Patent Publication Number: US-2022238288-A1

Title: Switchgear with manual trip assembly and mechanical interlock

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to co-pending U.S. Provisional Patent Application No. 62/839,278, filed on Apr. 26, 2019, and to co-pending U.S. Provisional Patent Application No. 62/902,637, filed on Sep. 19, 2019, the entire contents of both of which are incorporated herein by reference. 
    
    
     FIELD OF THE DISCLOSURE 
     The present disclosure relates to solid dielectric switchgear, and more particularly to reclosers. 
     BACKGROUND OF THE DISCLOSURE 
     Reclosers are switchgear that provide line protection, for example, on overhead electrical power lines and/or substations and serve to segment the circuits into smaller sections, reducing the number of potentially impacted customers in the event of a short circuit. Previously, reclosers were controlled using hydraulics. More recently, solid dielectric reclosers have been developed for use at voltages up to 38 kV. Solid dielectric reclosers may be paired with electronic control devices to provide automation and “smart” recloser functionality. 
     SUMMARY OF THE DISCLOSURE 
     A need exists for fault protection and circuit segmentation in power transmission circuits, which typically operate at higher voltages (e.g., up to 1,100 kV). Reclosers allow for multiple automated attempts to clear temporary faults on overhead lines. A need also exists, however, for a recloser with a manual trip assembly that allows the recloser to be manually operated for servicing or in the event of a failure of the recloser or its controls. 
     The present disclosure provides, in one aspect, a switchgear apparatus configured for operation at voltages up to 72.5 kV, including a vacuum interrupter assembly having a fixed contact and a movable contact configured to move relative to the fixed contact between a closed position in which the movable contact is in contact with the fixed contact and an open position in which the movable contact is spaced from the fixed contact. The switchgear apparatus also includes an electromagnetic actuator configured to move the movable contact between the open position and the closed position, a manual trip assembly movable from an initial position to an actuated position to move the movable contact from the closed position to the open position, and a mechanical interlock assembly configured to prevent the movable contact from moving from the open position to the closed position when the manual trip assembly is in the actuated position. 
     The present disclosure provides, in another aspect, a switchgear apparatus configured for operation at voltages up to 72.5 kV, including a vacuum interrupter assembly having a fixed contact and a movable contact configured to move relative to the fixed contact between a closed position in which the movable contact is in contact with the fixed contact and an open position in which the movable contact is spaced from the fixed contact. The switchgear apparatus also includes an electromagnetic actuator configured to move the movable contact between the open position and the closed position, and a manual trip assembly movable from an initial position to an actuated position to move the movable contact from the closed position to the open position. The manual trip assembly includes a first lever and a second lever coupled to the first lever such that the first and second lever provide a compound mechanical advantage. 
     Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a recloser and/or switchgear apparatus (“recloser”) according to an embodiment of the present disclosure. 
         FIG. 2  is a cross-sectional view of the recloser of  FIG. 1 . 
         FIG. 3  is an exploded perspective view of a housing of the recloser of  FIG. 1 . 
         FIG. 4  is a perspective view of a head casting of the recloser of  FIG. 1 . 
         FIG. 5  is a cross-sectional view of the recloser of  FIG. 1 , taken through the head casting of  FIG. 4 . 
         FIG. 6  is a perspective view illustrating a manual trip assembly of the recloser of FIG. 
         FIG. 7  is a cross-sectional view illustrating a portion of the manual trip assembly of  FIG. 6  in an initial position. 
         FIG. 8  is a cross-sectional view illustrating a portion of the manual trip assembly of  FIG. 6  in an intermediate position. 
         FIG. 9  is a cross-sectional view illustrating a portion of the manual trip assembly of  FIG. 6  in an actuated state. 
         FIG. 10  is a side view illustrating actuation of the manual trip assembly. 
     
    
    
     DETAILED DESCRIPTION 
     Before any embodiments of the disclosure are explained in detail, it is to be understood that the disclosure is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The disclosure is capable of supporting other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. In addition, as used herein and in the appended claims, the terms “upper”, “lower”, “top”, “bottom”, “front”, “back”, and other directional terms are not intended to require any particular orientation, but are instead used for purposes of description only. 
       FIG. 1  illustrates a recloser  10  according to an embodiment of the present disclosure. The recloser  10  includes a housing assembly  14 , a vacuum interrupter (“VI”) assembly  18 , a conductor assembly  22 , which in some embodiments may be a load-side conductor assembly  22  and in other embodiments may be a source-side conductor assembly  22 , and an actuator assembly  26 . The VI assembly  18  includes a first terminal  30  extending from the housing assembly  14  along a first longitudinal axis  34 , and the conductor assembly  22  includes a second terminal  38  extending from the housing assembly  14  along a second longitudinal axis  42  perpendicular to the first longitudinal axis  34 . In other embodiments, the second longitudinal axis  42  may be obliquely oriented relative to the first longitudinal axis  34 . The actuator assembly  26  may operate the VI assembly  18  to selectively break and/or reestablish a conductive pathway between the first and second terminals  30 ,  38 . Although the recloser  10  is illustrated individually in  FIG. 1 , the recloser  10  may be part of a recloser system including a plurality of reclosers  10 , each associated with a different phase of a three-phase power transmission system and ganged together such that operation of the plurality of reclosers  10  is synchronized. 
     Referring now to  FIG. 2 , the illustrated housing assembly  14  includes a main housing  46  with an insulating material, such as epoxy, that forms a solid dielectric module  47 . The solid dielectric module  47  is preferably made of a silicone or cycloaliphatic epoxy. In other embodiments, the solid dielectric module  47  may be made of a fiberglass molding compound. In other embodiments, the solid dielectric module  47  may be made of other moldable dielectric materials. The main housing  46  may further include a protective layer  48  surrounding the solid dielectric module  47 . In some embodiments, the protective layer  48  withstands heavily polluted environments and serves as an additional dielectric material for the recloser  10 . In some embodiments, the protective layer  48  is made of silicone rubber that is overmolded onto the solid dielectric module  47 . In other embodiments, the protective layer  48  may be made of other moldable (and preferably resilient) dielectric materials, such as polyurethane. 
     With continued reference to  FIG. 2 , the main housing  46  includes a first bushing  50  that surrounds and at least partially encapsulates the VI assembly  18 , and a second bushing  54  that surrounds and at least partially encapsulates the conductor assembly  22 . The silicone rubber layer  48  includes a plurality of sheds  58  extending radially outward from both bushings  50 ,  54 . In other embodiments, the sheds  58  may be formed as part of the dielectric module  47  and covered by the silicone rubber layer  48 . In yet other embodiments, the sheds  58  may be omitted. The first and second bushings  50 ,  54  may be integrally formed together with the dielectric module  47  of the main housing  46  as a single monolithic structure. Alternatively, the first and second bushings  50 ,  54  may be formed separately and coupled to the main housing  46  in a variety of ways (e.g., via a threaded connection, snap-fit, etc.). 
     The illustrated VI assembly  18  includes a vacuum bottle  62  at least partially molded within the first bushing  50  of the main housing  46 . The vacuum bottle  62  encloses a movable contact  66  and a stationary contact  70  such that the movable contact  66  and the stationary contact  70  are hermetically sealed within the vacuum bottle  62 . In some embodiments, the vacuum bottle  62  has an internal absolute pressure of about 1 millipascal or less. The movable contact  66  is movable along the first longitudinal axis  34  between a closed position (illustrated in  FIG. 2 ) and an open position (not shown) to selectively establish or break contact with the stationary contact  70 . The vacuum bottle  62  quickly suppresses electrical arcing that may occur when the contacts  66 ,  70  are opened due to the lack of conductive atmosphere within the bottle  62 . 
     The conductor assembly  22  may include a conductor  74  and a sensor assembly  78 , each at least partially molded within the second bushing  54  of the main housing  46 . The sensor assembly  78  may include a current sensor, voltage sensor, partial discharge sensor, voltage indicated sensor, and/or other sensing devices. One end of the conductor  74  is electrically coupled to the movable contact  66  via a current interchange  82 . The opposite end of the conductor  74  is electrically coupled to the second terminal  38 . The first terminal  30  is electrically coupled to the stationary contact  70 . The first terminal  30  and the second terminal  38  are configured for connection to respective electrical power transmission lines. 
     With continued reference to  FIG. 2 , the actuator assembly  26  includes a drive shaft  86  extending through the main housing  46  and coupled at one end to the movable contact  66  of the VI assembly  18 . In the illustrated embodiment, the drive shaft  86  is coupled to the movable contact  66  via an encapsulated spring  90  to permit limited relative movement between the drive shaft  86  and the movable contact  66 . The encapsulated spring  90  biases the movable contact  66  toward the stationary contact  70 . The opposite end of the drive shaft  86  is coupled to an output shaft  94  of an electromagnetic actuator  98 . The electromagnetic actuator  98  is operable to move the drive shaft  86  along the first longitudinal axis  34  and thereby move the movable contact  66  relative to the stationary contact  70 . In additional or alternative embodiments, the functionality provided by the encapsulated spring  90  may be provided with an external spring and/or a spring positioned otherwise along the drive shaft  86 . For example, the spring may be instead positioned at a first end or at a second end of the drive shaft  86 . 
     The electromagnetic actuator  98  in the illustrated embodiment includes a coil  99 , a permanent magnet  100 , a spring  101 , and a plunger  103  that is coupled to the output shaft  94 . The coil  99  includes one or more copper windings which, when energized, produce a magnetic field that acts on the plunger  103  to move the output shaft  94 . The permanent magnet  100  is configured to hold the plunger  103  and the output shaft  94  in a position corresponding with the closed position of the movable contact  66 . In some embodiments, the permanent magnet  100  may produce a magnetic holding force on the output shaft  94  of about 10,000 Newtons (N). In other embodiments, the permanent magnet  100  may produce a magnetic holding force on the output shaft  94  between 7,000 N and 13,000 N. 
     The spring  101  biases the output shaft  94  in an opening direction (i.e. downward in the orientation of  FIG. 2 ) to facilitate opening the contacts  66 ,  70 , as described in greater detail below. The force exerted by the spring  101  when the contacts  66 ,  70  are in the closed position is less than the magnetic holding force. For example, in some embodiments, the force exerted by the spring  101  when the contacts  66 ,  70  are in the closed position may be about 5,000 N. In other embodiments, the force may be between 2,000 N and 6,000 N. Thus, the permanent magnet  100  provides a strong magnetic holding force to maintain the contacts  66 ,  70  in their closed position against the biasing force of the spring  101 , without requiring any current to be supplied through the coil  99 . 
     In some embodiments, the actuator assembly  26  may include other actuator configurations. For example, in some embodiments, the permanent magnet  100  may be omitted, and the output shaft  94  may be latched in the closed position in other ways. In additional or alternative embodiments, the electromagnetic actuator  98  may be omitted or replaced by any other suitable actuator (e.g., a hydraulic actuator, etc.). 
     The actuator assembly  26  includes a controller (not shown) that controls operation of the electromagnetic actuator  98 . In some embodiments, the controller receives feedback from the sensor assembly  78  and energizes and/or de-energizes the electromagnetic actuator  98  automatically in response to one or more sensed conditions. For example, the controller may receive feedback from the sensor assembly  78  indicating that a fault has occurred. In response, the controller may control the electromagnetic actuator  98  to automatically open the VI assembly  18  and break the circuit. The controller may also control the electromagnetic actuator  98  to automatically close the VI assembly  18  once the fault has been cleared (e.g., as indicated by the sensor assembly  78 ). 
     The illustrated housing assembly  14  includes an actuator housing  114  enclosing the electromagnetic actuator  98  and a head casting  118  coupled between the actuator housing  114  and the main housing  46 . In the illustrated embodiment, the head casting  118  supports a connector  138  in communication with the sensor assembly  78  such that feedback from the sensor assembly  78  may be obtained by interfacing with the connector  138  ( FIG. 3 ). The head casting  118  is coupled to the main housing  46  by a first plurality of threaded fasteners  122 , and the actuator housing  114  is coupled to the head casting  118  opposite the main housing  46  by a second plurality of threaded fasteners  126 . 
     Referring to  FIGS. 4 and 5 , the head casting  118  includes a main body  126  and a plurality of mounting bosses  130  spaced along the outer periphery of the main body  126 . In the illustrated embodiment, the plurality of mounting bosses  130  includes a first pair of bosses  130   a  extending from the main body  126  in a first direction, a second pair of bosses  130   b  extending from the main body  126  in a second direction opposite the first direction, and a third pair of bosses  130   c  extending from the main body  126  in a third direction orthogonal to the first and second directions. In other embodiments, the head casting  118  may include a different number and/or arrangement of mounting bosses  130 . 
     The head casting  118  is couplable to the main housing  46  in a plurality of different orientations such that the pairs of bosses  130  ( 130   a,    130   b,    130   c ) may be positioned in a number of different rotational orientations about axis  34  with respect to the main housing  46 . That is, the rotational orientation of the pairs of bosses  130  about the circumference of the main housing  46  may be varied as desired by rotating the orientation of the head casting  118  and main housing  46  relative to one another about the axis  34  to a desired position before coupling the head casting  118  and the main housing  46 . In some embodiments, the head casting  118  may be coupled to the main housing  46  in at least three different orientations. In other embodiments, the head casting  118  may be coupled to the main housing  46  in at least six different orientations. In other embodiments, the main housing  46 , the head casting  118 , and the actuator housing  114  may be coupled together in other ways (e.g., via direct threaded connections or the like). 
     With reference to  FIG. 5 , the illustrated actuator assembly  26  includes a manual trip assembly  102  supported by the head casting  118  and that can be used to manually open the VI assembly  18 . The manual trip assembly  102  includes a handle  104  accessible from an exterior of the housing assembly  14 . In the illustrated embodiment, the handle  104  of the manual trip assembly  102  extends along a side of the main body  126  opposite the third pair of bosses  130   c  and generally adjacent the connector  138 . The handle  104  is preferably at a grounded potential. Because the head casting  118  is couplable to the main housing  46  in different orientations, the position of the handle  104  with respect to the main housing  46  is also variable. As such, the handle  104  may be accessible to an operator when the recloser  10  is in a wide variety of different mounting configurations. As described in greater detail below, the handle  104  is rotatable about a first rotational axis  105  to move a yoke  106  inside the head casting  118 . The yoke  106  is engageable with a collar  110  on the output shaft  94  to move the movable contact  66  ( FIG. 2 ) toward the open position. 
     Referring to  FIGS. 5-6 , the illustrated manual trip assembly  102  includes a pair of support brackets  133  fixed inside the head casting  118  and a shaft  134  extending through the main body  126  of the head casting  118  along the first rotational axis  105 . The shaft  134  is rotatably supported by the support brackets  133  and is coupled to the handle  104  for co-rotation therewith about the rotational axis  105 . The shaft  134  may include a plurality of segments coupled together by one or more fasteners, or the shaft  134  may be formed as a unitary structure. The manual trip assembly  102  also includes a link  142  coupled for co-rotation with the shaft  134  (e.g., by a plurality of fasteners). The link  142  includes a first end  142   a  pivotally coupled to a first end  106   a  of the yoke  106  by a first pin  162  for relative pivotal movement about a second rotational axis  143  parallel to the first rotational axis  105 . A second end  142   b  of the link  142  opposite the first end  142   a  provides an input to a mechanical interlock assembly  144 . 
     The mechanical interlock assembly  144  includes a lost motion member  146 , an actuating member  150 , a spring  154 , and a blocking plunger  158 . As described in greater detail below, the blocking plunger  158  of the mechanical interlock assembly  144  is movable from a retracted position ( FIGS. 7-8 ) to an extended position ( FIG. 9 ) in which the blocking plunger  158  is engageable with the output shaft  94  to lock the movable contact  66  in its open position, thereby preventing the electromagnetic actuator  98  from reclosing the contacts  66 ,  70 . The lost motion member  146  delays movement of the blocking plunger  158  from the retracted position to the extended position until the contacts  66 ,  70  have been opened and the collar  110  of the output shaft  94  has moved below the blocking plunger  158 . 
     Referring to  FIG. 7 , the lost motion member  146  has an arcuate shape, and a second pin  170  pivotally couples a first end  174  of the lost motion member  146  to the second end  142   b  of the link  142 . A third pin  176  couples a second end  178  of the lost motion member  146  to the actuating member  150 . The third pin  176  is slidably received within an arcuate slot  182  in the lost motion member  146 . The arcuate slot  182  defines a lost motion region that allows for limited movement of the lost motion member  146  relative to the actuating member  150 . 
     Referring to  FIGS. 6-9  the blocking plunger  158  is received within a plunger housing  188  that is fixed to the support brackets  133 . The actuating member  150  is pivotally coupled to the plunger housing  188  by a fourth pin  192 . The actuating member  150  is also coupled to the blocking plunger  158  by an intermediate link  196 . As such, pivotal movement of the actuating member  150  about the fourth pin  192  imparts movement to the blocking plunger  158 . In the illustrated embodiment, a guide pin  200  extends through the blocking plunger  158  and interfaces with the plunger housing  188 . The guide pin  200  and the plunger housing  188  constrain movement of the blocking plunger  158  to generally linear movement along the plunger housing  188 . 
     Referring again to  FIG. 6 , a second end  106   b  of the yoke  106  is pivotally coupled to a fifth pin  202  extending between and fixed to the support brackets  133 . As such, the yoke  106  is pivotable about a third rotational axis  203  extending centrally through the fifth pin  202 . The third rotational axis  203  is parallel to both the first rotational axis  105  and the second rotational axis  143 . 
     With reference to  FIG. 10 , the yoke  106  includes a projection  206  that is engageable with the collar  110  on the output shaft  94  to move the output shaft  94  downward (in the direction of arrow  207  in  FIG. 10 ) and thereby open the contacts  66 ,  70  in response to actuation of the manual trip assembly  102 . The handle  104 , the link  142 , and the yoke  106  provide a compound lever arrangement to allow the manual trip assembly  102  to overcome the strong magnetic holding force of the permanent magnet  100  when the contacts  66 ,  70  are closed. 
     In the illustrated embodiment, the handle  104  defines a first distance L 1  from the center of an aperture  204  in the handle  104  to the first rotational axis  105  (the aperture  204  may be configured to receive a hook to facilitate operating the manual trip assembly  102  when the recloser  10  is mounted on a pole, for example). The link  142  defines a second distance L 2  from the first rotational axis  105  to the second rotational axis  143 . The yoke  106  defines a third distance L 3  from the second rotational axis  143  to the third rotational axis  203 . Finally, the yoke  106  also defines a fourth distance L 4  from the third rotational axis  203  to the point of engagement between the projection  206  and the collar  110 . 
     The handle  104  and link  142  define a first, second-class lever, and the yoke  106  and link  142  define a second, second-class lever. The two levers combine their respective mechanical advantages to apply a large axial force to the collar  110  while minimizing the length L 1  of the handle  104 . It is advantageous to minimize the length L 1  of the handle  104  in order to provide the recloser  10  with a compact overall size (i.e. to avoid the handle  104  from protruding significantly beyond the housing assembly  14 ). 
     For example, in some embodiments, the manual trip assembly  102  may apply sufficient force to the collar  110  to overcome a resistance force R of about 5,000 N (e.g., due to the permanent magnet  100 ) and thereby open the contacts  66 ,  70  by applying a torque T of about 90 ft-lbs or less via the handle  104 . The required torque T is provided by applying a force E on the handle  104  at the aperture  204 . The force E can be calculated according to the following equation: 
         E=R*L 2/L1*L4/L3   Equation(1)
 
     Because L 2  is much smaller than L 1  in the illustrated embodiment, and L 4  is smaller than L 3 , it is evident from Equation (1) that the force E (i.e. the effort force required from the operator) is significantly less than the resistance force R. 
     In other embodiments, the manual trip assembly  102  may include other mechanisms for amplifying the force applied on the handle  104  in order to overcome the resistance force R. For example, the manual trip assembly  102  may include one or more hydraulic or pneumatic actuators, pulleys, linkages, or other suitable mechanisms coupled between the handle  104  and the collar  110 . 
     With reference to  FIG. 6 , in the illustrated embodiment, the recloser  10  includes first and second state sensors  210 ,  214  configured to detect the state of the manual trip assembly  102  (i.e. whether the handle  104  is actuated or unactuated) and the state of the VI assembly  18  (i.e. whether the contacts  66 ,  70  are open or closed). The state sensors  210 ,  214  may communicate this information to the controller of the recloser  10 . In the illustrated embodiment, the state sensors  210 ,  214  are configured as electrical contacts (e.g., microswitches) responsive to movement of the shaft  134  and the output shaft  94 , respectively. In other embodiments, any other types of sensors (e.g., Hall-effect sensors or the like) for determining the state of the manual trip assembly  102  and the VI assembly  18  may be used. 
     Exemplary operating sequences of the recloser  10  according to certain embodiments of the present disclosure will now be described. 
     With reference to  FIG. 2 , during operation, the controller of the recloser  10  may receive feedback from the sensor assembly  78  indicating that a fault has occurred. In response to this feedback, the controller may initiate a circuit breaking sequence. In the circuit breaking sequence, the controller automatically energizes the coil  99  of the electromagnetic actuator  98 . The resultant magnetic field generated by the coil  99  moves the plunger  103  and the output shaft  94  in an opening direction (i.e. downward in the orientation of  FIG. 2 ). This movement greatly reduces the magnetic holding force of the permanent magnet  100  on the plunger  103 . For example, in some embodiments, the plunger  103  may have a resilient construction and retract inwardly and away from the permanent magnet  100  as the plunger  103  moves in the opening direction, thereby creating an air gap between the plunger  103  and the magnet  100 . In other embodiments, the width of the plunger  103  may decrease in the opening direction to create an air gap between the plunger  103  and the magnet  100 . In yet other embodiments, the plunger  103  may include one or more non-magnetic regions and/or a reduced volume of magnetic material that may move into proximity with the permanent magnet  100  as the plunger  103  moves in the opening direction. 
     With the holding force of the permanent magnet  100  reduced, the spring  101  is able to overcome the holding force of the permanent magnet  100  and accelerate the output shaft  94  in the opening direction. As such, the coil  99  need only be energized momentarily to initiate movement of the output shaft  94 , advantageously reducing the power drawn by the electromagnetic actuator  98  and minimizing heating of the coil  99 . 
     The output shaft  94  moves the drive shaft  86  with it in the opening direction. As the drive shaft  86  moves in the opening direction, the encapsulated spring  90 , which is compressed when the contacts  66 ,  70  are closed, begins to expand. The spring  90  thus initially permits the drive shaft  86  to move in the opening direction relative to the movable contact  66  and maintains the movable contact  66  in fixed electrical contact with the stationary contact  70 . As the drive shaft  86  continues to move and accelerate in the opening direction under the influence of the spring  101 , the spring  90  reaches a fully expanded state. When the spring  90  reaches its fully expanded state, the downward movement of the drive shaft  86  is abruptly transferred to the movable contact  66 . This quickly separates the movable contact  66  from the stationary contact  70  and reduces arcing that may occur upon separating the contacts  66 ,  70 . By quickly separating the contacts  66 ,  70 , degradation of contacts  66 ,  70  due to arcing is reduced, and the reliability of the VI assembly  18  is improved. 
     The controller may then receive feedback from the sensor assembly  78  indicating that the fault has been cleared and initiate a reclosing sequence. In additional and/or alternative embodiments, the controller may initiate the reclosing sequence after waiting a predetermined time period after the fault was originally detected, or in response to receiving a signal from an external controller commanding the controller to initiate the reclosing sequence. In the reclosing sequence, the controller energizes the coil  99  in an opposite current direction. The resultant magnetic field generated by the coil  99  moves the output shaft  94  (and with it, the drive shaft  86  and the movable contact  66 ) in a closing direction (i.e. upward in the orientation of  FIG. 2 ). 
     The movable contact  66  comes into contact with the fixed contact  70 , restoring a conductive path between the terminals  34 ,  38 . The output shaft  94  and drive shaft  86  continue to move in the closing direction, compressing each of the springs  90 ,  101  to preload the springs  90 ,  101  for a subsequent circuit breaking sequence. As the output shaft  94  approaches the end of its travel, the plunger  103  of electromagnetic actuator  98  is influenced by the permanent magnet  100 , which latches the plunger  103  in its starting position. The coil  99  may then be de-energized. In some embodiments, the coil  99  may be de-energized a predetermined time period after the contacts  66 ,  70  are closed. This delay may inhibit the movable contact  66  from rebounding back to the open position. 
     In some circumstances, an operator may opt to manually initiate a circuit breaking operation to open the contacts  66 ,  70  using the manual trip assembly  102 . To do so, the operator may apply a force E ( FIG. 10 ) to the handle  104 , which is conveniently accessible from the exterior of the housing assembly  14  ( FIG. 1 ). In some embodiments, the handle  104  may be a contrasting color from the housing assembly  14 . For example, the handle  104  may be a high-visibility color, such as yellow, to allow the handle  104  to be easily visible to the operator. 
     As the operator applies the force E, the handle  104 , the shaft  134 , and the link  142  pivot from an initial or unactuated state, illustrated in  FIG. 7 , about the first rotational axis  105  generally in the direction of arrow  218 . This causes the yoke  106  to pivot downward about the third rotational axis  203 , such that the projection  206  bears against the collar  110  on the output shaft  94  ( FIG. 10 ). As discussed above, the compound lever action of the handle  104 , link  142 , and yoke  106  amplifies the force E. The first end  106   a  of the yoke  106  moves downward, and the projection  206  bears against the collar  110  on the output shaft  94  with a force sufficient to overcome the holding force of the permanent magnet  100 . The drive shaft  94  then begins to move downward in the direction of arrow  207 . 
     As the operator pivots the handle  104  in the direction of arrow  218 , the lost motion member  146  is moved upward by the link  142 , and the third pin  176  travels along the slot  182 . As such, the actuating member  150  and the plunger  158  remains stationary during an initial travel range of the handle  104 . The slot  182  is sized such that the actuating member  150  remains stationary until the handle  104  reaches an intermediate position ( FIG. 8 ). In the illustrated embodiment, the initial travel range is about 27 degrees (i.e. the handle  104  rotates 27 degrees before the third pin  176  reaches the end of the slot  182 ). In other embodiments, the slot  182  may be configured to provide different degrees of lost motion to suit a particular configuration of the recloser  10 . 
     Within the initial travel range of the handle  104 , the downward movement of the drive shaft  94  reduces the holding force of the permanent magnet  100  on the plunger  103  as described above. With the holding force of the permanent magnet  100  reduced, the spring  101  is able to overcome the holding force of the permanent magnet  100  and accelerate the output shaft  94  in the opening direction, opening the contacts  66 ,  70  in the same manner as the circuit breaking sequence described above. 
     The lost motion member  146  delays movement of the blocking plunger  158  from the retracted position to the extended position until the contacts  66 ,  70  have been opened and the collar  110  of the output shaft  94  has moved below the blocking plunger  158 . Once the handle  104  has reached the intermediate position and the contacts  66 ,  70  have been opened, the operator continues to rotate the handle  104  in the direction of arrow  218 . With the third pin  176  engaged with the end of the slot  182 , the continued rotation of the link  142  with the handle  104  and resultant upward movement of the lost motion member  146  pivots the actuating member  150  about the fourth pin  192 . The actuating member  150  in turn drives the blocking plunger  158  forward toward the extended position and into the path of the collar  110  ( FIG. 9 ). With the blocking plunger  158  in the extended position, the blocking plunger  158  is engageable with the output shaft  94  to lock the movable contact  66  in its open position, thereby preventing the electromagnetic actuator  98  from reclosing the contacts  66 ,  70 . 
     In addition to the mechanical interlock provided by the blocking plunger  158 , in some embodiments, the controller may determine that the manual trip assembly  102  has been actuated based on feedback from the state sensors  210 ,  214  ( FIG. 6 ). In such embodiments, the state sensors  210 ,  214  and the controller may act as an electronic interlock assembly to prevent actuation of the electromagnetic actuator  98 . For example, the controller may initiate an electronic interlock function to prevent the electromagnetic actuator  98  from reclosing the contacts  66 ,  70  until the controller determines that the handle  104  of the manual trip assembly  102  has been returned to its initial or unactuated position. By including both electronic and mechanical interlocks, the recloser  10  may be more safely controlled and serviced. 
     To disengage the interlock assembly  144 , the operator pivots the handle  104  in the opposite direction, returning the plunger  158  to its retracted position ( FIGS. 7-8 ) and lifting the collar  110 . Once the controller determines that the handle  104  has been fully returned to its initial or unactuated position (e.g., via the state sensor  210 ), the controller may disable the electrical interlock. The contacts  66 ,  70  can then be reclosed via the electromagnetic actuator  98  in the manner described above. 
     Although the invention has been described in detail with reference to certain preferred embodiments, variations and modifications exist within the scope and spirit of one or more independent aspects of the invention as described. 
     Various features and advantages of the invention are set forth in the following claims.