rotary contact  13  are the secondary contacts in the remote circuit breaker. A controller (not shown) can control the operation of the solenoid  31  to electrically connect or disconnect the stationary contact  30  and the rotary contact  13 . 
     While specific embodiments of the disclosed concept 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 disclosed concept which is to be given the full breadth of the claims appended and any and all equivalents thereof.