Abstract:
A multi-pole circuit breaker and method include at least two breaker modules including circuit breakers therein. The circuit breakers include a moveable arm configured to connect and disconnect contacts therein. The at least two modules including armatures connectable to the moveable arms of each of the at least two modules. A center module connects the at least two modules. The center module includes an actuator and a beam connected to the actuator at a mid-portion. The beam connects to each armature of the at least two modules wherein under a trip condition the actuator displaces the beam to simultaneously trip the at least two modules using the armatures.

Description:
RELATED APPLICATION INFORMATION 
       [0001]    This application claims priority to provisional application Ser. No. 61/029,595 filed on Feb. 19, 2008, incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    1. Technical Field 
         [0003]    This disclosure relates to circuit breakers, and more particularly, to an apparatus and method for interlocking two or more circuit breaker pole armatures to coordinate breaker tripping events. 
         [0004]    2. Description of the Related Art 
         [0005]    In many multi-pole circuit breaker designs, a crossbar is used to interface with handles associated with each mechanism pole. The crossbar ties the handles together at a pivot point to ensure that all live conductors are interrupted when any pole trips in the multi-pole breaker. This is referred to as a “common trip” breaker, which ties the poles together via their operating handles. 
         [0006]    Without a way to link the breakers together, one armature may trip independently of the other, and the other pole mechanism would then take on more current and thus delay the time to trip. This may cause damage to the circuit of the load for which the circuit breaker was to provide protection. 
       SUMMARY OF THE INVENTION 
       [0007]    A multi-pole circuit breaker and method include at least two breaker modules including circuit breakers therein. The circuit breakers include a moveable arm configured to connect and disconnect contacts therein. The at least two modules include armatures connectable to the moveable arms of each of the at least two modules. A center module connects the at least two modules. The center module includes an actuator and a beam connected to the actuator at a mid-portion. The beam connects to each armature of the at least two modules wherein under a trip condition the actuator displaces the beam to simultaneously trip the at least two modules using the armatures. 
         [0008]    A method for simultaneously tripping a multi-pole circuit breaker includes providing at Least two breaker modules including circuit breakers therein, the circuit breakers including a moveable arm configured to connect and disconnect contacts therein, the at least two modules including armatures connectable to the moveable arms of each of the at least two modules; and a center module connecting the at least two modules, the center module including an actuator, and a beam connected to the actuator at a mid-portion, the beam connecting to each armature of the at least two modules beam. A trip condition is detected in at least one of the at least two breaker modules, and the actuator is energized under the trip condition to displace the beam to simultaneously trip the at least two modules using the armatures. 
         [0009]    These and other objects, features and advantages of the present invention will become apparent from the following detailed description of illustrative embodiments thereof, which is to be read in connection with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0010]    This disclosure will present in detail the following description of preferred embodiments with reference to the following figures wherein: 
           [0011]      FIG. 1  is a perspective view of a multi-pole circuit breaker in accordance with one illustrative embodiment; 
           [0012]      FIG. 2  is a perspective view of the multi-pole circuit breaker of  FIG. 1  with a center module housing removed and one side of a beam for connecting armatures shown disassembled in accordance with one illustrative embodiment; 
           [0013]      FIG. 3  is a perspective view of the multi-pole circuit breaker of  FIG. 2  with the center module housing removed and both sides of the beam for connecting armatures shown disassembled in accordance with one illustrative embodiment; 
           [0014]      FIG. 4  is a perspective view of the multi-pole circuit breaker of  FIG. 1  showing the housings and internal components in phantom and further showing the beam connecting armatures in accordance with one illustrative embodiment; 
           [0015]      FIG. 5  is a perspective view illustratively showing armatures connected to the beam and configured to be displaced by a solenoid in accordance with one illustrative embodiment; 
           [0016]      FIG. 6  is a side view illustratively showing armatures connected to the beam and configured to be displaced by a solenoid in accordance with the illustrative embodiment shown in  FIG. 5 ; and 
           [0017]      FIG. 7  is a side view illustratively showing an armature connected to the beam and configured to release a cradle and thereby trip a breaker in accordance with one illustrative embodiment. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0018]    The present principles provide a mechanical link of armatures of multiple pole current carrying devices. The multiple pole current carrying devices may include residential circuit breaker designs where two outer modules include thermal-magnetic operating mechanisms while a center module includes a magnetic solenoid that mechanically trips the outer poles simultaneously. Where applicable, a direct armature concept is applicable to other designs as well. 
         [0019]    In accordance with the present principles, embodiments are provided to prevent individual poles of multi-pole devices from being tripped independently of one another. This provides a direct interface between the armatures and improves the robustness of multiple pole breaker designs by reducing the number of mechanical interfaces needed. An alternate approach is to employ a separate trip bar which interfaces with the magnetic solenoid with each end supported by outer walls of the breaker. This alternate concept needs tighter control of dimensional clearances/tolerances and may permit too much positional difference between the journals/solenoid/armatures of each pole. 
         [0020]    The present principles are not limited to the illustrative example and may be employed with other circuit breaker types. The functions of the various elements shown in the figures can be provided through the use of dedicated hardware as well as equivalent hardware capable of performing the same or similar functions. Additionally, it is intended that such equivalents include both currently known equivalents as well as equivalents developed in the future (i.e., any elements developed that perform the same function, regardless of structure). 
         [0021]    Referring now in specific detail to the drawings in which like reference numerals identify similar or identical elements throughout the several views, and initially to  FIG. 1 , a multi-pole circuit breaker  10  is illustratively shown. Circuit breaker  10  includes three modules. Outer modules  100  and  104  include similar mechanisms configured to trip under current surges or overload currents. These components may include fixed contacts, moveable contacts, moveable arms or poles which cause a breaker in a circuit between the fixed and moveable contacts and any other mechanical or electrical components which may be employed in a circuit breaker. Since such components may vary and may be known, further description is omitted for simplicity. 
         [0022]    Circuit breaker  10  includes a center module  102  that includes electronics or electrical components employed in tripping the circuit breaker  10  during operation. The outer modules  100  and  104  include handles  106  employed in manually tripping the breaker  10  or resetting the breaker  10  after a trip. Since the breaker  10  is a multi-pole breaker, two handles  106  are shown. It should be understood that any number of modules  100  or  104  may be employed and may be configured in accordance with the present principles to trip simultaneously. A coil of wire  108  is shown for connecting the breaker  10  during installation. 
         [0023]    Referring to  FIGS. 2 and 3 , a three modular type assembly is shown, with the outer modules  100  and  104  including thermal and magnetic operating mechanisms. A housing for the center module  102  is removed to show a magnetic solenoid  122  that will mechanically trip poles of the outer module  100  and  104  simultaneously. This is accomplished by a solenoid beam  124 , attached directly to the solenoid  122  in the center module  102 . Ends  126  of the beam  124  extend into the outer poles and attach to armatures (not shown). 
         [0024]      FIG. 2  shows one end  126  assembled into module  104  and the other end  126  separated from module  100 . In  FIG. 3 , the solenoid  122 , beam  124  and board  128  are shown detached. 
         [0025]    In one illustrative embodiment, the solenoid beam  124  of the center module  102  with electronics board  128  is press fit onto the solenoid  122 , and then press fit into armatures (not shown) in each outer pole  100  and  104  thus linking the armatures together. Other attachment types may also be employed. In this design, there is illustratively only one magnetically latching solenoid  122  for both armatures located in the outer modules  100  and  104 . Two or more solenoids  122  may be employed as well. The solenoid  122  is located in the center pole module  102  that is sandwiched between the two outer modules  100  and  104 . The solenoid beam  124  is used in the center compartment and is attached directly to the solenoid  122 . 
         [0026]    Referring to  FIG. 4 , a perspective view of breaker  10  is rendered transparent to permit visualization of armatures  130  within modules  100  and  104 . The beam  124  prevents tilt between the armatures  130 , and the beam  124  is linked to the armatures  130  included in the outer poles  100  and  104  preferably by a press fit. An end  132  of the “ 2 ” or “Z” shaped rods serves as a wrist pin that ties outer pole solenoids, if present, and connects to a bimetal or magnetic yoke assembly ( FIG. 7 ). The solenoid  122  of the center module  102  is linked to the solenoid beam  124  preferably by a press fit. Since the solenoid  122  and the armatures  130  in the outer poles or modules  100  and  104  are all linked together, all poles ( 100  and  1041  are tripped simultaneously. 
         [0027]    Another advantage of the configuration of breaker  10  is that it eliminates the need for a second magnetically latching solenoid since the center pole or module  102  employs the solenoid beam  124 . The breaker configuration also eliminates the need for a separate trip bar. 
         [0028]    Referring to  FIG. 5 , armatures  130  are illustratively shown connected by beam  124 , where the beam passes through the board  128 . The solenoid  122  is powered or energized and controlled through the board  128  which is preferably a printed wiring board or PCB. An opening  140  in the board  128  for the beam  124  is small in size since the PCB  128  will only need to provide a small opening for the beam  124  to travel. 
         [0029]    Referring to  FIG. 6 , a side view of the solenoid  122  and the armatures  130  is illustratively shown. The outer modules  100  and  104  include the thermal and magnetic operating mechanisms while the center compartment  102  ( FIG. 1 ) includes the magnetic solenoid  122  that will mechanically trip armatures  130  of the outer poles simultaneously. The solenoid beam  124  is attached directly to the solenoid  122 , where each end of the beam  124  extends into the outer poles and attaches to the armatures  130 . 
         [0030]    Referring to  FIG. 7 , a diagram showing the interaction between a moveable blade or moveable arm  202  of outer modules  100  and  104  and an armature  130  is illustratively depicted. The solenoid  122  ( FIG. 63  is activated by electronic circuitry. Each mechanical pole can be tripped with a bimetal  204  or a magnetic construction  206 , which handle surges and overload conditions in outer modules  100  and  104 . Residential circuit breakers are typically designed with a bimetal  204  and magnetic yoke assembly  206  to mechanically detect when an overload or instantaneous condition exists. When either of these conditions exists, armature  130  is rotated by the bending of the bimetal  204  or by the magnetic force generated by the yoke assembly  206 . As the armature  130  rotates, the mechanism pole de-latches and trips the mechanism, thus opening a circuit. 
         [0031]    In the illustrative embodiment shown, electronics in the outer modules  100  and  104  monitor the current going through each pole. The solenoid  122  ( FIG. 6 ) is activated when one pole no longer has current or when an arc fault has been detected on either pole. Once the solenoid  122  has been triggered, the solenoid  122  rotates the beam  124  that is connected to both armatures  130  (See  FIG. 5 ). This permits a notch  210  on armature  130  to move away from a cradle  212 . The cradle  212  rotates passed notch  210  (in the direction of arrow “A”). This, in turn, causes the moveable blade  202  to trip and move away from a stationary or fixed contact  216  in the direction of arrow “B” to cause an open circuit. Since the outer modules  100  and  104  employ armatures  130  and beam  124 , this ensures that both mechanical poles have been tripped together. 
         [0032]    Having described preferred embodiments for multi-pole armature interlock for circuit breakers which are intended to be illustrative and not limiting), it is noted that modifications and variations can be made by persons skilled in the art in light of the above teachings. It is therefore to be understood that changes may be made in the particular embodiments of the invention disclosed which are within the scope and spirit of the invention as outlined by the appended claims. Having thus described the invention with the details and particularity required by the patent laws, what is claimed and desired protected by Letters Patent is set forth in the appended claims.