Patent Publication Number: US-9892881-B2

Title: Circuit breaker alarm module accessible for manual testing

Description:
FIELD 
     The present invention relates generally to accessories for circuit breakers, such as short circuit indicating alarm modules. 
     BACKGROUND 
     In general, a circuit breaker operates to engage and disengage a selected branch electrical circuit from an electrical power supply. The circuit breaker provides current interruption thereby providing protection to the electrical circuit from continuous over-current conditions and/or high-current transients due, for example. Such circuit breakers operate by separating internal electrical contacts contained within a housing of the circuit breaker. 
     In some embodiments, the circuit breakers include a thermal-magnetic trip unit wherein the contact arms blow apart from the stationary contacts due to magnetic forces or as a result of thermal heating of a bimetal element. In such thermal-magnetic circuit breakers, an accessory pocket may be provided that includes a magnetic trip bar that rotates in response to a short circuit that trips the circuit breaker and disconnects the electrical contacts. Certain thermal-magnetic circuit breakers may include a short circuit indicating accessory module in the accessory pocket. Furthermore, certain thermal-magnetic circuit breakers may include an internal trip switch that is activated by rotation of the trip bar to send an electrical signal to a location indicating the circuit breaker has been tripped. The short circuit indicating accessory module may mechanically and visually indicate that a short circuit trip has occurred by either sounding an alarm or providing a visual indicator. 
     However, such thermal-magnetic circuit breakers including short circuit indicating accessory modules may be deficient in some respects. Thus, improved short circuit indicating accessory module and assemblies including them are desired. 
     SUMMARY 
     According to a first aspect, a short circuit indicating alarm module is provided. The short circuit indicating alarm module includes a housing, a latch pivotally mounted relative the housing, the latch including a latching member configured to be contacted by a catch of a trip bar, and a plunger translatable relative to the housing and configured, upon depressing, to contact and trip the trip bar. 
     In accordance with another aspect, a trip indicator assembly is provided. The trip indicator assembly includes a trip bar including a catch and a trip contact surface, and a short circuit indicating alarm module, including a housing, a latch pivotally mounted relative the housing, the latch including a latching member configured to be contacted by the catch of the trip bar, and a plunger translatable relative to the housing and configured, upon depressing, to contact the trip contact surface of the trip bar. 
     In accordance with another aspect, a modular assembly of a circuit breaker including a short circuit indicating accessory module is provided. The modular assembly includes a base housing including an accessory pocket, a trip bar mounted for rotation in the base housing about a pivot axis, the trip bar including a first contact area configured to be contacted by a mechanism of the circuit breaker, a catch offset from the pivot axis, and a trip contact surface, and a short circuit indicating alarm module received in the accessory pocket, comprising a housing, a latch pivotally mounted relative the housing, the latch including a latching member configured to be contacted by the catch of the trip bar, and a plunger moveable relative to the housing and configured, upon depressing, to contact the trip contact surface to trip the trip bar as a test. 
     In accordance with another aspect, a method of testing a short circuit indicating alarm module of a circuit breaker is provided. The method includes providing a trip bar including a catch and a trip contact surface, providing the short circuit indicating alarm module including a housing, a latch pivotally mounted relative the housing, the latch including a latching member configured to be contacted by the catch of the trip bar, and a plunger moveable relative to the housing, and depressing the plunger and contacting the trip contact surface of the trip bar to trip the trip bar as a test. 
     Still other aspects, features, and advantages of the present invention may be readily apparent from the following description by illustrating a number of example embodiments, including the best mode contemplated for carrying out the present invention. The present invention may also be capable of different embodiments, and its details may be modified in various respects, all without departing from the scope of the present invention. Accordingly, the drawings and descriptions are to be regarded as illustrative in nature, and not as restrictive. The invention is to cover all modifications, equivalents, and alternatives falling within the scope of the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The drawings, described below, are for illustrative purposes only and are not necessarily drawn to scale. Like reference numerals used in the drawings identify similar or identical elements throughout the several views. The drawings are not intended to limit the scope of the invention in any way. 
         FIG. 1A  illustrates a side plan view of a trip indicator assembly including a short circuit indicating alarm module with the right side case removed for illustration purposes, wherein the short circuit indicating alarm module is shown in a non-tripped condition according to one or more embodiments. 
         FIG. 1B  illustrates a side plan view of a trip indicator assembly including a short circuit indicating alarm module with the right side case removed for illustration purposes, wherein the short circuit indicating alarm module is shown in a tripped condition, according to one or more embodiments. 
         FIG. 1C  illustrates an isometric view of a modular assembly including a short circuit indicating alarm module with the right side case removed for illustration purposes, and shown in a non-tripped condition, according to one or more embodiments. 
         FIG. 1D  illustrates an isometric view of a modular assembly including a short circuit indicating alarm module with the right side casing removed for illustration purposes, and shown in a tripped condition, according to one or more embodiments. 
         FIGS. 1E and 1F  illustrate isometric views of an internal support of a base housing according to one or more embodiments. 
         FIG. 2  illustrates an isometric view of a latch of the short circuit indicating alarm module according to one or more embodiments. 
         FIG. 3  illustrates an isometric view of a slider member of a short circuit indicating alarm module according to one or more embodiments. 
         FIG. 4  illustrates an isometric view of a plunger of a short circuit indicating alarm module according to one or more embodiments. 
         FIG. 5A  illustrates an isometric view of a left side case of a housing of a short circuit indicating alarm module according to one or more embodiments. 
         FIG. 5B  illustrates an isometric view of a right side case of a housing of a short circuit indicating alarm module according to one or more embodiments. 
         FIGS. 6A and 6B  illustrate first and second side isometric views of a trip bar according to one or more embodiments. 
         FIG. 7A  illustrates a top isometric view of a thermal-magnetic circuit breaker including a short circuit indicating alarm module according to one or more embodiments. 
         FIGS. 7B and 7C  illustrate partial top isometric views of interactive components (e.g., plunger and trip indicator flag) of a short circuit indicating alarm module according to one or more embodiments. 
         FIG. 8  illustrates a flowchart of a method of operating a short circuit indicating alarm module according to one or more embodiments. 
     
    
    
     DESCRIPTION 
     Reference will now be made in detail to the example embodiments of this disclosure, which are illustrated in the accompanying drawings. 
     In order to ensure that an accessory module is fully functional, embodiments of the invention provide test functionality to the accessory module, so that the operability of the accessory module and possibly other components may be tested without having to apply high current levels to the circuit breaker. This avoids degradation of the electrical contacts of the circuit breaker with which the accessory module operates. In one or more embodiments, a short circuit indicating accessory module is provided. The short circuit indicating accessory module, in operation, indicates that a magnetic trip event has occurred, and a test plunger is provided, which when depressed by an operator, engages with and moves (e.g., rotates) a trip bar. This allows the operator to trip the circuit breaker to test the short circuit indicating accessory module and also any other switching component without applying a current to the circuit breaker. Once tripped, the short circuit indicating accessory module provides reset capability wherein an operator can reset the short circuit indicating accessory module upon depressing a slider member. Once the slider member is reset, thereby releasing the trip bar and allowing the trip bar to return to a normal position, then the circuit breaker handle can be returned to the ON position. 
     One or more embodiments of the invention are directed at a short circuit indicating alarm module including a housing, a latch pivotally mounted in the housing, the latch including a latching member that is configured to be contacted by a catch of a trip bar, and a plunger that is translatable relative to the housing and configured, upon depressing, to contact and trip the trip bar as a test. 
     In other embodiments, a trip indicating assembly for use with a circuit breaker is provided. The trip indicating assembly includes the short circuit indicating alarm module and a trip bar. 
     One or more embodiments of the invention may be used with one-pole or two-pole thermal-magnetic circuit breakers. Such thermal-magnetic circuit breakers may include ratings of between about 100 Amp to 2000 Amp (including ratings of 100 Amp, 250 A Amp, 600 Amp, 1000 Amp, 1200 Amp, and 2000 Amp), for example. 
     These and other embodiments of short circuit indicating alarm module, trip indicator assemblies for circuit breakers, modular assemblies for circuit breakers including short circuit indicating alarm module, as well as methods of testing a short circuit indicating alarm module are described below with reference to  FIGS. 1A-8  herein. 
     Referring now to  FIGS. 1A-1D , a trip indicating assembly  100  including a short circuit indicating alarm module  102  is provided in accordance with one or more embodiments of the invention. Trip indicating assembly  100  includes the short circuit indicating alarm module  102  and a trip bar  104 . 
     In more detail, the short circuit indicating alarm module  102  includes a housing  106 , and a latch  108  pivotally mounted relative the housing  106 . Further, the latch  108  includes a latching member  110  configured to be contacted by a catch  112  of the trip bar  104  as the trip bar  104  rotates. 
     Additionally, the short circuit indicating alarm module  102  includes a plunger  114  that is translatable and reciprocatable relative to the housing  106  and configured, upon an operator depressing the upper end  116  thereof, to contact and manually trip the trip bar  104  and thereby trip the circuit breaker. Short circuit indicating alarm module  102  may further include a slider member  107  to be described fully below. 
     Trip indicating assembly  100  includes the trip bar  104  with the catch  112  as previously discussed, and further includes a trip contact surface  124 , which is configured to be engageable by an engaging end  115  of the plunger  114 . Trip contact surface  124  may be arranged along a side of the catch  112 , and may be an inclined surface. The trip contact surface  124  may be inclined. For example, trip contact surface  124  may be inclined at an incline angle  127  of between about 25 degrees and about 50 degrees, as measured between an inclined plane of the trip contact surface  124  and an axial axis  117  of the plunger  114 . The plunger  114  is translatable relative to the housing  106  along the axial axis and is configured, upon being depressing by an operator (e.g., by depressing with a user&#39;s finger  119 ), to contact the trip contact surface  124  of the trip bar  104 . This causes the trip bar  104  to rotate about trip bar axle  121 , as shown in  FIG. 1B . As a result, the circuit breaker may be tripped, but also, a switch arm  123  may be rotated, which may activate a trip switch  129  that may send a signal in signal line  131  that the circuit breaker has been magnetically tripped. Trip switch  129  may be an internal switch of the circuit breaker. 
     As can be seen in  FIG. 1B , once the circuit breaker has been tripped, the latching member  110  on the latch  108  engages the catch  112  of the trip bar  104  and holds the trip bar  104  in the tripped position, as shown. The trip bar  104  may be returned to the ON position after the operator moves the slider member  107  to rotate and release the latch  108 . This raises the latching member  110  and allows the trip bar  104  to return to a non-tripped condition as shown in  FIG. 1A , then the circuit breaker can be reset and the breaker handle can be returned to the ON position. The slider member  107  may be moved by contacting the end of the trip indicating flag  136  with a tool, such as a flat-head screwdriver, for example. 
       FIGS. 1C and 1D  illustrate isometric views of a modular assembly  141  adapted to couple to a circuit breaker (e.g., thermal-magnetic circuit breaker  700  shown in  FIG. 7A ). Modular assembly  141  includes the trip indicating assembly  100 , which includes the short circuit indicating alarm module  102  and trip bar  104  housed within a base housing  143 . The base housing  143  includes a mounting base  145  and an internal support  147  ( FIGS. 1E-1F ) that may be configured to be coupled to the mounting base  145 . Together, the mounting base  145  and the internal support  147  provide support and rotation surfaces for the trip bar  104  to rotate in, and an accessory pocket  149  configured to receive the short circuit indicating alarm module  102 . 
     Also shown in  FIGS. 1C and 1D , is a thermal trip bar  151 , which may share a common axle with the trip bar  104 . Trip bar  104  and thermal trip bar  151  are mounted in the mounting base  145  and are secured in place by the internal support  147 . 
     Referring now to  FIG. 2 , an isometric view of the latch  108  is shown. Latch  108  may include a latch body  226  and includes the latching member  110 . The latching member  110  may extend in a first direction from the latch body  226 . A trigger member  228  may extend in a second direction from the latch body  226  and may be moveable responsive to pivotal movement of the latch caused by contact between the latching member  110  and the catch  112 . Trigger member  228  interacts with a release member  332  of a slider member  107  (see  FIG. 3 ). Latch  108  may further include bearing pins  238  on a same relative location on either side of the latch  108  (only one shown) to provide a pivot axle  240  for the latch  108  to pivot around. Bearing pins  238  may be received in bores  553  formed in the first and second side cases  106 A,  106 B (see  FIGS. 5A and 5B ). Latch  108  may include a latch spring retainer  254  configured to interface with the latch spring  155  ( FIGS. 1A and 1B ). Latch  108  may be formed of a molded polymer material, such as Nylon, for example. Other suitably rigid materials may be used. 
     Referring now to  FIGS. 1A, 1B and 3 , the slider member  107  is shown. Slider member  107  may include the release member  332 , which is configured to engage with a trigger member  228  of the latch  108 , a guide  334  configured to be received in a like-shaped feature formed from one or more cavities  537 A,  537 B formed in sidewalls in the first and second side cases  106 A,  106 B, and a trip indicating flag  136 . Trip indicating flag  136  provides a visual indication that the circuit breaker (e.g., thermal-magnetic circuit breaker  700  shown in  FIG. 7 ) has been tripped. Slider member  107  may be made from a rigid material, such as polycarbonate or nylon. Slider member  107  may be configured to translate upon tripping, wherein the trip indicating flag  136  is extended into a view window  158 . View window  158  may be provided by a recess  539  (See  FIGS. 5A-5B ) of the housing  106 . Slider member  107  may be spring biased to an extended condition when released from the latch  108  to move the trip indicating flag  136  into the view window  158 . Spring bias may be provided by slider spring  150 , which may register on slider spring retainer  159 . Slider spring  150  may be a coil spring, for example. Other types of springs may be used. 
     Referring to  FIG. 4 , the plunger  114  may include a plunger body  442  and the shaft  122  extending from a bottom side of the plunger body  442 , as shown. The plunger body  442  may include one or more stops  444 A,  444 B that may be received against a top surface (e.g., top inside surface  157 ) of the housing  106  to limit extension of the plunger  114 . This limit of extension may position the upper end  116  of the plunger  114  at a position that is approximately even with an upper surface of the housing  106 . The upper end  116  may be manually depressed by the operator to test the operability of the short circuit indicating alarm module  102  and any other accessory (e.g., a trip switch activated by the switch arm  123 ). As is shown in  FIGS. 1A and 1B , a plunger spring  148  may be used to bias the plunger  114  to a top inside surface  157  of the housing  106 . Furthermore, the shaft  122  of the plunger  114  may extend out of a bottom surface of the housing  106  to engage with the trip contact surface  124  of the trip bar  104 . 
     As shown in  FIGS. 5A and 5B , the housing  106  may be made up of the first and second side cases  106 A,  106 B. First and second side cases  106 A,  106 B may be made from a suitable plastic material, for example. The material may be a thermoset material, such as a glass-filled polyester, or a thermoplastic material such as a Nylon material (e.g., Nylon 6), for example. Other suitable insulating materials may be used. 
     The first and second side cases  106 A,  106 B may be connected together to form the housing  106 . Housing  106  may include an upper aperture  518  configured to receive the upper end  116  of the plunger  114 . Housing  106  may include a lower aperture  520  configured to receive a shaft  122  of the plunger  114 . Housing  106  may include a recess that comprises a view window  158  that receives the trip indicating flag  136  therein. Housing  106  may include the bores  553  in the first and second side cases  106 A,  106 B that may be configured to receive bearing pins  238  of the latch  108 . 
     As shown in  FIGS. 1A-1B and 6A-6B , the trip bar  104  includes a first end including the catch  112  and the trip contact surface  124 , which are offset from the pivot axis  660 . A magnetic interface portion  668  is operable with an armature and yoke assembly of the circuit breaker  700  to cause tripping of the trip bar  104  due to short circuits. Additional feature  665  may interface with the thermal trip bar  151 . 
     As shown in  FIG. 7A , a thermo-magnetic, three-pole embodiment of a circuit breaker  700  is depicted including the short circuit indicating alarm module  102  in an accessory pocket  149  thereof. Circuit breaker  700  may be rated between 100 Amp and 2,000 Amp, for example. The accessory cover is shown removed, but would be re-installed with a window knocked out to allow physical access to the plunger  114  and visual access to the trip indicating flag  136 .  FIGS. 7B and 7C  illustrate enlarged partial views of the view window  158  of the short circuit indicating alarm module  102  shown in an ON condition ( FIG. 7B ) and tripped condition ( FIG. 7C ). 
     According to another aspect, a method of testing a short circuit indicating alarm module is provided. As shown in  FIG. 8 , the method  800  includes, in  802 , providing a trip bar (e.g., trip bar  104 ) including a catch (e.g., catch  112 ) and a trip contact surface (e.g., trip contact surface  124 ). 
     The method  800  includes, in  804 , providing the short circuit indicating alarm module (e.g., short circuit indicating alarm module  102 ) including a housing (e.g., housing  106 ), a latch (e.g., latch  108 ) pivotally mounted relative the housing, the latch including a latching member (e.g., latching member  110 ) configured to be contacted by the catch (e.g., catch  112 ) of the trip bar (e.g., trip bar  104 ), and a plunger (e.g., plunger  114 ) moveable relative to the housing. 
     The method  800  includes, in  806 , depressing the plunger (e.g., plunger  114 ) and contacting the trip contact surface (e.g., trip contact surface  124 ) of the trip bar (e.g., trip bar  104 ) to trip the trip bar as a test. Thus, the functionality of the short circuit indicating alarm module  102  may be tested without having to pass current through the circuit breaker (e.g., circuit breaker  600 ). Further, functionality of other accessories, such as a trip switch  129 , may be tested. Thus, testing time and cost may be reduced, as well as wear on the electrical contacts of the circuit breaker  700 . 
     While the invention is susceptible to various modifications and alternative forms, specific embodiments and methods thereof have been shown by way of example in the drawings and are described in detail herein. It should be understood, however, that it is not intended to limit the invention to the particular apparatus, assemblies, or methods disclosed herein, but to the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the scope of the appended claims.