Fusing single-point high-voltage contactor with quick disconnection function

Abstract

High voltage contactor apparatus and methods are disclosed. In a particular embodiment, the contactor includes a high voltage input terminal; a high-voltage output terminal; and a switch having a first closed position, a second closed position and an open position, the switch establishing a first high-voltage current path between the high-voltage input terminal and the high-voltage output terminal in the first closed position, and establishing a second high-voltage current path between the high-voltage input terminal and the high-voltage output terminal in the second closed position.

Description

Background Art

[0001] Electromechanical switching devices such as contactors and relays are designed to carry a certain amount of current for a specific period of time. Such devices are particularly important in electric vehicles. Typically, electric vehicles use discrete contactors and fuses for breaking and disconnecting during faults. While some contactors offer size / cost reductions for high-performance electric vehicles compared to discrete components, these products may be too expensive for low-cost electric vehicles. Summary of the invention

[0002] A device and method for a fused single-point high-voltage contactor with a fast disconnection are disclosed. In various embodiments, the contactor is a single pole double throw (SPDT) contactor with a low resistance path that optimizes the high current carrying and thermal efficiency of the primary throw, and a fusible fuse of the secondary throw is used for one-time fault clearing. The output ends of the double throw are shorted together. This provides a low-cost contactor and a fast disconnection function. The secondary throw will not be used in normal operation, but will be enabled when a fault occurs. In some variations, a pyrotechnic charge is used to actuate the secondary throw. In some variations, a cam with multiple lobes is used to actuate the secondary throw. In some variations, the latching contactor includes a hard stop that is withdrawn to allow a reset spring to pull the contactor into the secondary pole. The contactor no longer requires a sealed arc chamber. Therefore, the contactor does not rely on an arc slot and only requires a single break, which is beneficial to contact resistance. In some variations, the contactor uses a fusible fuse to clear the fault. Thanks to the SPDT switch, the problem of fuse aging is eliminated.

[0003] In a specific embodiment, a contactor is disclosed, which includes a high voltage input terminal and a high voltage output terminal. In this embodiment, the contactor also includes a switch having a first closed position, a second closed position, and an open position. The switch is in the first closed position to establish a first high voltage current path between the high voltage input terminal and the high voltage output terminal, and in the second closed position to establish a second high voltage current path between the high voltage input terminal and the high voltage output terminal.

[0004] In another specific embodiment, a method of operating a contactor is disclosed, the method comprising receiving a low voltage current through a coil of the contactor. Applying the low voltage current causes a switch in the contactor to move from an open position to a first closed position. The switch is in the first closed position to establish a first high voltage current path between a high voltage input terminal and a high voltage output terminal. The method also includes detecting a current exceeding a current threshold through a pyrotechnic element of the contactor, and causing the switch to move to a second closed position through the pyrotechnic element. In this embodiment, the switch is in the second closed position to establish a second high voltage current path between the high voltage input terminal and the high voltage output terminal.

[0005] In another embodiment, a method for operating a contactor is disclosed, the method comprising receiving a signal through a motor in the contactor to rotate a cam. The rotation of the cam causes a switch of the contactor to move between a first closed position, a second closed position, and an open position. The switch is in the first closed position to establish a first high-voltage current path between a high-voltage input terminal and a high-voltage output terminal, and in the second closed position to establish a second high-voltage current path between the high-voltage input terminal and the high-voltage output terminal.

[0006] In another embodiment, a method of operating a contactor is disclosed, the method comprising receiving a signal at an input end of the conductor, and in response to receiving the signal, causing a switch in the conductor to move between a first closed position, a second closed position, and an open position. In this embodiment, the switch establishes a first high-voltage current path between a high-voltage input terminal and a high-voltage output terminal in the first closed position, and establishes a second high-voltage current path between the high-voltage input terminal and the high-voltage output terminal in the second closed position.

[0007] The foregoing and other objects, features and advantages of the present invention will become apparent from the following more particular description of exemplary embodiments of the present invention as illustrated in the accompanying drawings, wherein like reference numerals generally refer to like parts of exemplary embodiments of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1A is a schematic diagram of an example fused single point contactor with rapid disconnection according to at least one embodiment of the present disclosure.

[0009] Figure 1B yes Figure 1A Another schematic diagram of the contactor.

[0010] Figure 1C yes Figure 1A Another schematic diagram of the contactor.

[0011] Figure 2A is a cross-sectional view of another example fused single point contactor with fast disconnect according to at least one embodiment of the present disclosure.

[0012] Figure 2B yes Figure 2A Another view of the contactor.

[0013] Figure 2C yes Figure 2A Another view of the contactor.

[0014] Figure 3A is a schematic diagram of another example fused single point contactor with fast disconnect according to at least one embodiment of the present disclosure.

[0015] Figure 3B yes Figure 3A Another schematic diagram of the contactor.

[0016] Figure 3C yes Figure 3A Another schematic diagram of the contactor.

[0017] Figure 4A is a cross-sectional view of another example fused single point contactor with fast disconnect according to at least one embodiment of the present disclosure.

[0018] Figure 4B yes Figure 2A Another view of the contactor.

[0019] Figure 4C yes Figure 2A Another view of the contactor.

[0020] Figure 5 is a flow chart of an example method of operating a fused single point contactor with fast disconnect in accordance with at least one embodiment of the present disclosure.

[0021] Figure 6 is a flow chart of an example method of operating a fused single point contactor with fast disconnect in accordance with at least one embodiment of the present disclosure.

[0022] Figure 7 is a flow chart of an example method of operating a fused single point contactor with fast disconnect in accordance with at least one embodiment of the present disclosure. DETAILED DESCRIPTION

[0023] The terms used to describe specific examples herein are not intended to limit other examples. Whenever singular forms such as "a", "an", and "the" are used, and only a single element is neither explicitly nor implicitly defined as mandatory, other examples may also use multiple elements to implement the same function. Similarly, when a function is subsequently described as being implemented using multiple elements, other examples may use a single element or processing entity to implement the same function. It should also be understood that the terms "comprises", "comprising", "includes" and / or "including" specify the presence of the features, integers, steps, operations, processes, actions, elements and / or parts when used, but do not exclude the presence or addition of one or more other features, integers, steps, operations, processes, actions, elements, parts and / or any combination thereof.

[0024] It should be understood that when an element is referred to as being "connected" or "coupled" to another element, these elements may be directly connected or coupled or may be connected or coupled through one or more intermediate elements. If two elements A and B are combined using "or", it should be understood that all possible combinations are disclosed, i.e., only A, only B, and A and B. An alternative wording for the same combination is "at least one of A and B". The same applies to combinations of more than two elements.

[0025] Therefore, although other examples are capable of various modifications and alternative forms, some specific examples thereof are shown in the figures and will be described in detail later. However, this detailed description does not limit further examples to the specific forms described. Further examples may encompass all modifications, equivalents, and alternatives falling within the scope of the present disclosure. Throughout the description of the accompanying drawings, the same reference numerals refer to the same or similar elements, which, when compared to each other, may be implemented identically or in a modified form while providing the same or similar functions.

[0026] To explain further, Figures 1A to 1C Schematic diagram of an example single-break, quick disconnect contactor 100 according to at least one embodiment of the present disclosure is shown. The example contactor 100 includes a single-pole double-throw (SPDT) switch 108 that switches a current path between two high-voltage current terminals 110, 112. Figure 2A , the switch 108 is shown in the open position, which is the default position in this example. The contactor also includes a coil 104 energized by a low voltage current through terminals 114, 116. When energized, the coil 104 actuates the switch 108 (e.g., via a plunger or actuator) to Figure 1B The first closed position shown in FIG. 1 establishes a first current path between the high voltage current terminals 110, 112. The example contactor 100 also includes an pyrotechnic charge 102 coupled to the terminals 118, 120 (S1, S2). Applying a specific high current load to the pyrotechnic charge 102 through the terminals 118, 120 will detonate the pyrotechnic charge 102, the force of which actuates the switch (e.g., via a plunger or actuator) to Figure 1C The second closed position shown in the figure disconnects the first current path and establishes a second current path between the high voltage current terminals 110 and 112. The second current path includes a fuse 106 (e.g., a melting fuse). In some examples, the nominal current rating of the fuse is seriously underestimated for rapid disconnection during state changes. When the fuse 106 is blown, the contactor 100 is in a permanent disconnected state.

[0027] To explain further, FIG. 2A to FIG. 2C A cross-sectional view of an example contactor 200 according to at least one embodiment of the present disclosure is shown. In some examples, the design of the contactor 200 complies with Figures 1A to 1CSchematic diagram of contactor 100 in FIG. Contactor 200 includes a single-pole double-throw switch in which a common high-voltage input switches between two circuits within a housing 202 of contactor 200. In some examples, housing 202 is an unsealed plastic housing, thereby reducing manufacturing costs. The outputs of the circuits are shorted together at a single high-voltage output terminal. In some examples, the high-voltage input terminal is an input bus bar 204, and the high-voltage output terminal is an output bus bar 222. In some examples, at least one bus bar is a solid bus bar. In some examples, at least one bus bar is a laminated bus bar. The SPDT switch implemented by contactor 200 includes a first closed or "open" position, an open or "closed" position, and a second closed or "open" position. High-voltage bus bars 204, 222 can be electrically coupled by a pivotable contactor link 208 (i.e., pole) that switches between two circuits. In some examples, the contactor link 208 is pivotally connected to one of the bus bars 222. Figure 2A The SPDT switch is depicted in an open position, wherein the contactor link 208 is electrically isolated from the input bus bar 204. This can be a default position. The contactor link 208 is supported by a contactor support assembly 232, which facilitates pivoting of the contactor link 208 about a pivot point 220. The contactor support assembly 232 can also include a return spring 218 coupled to a portion of the housing 202. In some examples, the return spring 218 biases the contactor support assembly 232, thereby biasing the contactor link 208 away from the input bus bar 204 and against a stop, such as Figure 2A The input busbar 204 and the contactor link 208 may include a contactor pad 206, such as Figure 2B As shown, the contactor pad 206 facilitates contact between the busbar 204 and the contactor link 208 in the first closed position. The contactor support assembly 232 may include a contactor spring 212, which is configured to be in a closed position. Figure 2B The first closed position shown biases the contactor link 208 toward the input busbar 204. In some examples, the housing 202 includes a hard stop 210 that prevents the contactor support assembly 232 from moving to the second closed position until the contactor 200 is triggered by a high current. For example, the hard stop 210 can be a shear-type hard stop that breaks or collapses in response to sufficient force, such as Figure 2C shown.

[0028] The contactor support assembly 232 is coupled to the plunger 224 disposed between the two coils 228. When the coils 228 are energized by applying current to C1, C2, the plunger 224 moves the contactor support assembly 232 between the open and first closed positions, thereby moving the contactor link 208. Each coil 228 is surrounded by a magnetic core 226, which includes a non-magnetic sleeve 234. Figure 2B The contactor 200 is shown with the switch in a first closed position. Energization of the coil 228 creates an electromagnetic field that pushes the plunger 224 upward toward the non-magnetic sleeve 234, which pulls the contactor support assembly 232 upward, thereby moving the contactor link 208 toward the bus bar 204. The contact pads 206 make contact and create a primary high-voltage current path (indicated by arrows) from the input bus bar 204 through the contactor link 208 to the output bus bar 222. A low-voltage current path (also indicated by arrows) is applied from one coil 228 to the other coil 28 to energize the coils 228.

[0029] The example contactor 200 also includes a pyrotechnic element 230. When a high current load greater than a specified current threshold (e.g., greater than 3 amps) is applied to the pyrotechnic element 230, the pyrotechnic element 230 is triggered and detonates. The force of the explosion drives the plunger 224 downward, and the plunger 224 drives the contactor support assembly 232 downward with force, which causes the contactor link 208 to break contact with the bus bar 204 (and disconnect the first current path), and further causes the contactor support assembly 230 to impact the hard stop 210, thereby cutting, breaking or collapsing the hard stop 210, such as Figure 2C In the absence of any object to stop the contactor support assembly 232 from being further pulled by the return spring 218, the return spring 218 pulls the contactor support assembly 232 and the contactor link 208 to the second closed position, in which the contactor link 208 contacts the fuse lead frame 216, as shown in FIG. Figure 2C In the second closed position, the secondary high voltage current path flows from the bus bar 204 through the fuse lead frame 216 and the fuse 214, through the contactor link 208, and reaches the bus bar 222, as shown in FIG. Figure 2C As shown. Fuse 214 can be a one-time fault clearing melting type fuse for the secondary high voltage current path. The secondary high voltage current path including fuse 214 is optimized for high current faults, while the primary high voltage current path is optimized for low resistance and thermal efficiency. In another embodiment, hard stop 210 is a retractable hard stop. In some examples of alternative embodiments, pyrotechnic element 230 can be omitted.

[0030] To explain further, FIG. 3A to FIG. 3C A schematic diagram of an example single-break quick disconnect contactor 300 is provided in accordance with at least one embodiment of the present disclosure. The example contactor 300 includes a single-pole double-throw (SPDT) switch 308 that switches a current path between two high-voltage current terminals 320, 322. Figure 3A, the switch 308 is shown in a first closed position, which is the default position in this example. In the first closed position, a first current path is established between the high voltage current terminals 320, 322. The contactor also includes a motor 304 controlled by a motor controller 306. The motor 304 rotates a cam 312 including a plurality of lobes. The position sensor 310 determines the position of the cam 312 and feeds the position back to the motor controller 306. To open the switch, the motor 304 rotates the cam 312 in a first direction until the first lobe exerts a mechanical force on the switch 308, causing the switch 308 to move to the open position, as shown. Figure 3B To move switch 308 to Figure 3C In the second closed position shown, the motor 304 rotates (in an opposite second direction) the cam 312 until the second lobe exerts a mechanical force on the switch 308, causing the switch 308 to move to the second closed position, thereby disconnecting the first current path and establishing a second current path between the high voltage current terminals 320, 322. The second lobe extends farther from the center of the cam than the first lobe. The second current path includes a fuse 316 (e.g., a melt-type fuse). In some examples, the nominal current rating of the fuse is seriously underestimated when disconnecting quickly during a state change.

[0031] To explain further, FIG. 4A to FIG. 4C A cross-sectional view of an example contactor 400 according to at least one embodiment of the present disclosure is shown. In some examples, the design of the contactor 400 conforms to FIG. 3A to FIG. 3C Schematic diagram of contactor 300 in FIG. Contactor 400 includes a single-pole double-throw switch in which a common high-voltage input switches between two circuits within a housing 402 of contactor 400. In some examples, housing 402 is an unsealed plastic housing, thereby reducing manufacturing costs. The outputs of the circuits are short-circuited together at a single high-voltage output terminal. In some examples, the high-voltage input terminal is an input bus bar 404, and the high-voltage output terminal is an output bus bar 418. In some examples, at least one bus bar is a solid bus bar. In some examples, at least one bus bar is a laminated bus bar. The SPDT switch implemented by contactor 400 includes a first closed or "open" position, an open or "closed" position, and a second closed or "open" position. High-voltage busbars 404, 418 can be electrically coupled by a pivotable contactor link 408 (i.e., pole) that switches between two circuits. In some examples, the contactor link 408 is pivotally connected to one of the bus bars 418. Figure 4AThe SPDT switch is depicted in a first closed position (a default position in this example) in which the contactor link 408 physically contacts the input bus bar 404 and is pivotally coupled to the output bus bar 418. The contactor link is supported by a contactor support assembly 432 that facilitates pivoting of the contactor link 408 about a pivot point 416. The contactor support assembly 432 may also include a return spring 410 that is coupled to a fuse 412 or a portion of the housing 402. In some examples, the return spring 410 biases the contactor support assembly 432, thereby biasing the contactor link 408 away from the input bus bar 404. The input bus bar 404 and the contactor link 408 may include a contactor pad 406 that facilitates contact between the bus bar 404 and the contactor link 408 in the first closed position.

[0032] The contactor support assembly 432 is coupled to the lifter 420, which is connected to the cam 422, which is controlled by the controller 430. The cam 422 is driven by a motor 428 (e.g., a stepper motor 428). The cam 422 includes a primary lobe 424 and a secondary lobe 426. Figure 4A As shown, in the first closed position, the lifter 420 is not engaged with the lobes 424, 426 of the cam 422, and the contact pad 406 is in contact. A primary high voltage current path (indicated by an arrow) is created from the input bus bar 404 through the contactor link 408 to the output bus bar 418. When the controller 430 receives a signal to disconnect the contactor 400, the controller 430 causes the motor 428 to rotate the cam 422 in a first direction so that the primary lobes 424 engage the lifter 420, thereby pushing the lifter 420 downward, driving the contactor support assembly 432 downward, and causing the contactor link 408 to disconnect from the input bus bar 404, as shown in FIG. Figure 4B As shown. Figure 4B When the controller 430 receives a signal indicating a high current or a current fault, the controller 430 controls the motor 428 to rotate the cam 422 in the opposite second direction, so that the secondary cam 426 engages with the lifter 420, pushes the lifter 420 downward, thereby driving the contactor support assembly 432 downward, and causing the contactor link 408 to contact the contact portion 436 of the fuse lead frame 414, placing the contactor in the second closed position, as shown in FIG. Figure 4C The secondary lobe 426 extends further from the center of the cam 422 than the primary lobe 424, so the secondary lobe pushes the contactor support assembly downward further than the disconnect position. Figure 4CIn the second closed position shown, the secondary high voltage current path flows from the input bus bar 404 through the fuse lead frame 414 and the fuse 412, through the contactor link 408, and reaches the output bus bar 418. The fuse 412 can be a one-time fault clearing melting fuse for the secondary high voltage current path. The secondary high voltage current path including the fuse 412 is optimized for high current faults, while the primary high voltage current path is optimized for low resistance and thermal efficiency.

[0033] To explain further, Figure 5 A flow chart is shown that illustrates an example method of operating a single point contactor with fast disconnect in accordance with at least one embodiment of the present disclosure. Figure 5 The method includes receiving 502 a low voltage current through a coil of a contactor, wherein applying the low voltage current causes a switch in the contactor to move from an open position to a first closed position, wherein the switch is in the first closed position to establish a first high voltage current path between a high voltage input terminal and a high voltage output terminal. In some examples, as described above with reference to Figures 1A to 1C and FIG. 2A to FIG. 2C As described above, the low voltage current is received 502 by the coil of the contactor. Figure 5 The method also includes detecting 504 a current exceeding a current threshold by a pyrotechnic element of the contactor. In some examples, as described above with reference to Figures 1A to 1C and FIG. 2A to FIG. 2C As described, the pyrotechnic element of the contactor detects 504 a current exceeding a current threshold. Figure 5 The method further includes inducing 506 the switch to move to a second closed position by the pyrotechnic element, wherein the switch is in the second closed position to establish a second high voltage current path between the high voltage input terminal and the high voltage output terminal. In some examples, as described above with reference to Figures 1A to 1C and FIG. 2A to FIG. 2C As described, the switch is induced 506 to move to the second closed position by the pyrotechnic element.

[0034] To explain further, Figure 6 A flow chart is shown that illustrates an example method of operating a single point contactor with fast disconnect in accordance with at least one embodiment of the present disclosure. Figure 6 The method includes receiving 602 a signal through a motor in a contactor to rotate a cam, wherein the rotation of the cam moves a switch of the contactor between a first closed position, a second closed position, and an open position, wherein the switch is in the first closed position to establish a first high-voltage current path between a high-voltage input terminal and a high-voltage output terminal, and is in the second closed position to establish a second high-voltage current path between the high-voltage input terminal and the high-voltage output terminal. In some examples, as described above with reference to FIG. 3A to FIG. 3C and FIG. 4A to FIG. 4C As described, a signal is received 602 by a motor in the contactor to rotate the cam. Figure 6The method also includes rotating 604 the cam by the motor to actuate the switch. In some examples, as described above with reference to FIG. 3A to FIG. 3C and FIG. 4A to FIG. 4C As described above, the cam is rotated 604 by the motor to actuate the switch.

[0035] To explain further, Figure 7 A flow chart is shown that illustrates an example method of operating a single point contactor with fast disconnect in accordance with at least one embodiment of the present disclosure. Figure 6 The method includes receiving 702 a signal at an input terminal of a conductor. In some examples, reference may be made to Figures 1A to 1C , FIG. 2A to FIG. 2C , FIG. 3A to FIG. 3C and FIG. 4A to FIG. 4C To perform receiving a signal 702 at the input end of the conductor. For example, Figure 1A In Figure C, the contactor can receive a signal at input terminal 118. FIG. 2A to FIG. 2C In the example, the signal can be received at the current input terminal C1. FIG. 3A to FIG. 3C In, the signal can be received by the motor controller 306. FIG. 4A to FIG. 4C In the example of , the signal may be a signal received by the controller 430 or a signal from the controller 430 . Figure 6 The method further includes causing a switch in the conductor to move between a first closed position, a second closed position, and an open position in response to receiving a signal, wherein the switch is in the first closed position to establish a first high-voltage current path between the high-voltage input terminal and the high-voltage output terminal, and is in the second closed position to form a second high-voltage current path between the high-voltage input terminal and the high-voltage output terminal. In some examples, as described above with reference to Figures 1A to 1C , Figure 2A To Figure C, Figure 3A To Figure C and Figure 4A As described in Figure C, the switch in the conductor is caused to move between a first closed position, a second closed position and an open position.

[0036] The flowcharts and block diagrams in the accompanying drawings illustrate possible implementation architectures, functions, and operations of systems, devices, and methods according to various embodiments of the present invention.

[0037] It can be understood from the above description that the various embodiments of the present disclosure may be modified and changed without departing from the true spirit of the present disclosure. The description in this specification is for illustrative purposes only and should not be interpreted as limiting. The scope of the present disclosure is limited only by the language of the appended claims.

Claims

1. A contactor, comprising: High voltage input terminal; High voltage output terminal; as well as A switch having a first closed position, a second closed position and an open position, wherein the switch establishes a first high-voltage current path between the high-voltage input terminal and the high-voltage output terminal in the first closed position, and establishes a second high-voltage current path between the high-voltage input terminal and the high-voltage output terminal in the second closed position.

2. The contactor according to claim 1, wherein: The switch includes a pivotable contactor link.

3. The contactor according to claim 1, further comprising: a coil capable of being coupled to a low voltage current source; as well as A plunger is provided, wherein energizing the coil by the low voltage current source causes movement of the plunger to actuate the switch to the first closed position.

4. The contactor of claim 3 further comprising a pyrotechnic element capable of being triggered by a threshold current level, wherein: Triggering of the pyrotechnic element causes movement of the plunger to actuate the switch to the second closed position.

5. The contactor according to claim 1, further comprising: a cam having a first lobe and a second lobe; a lifter engaged with the cam; a motor driving the cam to rotate; as well as A controller for the motor.

6. The contactor according to claim 5, wherein: The default position of the switch is the first closed position; wherein the lifter actuates the switch to the open position by engaging a first lobe of the cam; wherein the lifter actuates the switch to the second closed position by engaging a second lobe of the cam.

7. The contactor according to claim 6, wherein: The controller controls the motor to: rotate the cam to a first cam position in which the first lobe engages the lifter; and rotate the cam to a second cam position in which the second lobe engages the lifter.

8. The contactor according to claim 7, wherein: In response to detecting a current above a threshold level, the controller rotates the cam to the second cam position.

9. The contactor according to claim 1, wherein: In the disconnected position, there is no high voltage current path between the high voltage input terminal and the high voltage output terminal.

10. The contactor according to claim 1, wherein: The second high voltage current path between the high voltage input terminal and the high voltage output terminal includes a fuse.

11. The contactor according to claim 10, wherein: The fuse is a melting type fuse.

12. The contactor according to claim 10, wherein: The first high voltage current path between the high voltage input terminal and the high voltage output terminal does not include a fuse.

13. A contactor operating method, the method comprising: receiving a signal at an input end of the conductor; as well as In response to receiving the signal, a switch in the conductor is caused to move between a first closed position, a second closed position, and an open position, wherein the switch establishes a first high-voltage current path between the high-voltage input terminal and the high-voltage output terminal in the first closed position, and establishes a second high-voltage current path between the high-voltage output terminal and the high-voltage input terminal in the second closed position.

14. The method according to claim 13, wherein: The contractors include: a coil that can be coupled to an input end of the electrical conductor; and A plunger is provided, wherein energizing the coil by the signal causes movement of the plunger to actuate the switch to the first closed position.

15. The method according to claim 14, wherein: The contractor also includes a pyrotechnic element that can be triggered by a threshold current level, wherein triggering of the pyrotechnic element causes movement of the plunger to actuate the switch to the second closed position.

16. The method according to claim 13, wherein: The contractors also include: a cam having a first lobe and a second lobe; a lifter engaged with the cam; a motor for driving the cam to rotate; and A controller for the motor.

17. The method according to claim 16, wherein: The default position of the switch is the first closed position; wherein the lifter actuates the switch to the open position by engaging a first lobe of the cam; wherein the lifter actuates the switch to the second closed position by engaging a second lobe of the cam.

18. The method according to claim 17, wherein: The controller controls the motor to: rotate the cam to a first cam position in which the first lobe engages the lifter; and rotate the cam to a second cam position in which the second lobe engages the lifter.

19. The method according to claim 18, wherein: In response to detecting a current above a threshold level, the controller rotates the cam to the second cam position.

20. The method according to claim 13, wherein: In the disconnected position, there is no high voltage current path between the high voltage input terminal and the high voltage output terminal.

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