INTERLOCK FOR CIRCUIT INTERRUPTING DEVICE

[0001] The present application is a continuation-in-part of co-pending U.S. patent application Ser. No. 14/292,142, filed May 30, 2014, which is a continuation of U.S. patent application Ser. No. 13/476,529, filed on May 21, 2012, now U.S. Pat. No. 8,772,666, issued on Jul. 8, 2014, which claims priority to U.S. Provisional Patent Application No. 61/633,430, filed on Feb. 9, 2012, the entire contents of which are incorporated by reference herein in their entirety.

[0002] Circuit-interrupting devices (i.e., switches) include load-breakers, such as vacuum interrupters, that are used to control the flow of electricity through the switch. For example, vacuum interrupters typically include a stationary contact, a moveable contact, and a mechanism for moving the movable contact. To open the electrical circuit defined by the switch, the movable contact is separated from the stationary contact.

[0003] For safety precautions, a visible disconnect can be provided in series with the load-breaker to provide visual verification of whether the circuit is open. In particular, the visible disconnect can have an open state and a closed state. In the closed state, the visible disconnect physically and electrically connects the load-breaker with an electricity source (e.g., a source conductor). In the open state, the visible disconnect physically and electrically disconnects the load-breaker from the electricity source. However, to prevent unsafe arcing across the visible disconnect, the load-breaker must be opened (i.e., the movable contact must be separated from the stationary contact) to create an isolated switch before the visible disconnect can be safely opened (i.e., before the visible disconnect can be changed from the closed state to the open state). Similarly, the visible disconnect must be changed from the open state to the closed state before the load-breaker can be returned to its closed state where the moveable contact is rejoined with the stationary contact.

[0004] Furthermore, in some situations, the load-breaker may malfunction. For example, an operating mechanism that allows an operator to open or close the load-breaker (e.g., separate the contacts of a vacuum interrupter) may malfunction and the movement of the operating mechanism may not be transferred to the load-breaker. Also, in some situations, the contacts of a vacuum interrupter may be subject to pre-arcing that causes the moveable contact to become welded to the stationary contact. In this situation, when the welded joint is strong enough to prevent the operating mechanism from separating the contacts, the contacts will not separate even if an operator drives the operating mechanism to open the load-breaker. When the contacts do not physically separate, it is unsafe to allow an operator to change the state of the visible disconnect.

[0005] Similarly, in some situations, the switch may include safety systems (e.g., an interlock system or a triggering system) that ensure a proper operational sequence of the load-breaker and the visible disconnect. These safety systems, however, may also malfunction or may be improperly by-passed or disabled by an operator, which creates safety concerns.

[0006] Therefore, embodiments of the invention provide mechanisms for ensuring that the load-breaker is disconnected from the source conductor before an operator is able to change the state of the visible disconnect. In particular, one embodiment of the invention provides a circuit-interrupting device including a load-breaker having a first contact and a second contact, wherein the second contact is movable between a first position P₁ and a second position P₂. The circuit-interrupting device also includes a first operating mechanism for actuating movement of the second contact and a first assembly for controlling movement of the first operating mechanism. The first assembly includes a first extension movable to operate the first assembly. The device further includes a visible disconnect in series with the load-breaker, wherein the visible disconnect has an open state and a closed state. In addition, the device includes a second operating mechanism for actuating the visible disconnect between the open state and the closed state and a second assembly for controlling movement of the second operating mechanism. The second assembly includes a second extension movable to operate the second assembly. Furthermore, the device includes an interlock system that prevents movement of at least one component of the second assembly when the second contact is not in the second position P₂, wherein the interlock system operates independently of the first extension and the second extension.

[0007] Another embodiment of the invention provides a circuit-interrupting device comprising a gearbox, a visible disconnect, and a load-breaker in series with the visible disconnect. The circuit-interrupting device also includes a first operating mechanism for actuating the load-breaker between an open state and a closed state and a second mechanism for actuating the visible disconnect between an open state and a closed state. In addition, the device includes a first assembly controlling movement of the first operating mechanism and a second assembly controlling movement of the second operating mechanism. The device further includes an interlock system external to the gearbox and an interlock system internal to the gearbox. The external interlock system coordinates operation of the first assembly and the second assembly. The internal interlock system includes a cam and a bias-driven follower. The cam is driven by a shaft between a first cam state when the load-breaker is in the open state and a second cam state when the load-breaker is in the closed state. The bias-driven follower has a first follower state when the cam is in the first cam state and has a second follower state when the cam is in the second cam state. The bias-driven follower blocks movement of at least one component of the second assembly when the bias-driven follower is in the second follower state.

[0008] Yet another embodiment of the invention provides an interlock system for a circuit-interrupting device, the circuit-interrupting device including a gearbox, a load-breaker in series with a visible disconnect, and an assembly for driving the visible disconnect between an open state and a closed state. The interlock system includes a cam and a bias-driven follower. The cam is coupled to a shaft and is driven by the shaft between a first cam state when the load-breaker is in an open state and a second cam state when the load-breaker is in a closed state. The bias-driven follower has a first follower state when the cam is in the first cam state and has a second follower state when the cam is in the second cam state. In the second follower state, the bias-driven follower blocks movement of at least one component of the assembly. The cam and the bias-driven follower are internal to the gearbox.

[0009] Yet another embodiment of the invention provides a circuit-interrupting device including a load-breaker operable between an open state and a closed state, and a first interlock member operatively associated with the load-breaker. The first interlock member moves between a first position and a second position when the load-breaker moves between the closed state and the open state. The circuit-interrupting device further includes a disconnect switch that moves between an open state and a closed state. When the load-breaker is in the closed state, the first interlock member is in the first position and contacts the disconnect switch to prevent the disconnect switch from moving from the closed state to the open state.

[0010] Yet another embodiment of the invention provides an interlock system for a circuit-interrupting device. The circuit interrupting device includes a load-breaker operable between an open state and a closed state and a disconnect switch in series with the load-breaker and having a blade movable between an open state and a closed state. The interlock system includes a first interlock member operably associated with the load-breaker. The first interlock member has a first interlock state when the load-breaker is in the closed position and a second interlock state when the load-breaker is in the open position. The first interlock member moves from the first interlock state to the second interlock state when the load-breaker moves to the open position. The first interlock member is in contact with a portion of the disconnect switch when the first interlock member is in the first interlock state to prevent the disconnect switch blade from moving from the closed state to the open state.

[0011] Yet another embodiment of the invention provides a circuit-interrupting device including a load-breaker having a first contact and a second contact. The second contact is movable relative to the first contact between a closed state and an open state. The circuit-interrupting device further includes a first operating mechanism for moving the second contact between the closed state and the open state, a first actuating assembly for controlling movement of the first operating mechanism, and a disconnect switch having a blade movable between a closed state and an open state. In addition, the circuit-interrupting device includes a second operating mechanism for moving the disconnect switch blade between the closed state and the open state, a second actuating assembly for controlling movement of the second operating mechanism. The circuit-interrupting device also includes a first interlock member coupled to the load-breaker for concurrent travel therewith to prevent, independently of the second actuating assembly, the disconnect switch blade from pivoting from the closed state to the open state when the second contact is in the closes state.

[0012] Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings.

[0034] Before any embodiments of the invention are explained in detail, it is to be understood that the invention 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 invention is capable of other embodiments and of being practiced or of being carried out in various ways.

[0035] FIGS. 1-3 illustrate a switch 10. The switch 10 includes a load-breaker (e.g., vacuum interrupter 12), a visible disconnect 14, a housing 16, and a generally transparent or translucent viewing window 18. The housing 16 at least partially encases the vacuum interrupter 12 and the visible disconnect 14. In some embodiments, the switch 10 includes a solid dielectric switch. In other embodiments, the switch 10 includes a gas-based or oil-based switch.

[0036] The vacuum interrupter 12 can include a first contact 19a and a second contact 19b that is moveable between a first position P₁ and a second position P₂. When the second contact 19b is in the first position P₁, the contacts 19a, 19b are connected or in contact with one another (see FIG. 1), the vacuum interrupter 12 is in a closed state, and the circuit is closed. Alternatively, when the second contact 19b is in the second position P₂, the contacts 19a, 19b are not connected (see FIGS. 2 and 3), the vacuum interrupter 12 is in an open state, and the circuit is open. The state of the vacuum interrupter 12 can be changed using a vacuum interrupter operating mechanism (e.g., an actuator) 20. The vacuum interrupter operating mechanism 20 can be operated manually or in an automated fashion.

[0037] In various embodiments, the vacuum interrupter operating mechanism 20 extends out of a top of the switch 10 (see FIG. 4a) and extends into a gearbox 17 coupled to the top of the switch 10 (see FIGS. 4e and 4f). As shown in FIGS. 4b-4f, the gearbox 17 includes an assembly 20a that controls movement of the mechanism 20 and can coordinate the movement of multiple mechanisms 20 when multiple switches 10 are used to control multiple power lines, e.g. for two- or three-phase power (e.g. see FIG. 4e). The assembly 20a can include a plurality of components for controlling movement of the vacuum interrupter operating mechanism 20. For example, as shown in FIG. 4c, the assembly 20a includes an extension 32 that can be driven or moved (e.g., rotated) by an operator or an automated controller. In some embodiments, a lever or a handle 35 can be connected to the extension 32 to aid an operator or an automated controller in rotating the extension 32. The assembly 20a can also include a rotatable shaft that translates rotation of the extension 32 to the vacuum interrupter operating mechanism 20. Various additional components, such as springs, linkages, couplings, pins, plates, frames, and additional shafts, can also be included in the assembly 20a and used to translate rotation of the extension 32 into movement of the vacuum interrupter operating mechanism 20, as is well known in the industry.

[0038] The visible disconnect 14 is connected in series with the vacuum interrupter 12. The visible disconnect 14 illustrated in FIGS. 1-3 includes a knife blade assembly that includes a blade 21 and a visible disconnect operating mechanism 22. The operating mechanism 22 can be operated manually or in an automated fashion to move the blade 21 between a closed state (see FIGS. 1 and 2) and an open state (see FIG. 3). For example, in some embodiments, the visible disconnect operating mechanism 22 pivots the blade 21 on a pin 23 or other pivoting mechanism between the two states. In the closed state, the blade 21 physically and electrically connects the vacuum interrupter 12 with a source conductor 24. In the open state, the blade 21 physically and electrically disconnects the vacuum interrupter 12 from the source conductor 24. Therefore, the physical position of the blade 21 can be used to visually inspect whether the vacuum interrupter 12 is physically and, consequently, electrically connected to the source conductor 24. Therefore, the physical position of the blade 21 provides visual verification to an operator regarding whether current may be flowing through the switch 10.

[0039] As shown in FIG. 4a, the visible disconnect operating mechanism 22 extends out of a top of the switch 10 and extends into the gearbox 17 coupled to the top of the switch 10 (see FIGS. 4e and 4f). As shown in FIGS. 4b-4f, the gearbox 17 includes an assembly 22a that controls movement of the mechanism 22 and can coordinate the movement of multiple mechanisms 22 when multiple switches 10 are used to control multiple power lines, e.g. for two- or three-phase power (e.g. see FIG. 4e). The assembly 22a can include a plurality of components for controlling movement of the visible disconnect operating mechanism 22. For example, as shown in FIG. 4c, the assembly 22a includes an extension 34 that can be driven or moved (e.g., rotated) by an operator or an automated controller. In some embodiments, a lever or a handle 35 can be connected to the extension 34 to aid an operator or an automated controller in rotating the extension 34. The assembly 22a can also include a rotatable shaft that translates rotation of the extension 34 into movement of the visible disconnect operating mechanism 22. Various additional components, such as springs, linkages, couplings, pins, plates, frames, and additional shafts, can also be included in the assembly 22a and used to translate rotation of the extension 34 into movement of the visible disconnect operating mechanism 22, as is well known in the industry.

[0040] As described above, to prevent unsafe arcing, the vacuum interrupter 12 must be opened before the visible disconnect 14 can be opened or closed. To coordinate this required operational sequence, the switch 10 can include (as shown in FIG. 5) an external interlock system 30. The external interlock system 30 is mounted to an external wall 31 of the gearbox 17. As illustrated in FIGS. 4c and 5, the external interlock system 30 includes a cam piece 36 associated with the first extension 32 and a cam piece 37 associated with the second extension 34. The cam pieces 36, 37 rotate with the extensions 32, 34, respectively, and the shape and placement of the cam pieces 36, 37 mechanically require that an operator move (e.g., rotate) the first extension 32 before the operator can move (e.g., rotate) the second extension 34. In particular, as shown in FIG. 4c, the shape of the cam piece 36 blocks the cam piece 37 and the associated second extension 34 from rotating until the first extension 32 and the cam piece 36 are rotated to an open position. Therefore, due to the configuration of the cam pieces 36, 37, an operator (e.g., either manually or in an automated fashion) must open the vacuum interrupter 12 before the operator can change the state of the visible disconnect 14. This operational sequence ensures that all of the load-breaking occurs in the vacuum interrupter 12 rather than in the visible disconnect 14.

[0041] As noted above, in some embodiments, even if an operator uses the assembly 20a to open the vacuum interrupter 12 (i.e., rotates the first extension 32), the second contact 19b may not be displaced from the first position P₁ to the second position P₂ (e.g., due to a malfunction in the operating mechanism 20 or due to the contacts 19a and 19b being welded together). In this situation, it is unsafe to allow an operator to change the state of the visible disconnect 14. The external interlock system 30 described above, however, will not, by itself, prevent the operator from changing the state of the visible disconnect 14 in this situation. Rather, as long as the operator has moved the first extension 32 (which rotates the cam piece 36 to a position where it no longer blocks rotation of the cam piece 37 and the associated second extension 34), the external interlock system 30 allows the operator to move the second extension 34 to change the state of the visible disconnect 14.

[0042] To address this concern, the switch 10 includes an internal interlock system 40 (see FIGS. 4d, 4f, 6a, and 6b). As shown in FIGS. 4d, 4f, 6a, and 6b, the internal interlock system 40 is positioned inside the gearbox 17. Therefore, as compared to the external interlock system 30, the internal interlock system 40 is invisible to an operator, which can prevent an operator from disabling or by-passing the internal interlock system 40. The internal interlock system 40 operates independently of the external interlock system 30 and the extensions 32, 34 controlling the assemblies 20a, 22a. As described in more detail below, the internal interlock system 40 prevents actuation of the assembly 22a associated with the visible disconnect 14 through the second extension 34 until the vacuum interrupter 12 is open (i.e., until the second contact 19b is in the second position P₂) independent of the operation of the extensions 32, 34 and the external interlock system 30. In particular, the internal interlock system 40 mechanically prevents at least one component of the assembly 22a from moving and changing the state of the visible disconnect 14 until the vacuum interrupter 12 is open.

[0043] FIGS. 7a through 7c illustrate the internal interlock system 40 in greater detail. As shown in FIGS. 7a through 7c, the internal interlock system 40 includes a cam 42 and a bias-driven follower 44 (e.g., biased by a spring 45). The bias-driven follower 44 is attached to a frame 54 that at least partially encloses at least a portion of the assembly 22a. The cam 42 is coupled to a shaft 46, which is driven by the position of the second contact 19b of the vacuum interrupter 12 through a link in the assembly 20a (see, e.g., FIG. 4f). Therefore, the shaft 46 drives the cam 42 between a first cam state when the vacuum interrupter 12 is in the open state (see FIG. 8) and a second cam state when the vacuum interrupter 12 is in the closed state (see FIG. 9).

[0044] As shown in FIGS. 7a through 7c, the cam 42 includes an actuation arm 48 that has a first contact surface 50 and a second contact surface 52. The first and second contact surfaces 50 and 52 of the actuation arm 48 can interact with the follower 44. The follower 44 includes a first portion 56 and a second portion 58. The first portion 56 of the follower 44 is moveable through an opening 60 in the frame 54. The follower 44 is pivotable about a pin 61 or other pivoting mechanism between a first follower state (see FIG. 8) and a second follower state (see FIG. 9).

[0045] During operation, the internal interlock system 40 ensures that the operational sequence of the vacuum interrupter 12 and the visible disconnect 14 described above is maintained even in the situation where, although the operator has rotated the first extension 34 to drive the assembly 20a to open the vacuum interrupter 12, the vacuum interrupter 12 does not open (e.g., the operating mechanism 20 and/or the external interlock system 30 malfunctions or is improperly by-passed or the contacts 19a and 19b have become welded together).

[0046] For example, as described above, the visible disconnect operating mechanism 22 is movable to change the state of the visible disconnect 14 (i.e., open or close the visible disconnect 14). The visible disconnect operating mechanism 22 is coupled to the assembly 22a (see FIGS. 4f and 7c), which translates rotation of the second extension 34 into movement of the visible disconnect operating mechanism 22. However, as shown in FIG. 9, at least one component of the assembly 22a (e.g., a rotating plate controlled by a spring) may be blocked by the follower 44 when the internal interlock system 40 is engaged or placed in a locked state. The internal interlock system 40 is placed in the locked state when the contacts 19a, 19b of the vacuum interrupter 12 are not separated (i.e., the second contact 19b is not in the second position P₂).

[0047] In particular, when the contacts 19a, 19b of the vacuum interrupter are closed or connected (i.e., the second contact 19b is in the first position P₁), the shaft 46 rotates to position the cam 42 in the second cam state (i.e., a locked position), as shown in FIG. 9. With the cam 42 in the second cam state, the actuation arm 48 of the cam 42 is positioned such that the first contact surface 50 contacts the second portion 58 of the follower 44. With the first contact surface 50 contacting the second portion 58, the follower 44 is forced against its bias (against the spring 45) to the second follower state. As shown in FIG. 9, in the second follower state, the follower 44 is positioned such that the first portion 56 extends through the opening 60 in the frame 54 and blocks movement of at least one component of the assembly 22a. Under these conditions, the follower 44 allows the assembly 22a to be charged (e.g., allows a spring 64 associated with the assembly 22a to be charged), but prevents the release of energy needed to open the visible disconnect 14. This design ensures that the operator cannot put extra force on the cam 42 and the follower 44 (e.g., through the assembly 22a) that could override the internal interlock system 40.

[0048] Conversely, when the contacts 19a, 19b of the vacuum interrupter are open or separated (i.e., the second contact 19b is in the second position P₂), the shaft 46 rotates to position the cam 42 in the first cam state (i.e., an unlocked position), as shown in FIG. 8. With the cam 42 in the first cam state, the actuation arm 48 of the cam 42 is positioned such that the first contact surface 50 disengages from the second portion 58 of the follower 44, such that the cam 42 no longer forces the follower 44 against the bias (i.e., against the force of the spring 45). Therefore, the follower 44 rotates based on the force of the spring 45 to the first follower state (i.e., a resting state). In the first follower state, the second portion 58 of the follower 44 rests on the second contact surface 52 of the cam 42. As shown in FIG. 8, in the first follower state, the follower 44 is positioned such that the first portion 56 of the follower 44 no longer blocks movement of the at least one component of the assembly 22a.

[0049] Alternatively, in some embodiments, when the cam 42 is rotated by the shaft 46 into an unlocked position, the cam 42 no longer engages with the follower 44. For example, the shaft 46 can rotate the cam 42 into engagement with the follower 44 to engage or lock the internal interlock system 40 and can rotate the cam 42 out of engagement with the follower 44 to disengage or unlock the internal interlock system 40. In particular, when the cam 42 is in a locked position, the cam 42 contacts the second portion 58 of the follower 44 and pushes the second portion 58 against the frame 54 (but may not necessarily extend the first portion 56 further through the opening 60) and into a second follower state. In this state, the follower 44 is held rigidly against the frame 54 by the cam 42 such that follower 44 cannot move. With the follower 44 held in this rigid position, the first portion 56 of the follower 44 is positioned in the path of at least one movable component of the assembly 22a and, consequently, blocks movement of the component. Alternatively, when the cam 42 is in the unlocked position, the cam 42 is positioned such that it no longer contacts the follower 44 (see FIGS. 7a-7c), and the follower 44 assumes the first follower state (i.e., a resting state) where it can freely rotate on the pivot 61. In this state, when the at least one component of the assembly 22a attempts to move (e.g., rotates), the component pushes on the first portion 56 of the follower 44, which causes the follower 44 to pivot and move out of the way of the component. Accordingly, when the cam 42 is in an unlocked position, the assembly 22a can push the follower 44 out of the way because the follower 44 is not restricted from rotating by the cam 42.

[0050] Therefore, to properly open the vacuum interrupter 12 and in turn, to properly open the visible disconnect 14, an operator uses the assembly 20a (e.g., via the first extension 32) to move the vacuum interrupter mechanism 20, which changes the vacuum interrupter 12 from the closed to the open state (i.e., moves the second contact 19b from the first position P₁ to the second position P₂). As described above, the separation of the second contact 19b from the first contact 19a rotates the shaft 46, which moves the cam 42 of the internal interlock system 40 to the unlocked state. In the unlocked state, the follower 44 assumes the first follower state where it no longer blocks movement of the at least one component of the assembly 22a. Therefore, the operator can use the assembly 22a to open the visible disconnect 14 (i.e., by rotating the second extension 34). In the open state, the blade 21 of the visible disconnect 14 disconnects the vacuum interrupter 12 from the source conductor 24 and provides visual verification to an operator that the circuit is open (i.e., vacuum interrupter 12 is physically and electrically disconnected from the source conductor 24).

[0051] Similarly, to reestablish a working circuit in the switch 10 after the vacuum interrupter 12 has been opened, an operator first uses the assembly 22a to close the visible disconnect 14 (e.g., by rotating the extension 34). With the visible disconnect 14 in the closed state, the blade 21 of the visible disconnect 14 physically and electrically connects the vacuum interrupter 12 with the source conductor 24. After the visible disconnect 14 has been closed, the operator can use the assembly 20a (e.g., the first extension 32) to close the vacuum interrupter 12 (i.e., to move the second contact 19b of the vacuum interrupter 12 from the second position P₂ to the first position P₁). When the vacuum interrupter 12 is closed, the shaft 46 rotates the cam 42 to engage the follower 44 and block movement of at least one component of the assembly 22a. Therefore, with the internal interlock system 40 engaged, the visible disconnect 14 cannot be changed to the open state using the assembly 22a.

[0052] The sequences of events defined by the interlock systems 30 and 40 ensure that the visible disconnect 14 is only in the open state when the circuit is broken (i.e., when the second contact 19b in the second position P₂).

[0053] It should be understood that the cam-and-follower configuration illustrated in the internal interlock 40 is only one configuration for preventing movement of at least one component of the assembly 22a when the vacuum interrupter 12 is not open. In particular, more or fewer components may be used to perform this function. Also the cam 42 and the follower 44 can take on other shapes and configurations, and the cam 42 and the follower 44 can be used to block movement of various components of the assembly 22a and/or the operating mechanism 22 itself. In addition, it should be understood that although the terms “internal” and “external” have been used to describe the interlock systems 30 and 40, these systems can be placed at various locations of the switch 10 and the gearbox 17 and, in some embodiments, may both be internal or may both be external to the gearbox 17.

[0054] It should also be understood that the internal interlock system 40 can be used without also using the external interlock system 30. For example, because the internal interlock system 40 blocks movement of at least one component of the assembly 22a operating the visible disconnect operating mechanism 22 unless the second contact 19b of vacuum interrupter 12 is in the second position P₂, the internal interlock system 40 provides a similar safety system as the external interlock system 30. Furthermore, because the internal interlock system 40 is located inside the gearbox 17, the system 40 is less likely to be by-passed or disabled by operators. However, the external interlock system 30 may be used in conjunction with the internal interlock system 40 to provide visual reminders to an operator regarding the operational sequence required to open or close the circuit (e.g., via the cam pieces 36, 37). Furthermore, using the two interlock systems 30 and 40 may provide additional diagnostic information to an operator regarding the switch 10. For example, if the operator has rotated the extension 32 to open the vacuum interrupter 12 but the internal interlock system 40 continues to prevent movement of the assembly 22a, including the second extension 34, the operator knows the switch 10 is malfunctioning (e.g., the contacts 19a and 19b might have become welded together) and that maintenance is required.

[0055] While the invention is described in terms of several preferred embodiments of circuit or fault interrupting devices, it will be appreciated that the invention is not limited to circuit interrupting and disconnect devices. The inventive concepts may be employed in connection with any number of devices including circuit breakers, reclosers, and the like. Also, it should be understood that the switch 10 can include a single-phase interrupting device or a multi-phase (e.g., a three phase) interrupting device.

[0056] With reference to FIGS. 10-14A, an alternative embodiment of a switch 110 (i.e., a circuit-interrupting device) is illustrated. The switch 110 includes a load-breaker (e.g., a vacuum interrupter) 112, a visible disconnect 114, a housing 116, and a generally transparent or translucent viewing window 118. The housing 116 at least partially encases the vacuum interrupter 112 and the visible disconnect 114. In some embodiments, the switch 110 includes a solid dielectric switch. In other embodiments, the switch 110 includes a gas-based or oil-based switch.

[0057] The vacuum interrupter 112 includes a first contact 119a and a second contact 119b movable between a first position (FIG. 12) and a second position (FIGS. 13 and 14). When the second contact 119b is in the first position the contacts 119a, 119b are connected or in contact with one another, the vacuum interrupter 112 is in a closed state, and the circuit is closed. Alternatively, when the second contact 119b is in the second position, the contacts 119a, 119b are not connected, the vacuum interrupter 112 is in an open state, and the circuit is open. The state of the vacuum interrupter 112 can be changed using a vacuum interrupter operating mechanism 120 (e.g., an actuator). The vacuum interrupter operating mechanism 120 can be operated manually or in an automated fashion. With reference to FIG. 10, the vacuum interrupter operating mechanism 120 extends out of a top of the switch 110 and extends into a gearbox similar to the gearbox 17 described above and shown in FIGS. 4e and 4f. The gearbox (not shown) includes a vacuum interrupter operating assembly similar to the assembly 20a that controls the movement of the vacuum interrupter operating mechanism 120.

[0058] The visible disconnect 114 is connected in series with the vacuum interrupter 112. The visible disconnect 114 illustrated in FIG. 11 includes a knife blade assembly with a blade 121 and a visible disconnect operating mechanism 122. The operating mechanism 122 can be operated manually or in an automated fashion to move the blade 121 between a closed state (FIGS. 11-13) and an open state (FIG. 14). The visible disconnect operating mechanism 122 extends out of a top of the switch 110 and into the aforementioned gearbox coupled to the top of the switch 110. The gearbox also includes a visible disconnect operating assembly, similar to the assembly 22a, that controls movement of the visible disconnect operating mechanism 122. In some embodiments, the visible disconnect operating mechanism 122 pivots the blade 121 on a pin 123 (i.e., a pivot point) or other pivoting mechanism between the two states. In the closed state, the blade 121 physically and electrically connects the vacuum interrupter 112 with a source conductor 124. In the open state, the blade 121 physically and electrically disconnects the vacuum interrupter 112 from the source conductor 124. Therefore, the position of the blade 121 can be used to visually inspect whether the vacuum interrupter 112 is physically and, consequently, electrically connected to the source conductor 124, i.e., the blade 121 position. As described above, to prevent unsafe arcing, the vacuum interrupter 112 must be opened before the visible disconnect 114 can be opened or closed. To coordinate this required operational sequence, the switch 110 includes an internal interlock system 140 with a first interlock member 141 operatively associated with the vacuum interrupter 112 and a second interlock member 142 operatively associated with the visible disconnect 114. Referring also to FIG. 12A, the first interlock member 141 includes a base portion 144 at least partially surrounding a segment of the vacuum interrupter operating mechanism 120 and a blocking portion 145 with a beveled surface 143. The base portion 144 is coupled to the vacuum interrupter operating mechanism 120 such that the first interlock member 141 is movable (translatable) between a first position (i.e., a first interlock state) (FIG. 12) and a second position (i.e., a second interlock state) (FIGS. 13 and 14). In particular, the first interlock member 141 moves between the first position and the second position when the vacuum interrupter 112 moves between the closed state and the open state, respectively. Specifically, the first interlock member 141 moves from the first interlock state to the second interlock state when the vacuum interrupter 112 moves to the open position.

[0059] The second interlock member 142 is fixedly coupled to the blade 121 of the visible disconnect 114, and may be considered a part of the visible disconnect 114. The second interlock member 142 is configured to co-rotate with the blade 121 about the pin 123 when the blade 121 moves between the open state and the closed state. Specifically, the second interlock member 142 includes two outer side members 146 (FIG. 11), each having a flat portion 147 and a curved portion 148.

[0060] In operation, the internal interlock system 140 ensures that the operational sequence of the vacuum interrupter 112 and the visible disconnect 114 described above is maintained. For example, as described above, the visible disconnect operating mechanism 122 is moveable to change the state of the visible disconnect 114 (i.e., open or close the visible disconnect). However, as shown in FIGS. 12 and 12A, when the vacuum interrupter 112 is in the closed state, the first interlock member 141 is in the first position and contacts a portion of the second interlock member 142 of the visible disconnect 114 to prevent the blade 121 from moving from the closed state to the open state. Specifically, the blocking portion 145 of the first interlock member 141 contacts the flat portions 147 on both sides 146 of the second interlock member 142 to prevent the blade 121 from moving from the closed state to the open state. In other words, when the first interlock member 141 is in the first position (FIG. 12A), the first interlock member 141 prevents the disconnect switch blade 121 from moving from the closed state to the open state, i.e., rotating about the pin 123. The first interlock member 142 prevents the blade 121 from opening regardless of the operating state of the visible disconnect operating mechanism 122 and actuating assemblies.

[0061] Conversely, when the contacts 119a, 119b of the vacuum interrupter 112 are open or separated (i.e., the second contact 119b is in the second position), the first interlock member 141 is in the second interlock state, and the disconnect switch blade 121 is moveable from the closed state to the open state (FIG. 14A).

[0062] When both the vacuum interrupter 112 and the blade 121 are in the open state, the disconnect switch blade 121 prevents the vacuum interrupter 112 from moving from the open state to the closed state. In particular, the curved portion 148 of second interlock member 142 is positioned to contact the beveled surface 143 of the first interlock member 141 to prevent (i.e., block) the vacuum interrupter 112 from moving from the open state to the closed state (FIG. 14A). In other words, when the vacuum interrupter 112 is in the open state and the visible disconnect 114 is in the open state, the visible disconnect 114 prevents the vacuum interrupter 112 from moving from the open state to the closed state.

[0063] Therefore, to properly open the vacuum interrupter 112 and in turn, to properly open the visible disconnect 114, an operator uses the vacuum interrupter operating assembly contained within the gearbox to move the vacuum interrupter operating mechanism 120, which changes the vacuum interrupter 112 from the closed state to the open state (i.e., moves the second contact 119b from the first position to the second position). As the vacuum interrupter operating mechanism 120 is actuated to separate the second contact 119b from the first contact 119a, the first interlock member 141 moves with the vacuum interrupter operating mechanism 120. The first interlock member 141, and specifically the blocking portion 145 of the first interlock member 141 is moved from blocking engagement with the visible disconnect 114. Then, the operator can use the visible disconnect operating assembly to actuate the visible disconnect operating mechanism 122 to open the visible disconnect 114. In the open state, the blade 121 of the visible disconnect 114 disconnects the vacuum interrupter 112 from the course conductor 124 as illustrated and provides visual verification through the viewing window 118 to an operator that the circuit is open (i.e., vacuum interrupter 112 is physically and electrically disconnected from the source conductor 124).

[0064] While both the visible disconnect 114 and the vacuum interrupter 112 are open, the second interlock member 142 is positioned to block the first interlock member 141 and as a result, block the vacuum interrupter 112 from returning to the closed position before the visible disconnect 114 is closed. To reestablish a working circuit in the switch 110 after the vacuum interrupter 112 has been opened, an operator first uses the visible disconnect operating mechanism 122 to close the visible disconnect 114. With the visible disconnect 114 in the closed state, the blade 121 of the visible disconnect 114 physically and electrically connects the vacuum interrupter 112 with the source conductor 124. After the visible disconnect 114 has been closed, the operator can use the vacuum interrupter operating mechanism 120 to close the vacuum interrupter 112 (i.e., to move the second contact 119b of the vacuum interrupter 112 from the second position to the first position). When the vacuum interrupter 112 is closed the first interlock member 141 is situated into a blocking position with the second interlock member 142, and the visible disconnect 114 cannot move to the open state using the visible disconnect operating mechanism 122.

[0065] The sequences of events defined by the interlock system 140 ensure that the visible disconnect 114 is only in the open state when the circuit is broken (i.e., when the second contact 119b is in the second position). The switch 110 maintains interlocking functionality between the disconnect switch 114 and the vacuum interrupter 112 even if there is a loss of linkages 120, 122. Assemblies are also simplified over other designs by the interlock system 140 components being integrated into the vacuum interrupter connection and disconnect switch assemblies, thus not requiring additional actuating linkage components.

[0066] Various features and advantages of the disclosure are set forth in the following claims.