Slot motor for improved arc mobility in circuit breaker

Abstract

An electrical switching apparatus (100) comprising a switch and an arc chamber is provided. The switch has at least one fixed contact (40) and at least one corresponding movable contact (42). The at least one movable contact (42) is movable between a contact position (200) and a separated position (240) with respect to the at least one fixed contact (40) to open and close an electrical circuit associated with the electrical switching apparatus (100). The arc chamber comprises an arc chute (50) and a slot motor. The arc chute (50) is configured in operation to confine and extinguish an arc (60) drawn within the switch as the at least one movable contact (42) moves towards the separated position (240) to open the electrical circuit. The slot motor is configured in operation to guide the arc (60) towards the arc chute (50). The slot motor comprises a first plate (10) and a second plate (12), wherein each of the first plate (10) and the second plate (12) is substantially planar and defined by a respective boundary. A first portion (13) of the boundary of the first plate (10) and a second portion of the boundary of the second plate (12) are adjacent to a first region (45), wherein the first region (45) is a space between the at least one fixed contact (40) and the at least one movable contact (42) when the at least one movable contact (42) is in the separated position (240).

Description

Slot motor for improved arc mobility in circuit breakerField

[0001] The present invention relates to electrical switching apparatus, such as, for example, circuit breakers. In particular, the present invention relates to a slot motor for use in electrical switching apparatus.Background

[0002] Electrical switching apparatus, such as circuit breakers, are employed in diverse applications relating to the provision of electrical power. One example of an electrical switching apparatus is a residual current circuit breaker with overcurrent protection (or "ROBO"). An electrical switching apparatus may include a switch with a fixed contact and a movable contact, with the movable contact being movable into and out of electrically conductive engagement with the fixed contact. This switches the electrical switching apparatus between an ON (or "closed") position and an OFF (or "open" position).

[0003] When current is flowing through an electrical system that is provided with such an example electrical switching apparatus, the separation of the movable contact from the fixed contact in order to transition the electrical switching apparatus into the open position may cause an electrical arc (or simply "arc") to be drawn between the movable contact and the fixed contact. Such an arc may compromise the safety of the electrical system and / or cause damage to the electrical switching apparatus.

[0004] Some electrical switching apparatuses are provided with means for cooling and safely extinguishing the arc.

[0005] It is desirable to provide alternative means that cool and safely extinguish the arc more effectively and / or are more cost-effective.Summary

[0006] An electrical switching apparatus is provided herein. Also provided herein is a method of cooling and / or extinguishing an arc formed with the electrical switching apparatus.

[0007] In a first aspect of the present disclosure, a system is provided in the appended independent apparatus claim, with optional features defined in the dependent claims appended thereto.The system of the first aspect is an electrical switching apparatus. The electrical switching apparatus comprising a switch and an arc chamber. The switch has atleast one fixed contact and at least one corresponding movable contact. The at least one movable contact is movable between a contact position and a separated position with respect to the at least one fixed contact to open and close an electrical circuit associated with the electrical switching apparatus. The arc chamber comprises an arc chute and a slot motor. The arc chute is configured in operation to confine and extinguish an arc drawn within the switch as the at least one movable contact moves towards the separated position to open the electrical circuit. The slot motor is configured in operation to guide the arc towards the arc chute. The slot motor comprises a first plate and a second plate, wherein each of the first plate and the second plate is substantially planar and defined by a respective boundary. A first portion of the boundary of the first plate and a second portion of the boundary of the second plate are adjacent to a first region, wherein the first region is a space between the at least one fixed contact and the at least one movable contact when the at least one movable contact is in the separated position.

[0008] In this way, the use of the electrical switching apparatus disclosed herein may result in a lower arcing time, lower material erosion within the electrical switching apparatus, and lower pressure rise within the electrical switching apparatus during operation.

[0009] In some examples, the respective boundary of each plate comprises one or more curvilinear portions. Additionally, or alternatively, the first plate may comprise a first tapered feature that increases in width away from the first region. The first tapered feature may comprise the first portion of the boundary of the first plate. Additionally, or alternatively, the second plate may comprise a second tapered feature that increases in width away from the first region. The second tapered feature may comprise the second portion of the boundary of the second plate.

[0010] In some examples, the first tapered feature comprises a protrusion having a first corner disposed directly adjacent the first region, and / or the second tapered feature comprises a protrusion having a second corner disposed directly adjacent the first region opposite the first corner of the first tapered protrusion.

[0011] In some examples at least one of the first portion of the boundary of the first plate and the second portion of the boundary of the second plate may terminate in at least one vertex.

[0012] Such tapered features and / or vertex features may facilitate an effective electromagnetic field within the electrical switching apparatus, thereby better guiding the arc towards the arc chute.

[0013] In some examples, the first plate and the second plate are on opposite sides of the first region. In this way a pervasive electromagnetic field may be provided. Additionally, or alternatively, the first plate and the second plate may be positioned between the first region and the arc chute. In this way an electromagnetic field may be provided around the first region that is directed towards the arc chute. Additionally, or alternatively, the first plate and the second plate may be substantially identical. In this way a symmetric electromagnetic field may be provided.

[0014] Such features may facilitate an electromagnetic field that more effectively guides the arc away from the first region and towards the arc chute.

[0015] In some examples, the first plate and / or the second plate may comprise ferromagnetic material, optionally magnetic steel. The high relative permeability displayed by ferromagnetic materials may facilitate the provision of electromagnetic fields required to guide the arc towards the arc chute.

[0016] In some examples, the electrical switching apparatus may further comprise a first insulating ablative plate and a second insulating ablative plate. The first insulating ablative plate may be positioned between the first plate and the first region. The second insulating ablative plate may be positioned between the second plate and the first region. In some such examples, the first insulating ablative plate and the second insulating ablative plate may formed from plastic.

[0017] In this way, the first plate and the second plate of the slot motor may be protected from conductive interaction with the arc. This may help prevent the first plate and the second plate from becoming part of a conductive path that includes the arc. In this manner, the current may be prevented from passing between the at least one fixed contact and the at least one corresponding movable contact via the first plate and / or through the second plate.

[0018] Also disclosed herein is a method of using the electrical switching apparatus of the first aspect. The method comprises: moving the at least one movable contact of the switch to open an electrical circuit associated with the electrical switching apparatus; drawing an arc within the switch as the at least one movable contact moves towards the separated position to open the electrical circuit; using the slot motor to guide the arc towards the arc chute; using the arc chute to confine and extinguish the arc.

[0019] The skilled person will recognise that the features of the system of the first aspect described above may be combined as appropriate, and that optional elements of the first aspect may also be applied to the method.Brief description of the figures

[0020] Figures 1A and IB illustrate a perspective cross-sectional view and an end cross-sectional view, respectively, of an example electrical switching apparatus.

[0021] Figure 2 illustrates a profile view of an example first plate of a slot motor.

[0022] Figures 3A-3C illustrate profile cross-sectional views of an example electrical switching apparatus in different configurations.

[0023] Figure 4 is a flowchart showing example operations for operating an example electrical switching apparatus as described herein to extinguish an arc.Detailed description

[0024] Other advantages and effects of the present disclosure will become readily apparent to those skilled in the art as the following detailed description proceeds by way of illustrative and specific examples as depicted in the Figures.

[0025] The structures, proportions, sizes, etc. shown in the drawings attached hereto are for the purpose of understanding and reading the disclosure only and are not intended to limit the scope of the disclosure in any way. For ease of description, the drawings of the present disclosure accordingly simplify or omit components commonly used in the art, which do not affect the understanding of the present disclosure by those skilled in the art.

[0026] With reference to Figures 1A-B, the present disclosure provides an electrical switching apparatus 100.

[0027] The electrical switching apparatus 100 comprises a switch having at least one fixed contact 40 and at least one corresponding movable contact 42. The at least one movable contact 42 is movable between a contact position and a separated position with respect to the at least one fixed contact 40 to open and close an electrical circuit associated with the electrical switching apparatus 100. In the example depicted in Figure 1, there is only one fixed contact 40 and one movable contact 42. However, in other examples, there may be a plurality of fixed contacts 40 and a corresponding plurality of movable contacts 42.

[0028] The electrical switching apparatus 100 may be a residual current circuit breaker with overcurrent protection (or "RCBO"). The RCBO may comprise a residual current device and a miniature circuit breaker. The former protects the user from sustaining an electric shock, while the latter protects the apparatus from short circuits and overloads.

[0029] As discussed above, the electrical switching apparatus 100 is configured to open and close an associated electrical circuit by separating the at least one movable contact 42 away from the at least one fixed contact 40.

[0030] In the example depicted in Figure 1, the electrical switching apparatus 100 is in a configuration in which the at least one movable contact 42 is in the separated position.

[0031] In the separated position, a first region 45 forms with the switch. The first region 45 is a space between the at least one fixed contact 40 and the at least one movable contact 42 when the at least one movable contact 42 is in the separated position 240.

[0032] In operation, as the at least one movable contact 42 moves away from the at least one fixed contact 40 towards the separated position 240, an arc may form within the switch. The arc is most likely to form in high voltage settings. The arc is an electrical current through an otherwise nonconductive medium such as air.

[0033] The electrical switching apparatus 100 comprises an arc chamber. An arc chamber may be a space in the proximity of the switch. The arc chamber may be designed to cool and safely extinguish the arc drawn within the switch as the at least one movable contact 42 moves from the contact position to the separated position with respect to the at least one fixed contact 40. The arc chamber comprises an arc chute 50 and a slot motor.

[0034] The arc chute 50 is configured in operation to confine and extinguish the arc drawn within the switch as the at least one movable contact 42 moves towards the separated position to open the electrical circuit. The arc chute 50 may comprise a set of insulating barriers ("splitting plates") arranged to confine and extinguish the arc.

[0035] The slot motor is configured in operation to guide the arc towards the arc chute 50. In some examples, the arc chamber may also include a stationary arc runner 30 and / or a jumper arc runner 32. The stationary arc runner 30 and / or a jumper arc runner 32 may be configured in operation further to guide the arc towards the arc chute 50. The stationary arc runner 30 and / or a jumper arc runner 32 may comprise electrically conductive material.

[0036] The slot motor comprises a first plate 10 and a second plate 12.

[0037] Figure 2 illustrates a profile view of an example first plate 10 and / or second plate 12 of a slot motor.

[0038] With reference to the example depicted in Figure 2, each one of the first plate 10 and the second plate 12 ("each plate") is substantially planar and defined by a respective boundary. The respective boundary of each plate may compriseone or more curvilinear portions. In the example depicted in Figure 2, the boundary of the first plate 10 includes one curved portion and nine linear portions. The boundary of the first plate 10 includes a first portion 13 and the boundary of the second plate 12 includes a second portion.

[0039] Returning to Figure 1A, the first portion 13 of the boundary of the first plate 10 and the second portion of the boundary of the second plate 12 are adjacent to the first region 45. The first plate 10 and the second plate 12 may be on opposite sides of the first region 45. This configuration, as depicted in Figure 1A, may facilitate the generation of the appropriate electromagnetic fields that guide the arc towards the arc chute 50. In other words, when viewed along a direction perpendicular to the planar surfaces of the first plate 10 or the second plate 12 when the switch is open, a boundary (or edge) of the first plate 10 and / or the second plate 12 lies directly between the movable contact 42 and the fixed contact 40.

[0040] In some examples, the first plate 10 and the second plate 12 may be positioned between the first region 45 and the arc chute 50. In such a manner the slot motor that comprises the first plate 10 and the second plate 12 may more efficiently guide the arc towards the arc chute 50.

[0041] In the example depicted in Figure 1A, the first plate 10 and the second plate 12 are substantially identical. This may enable in operation a consistent electromagnetic field to be generated by the slot motor that guides the arc towards the arc chute 50, rather than for example towards any one of the first plate 10 or the second plate 12.

[0042] The first plate 10 and the second plate 12 may comprise ferromagnetic material. Ferromagnetic materials have a relative permeability that is much greater than one. For example, the relative permeability of a ferromagnetic material may be greater than about 100. In generally, the first plate 10 and the second plate 12 may comprise material with relative permeability much greater than one. The relative permeability of the first plate 10 and the second plate 12 and / or the material that constitutes the first plate 10 and the second plate 12 is preferably greater than about 100. In such examples, the high relative permeability material (e.g. with relative permeability greater than about 100) may generate in operation a blow field on the arc. The blow field may be measured in units of milliTesla per kiloampere (mT / kA). The blow field generated by the material may increase the length of the arc towards the arc chute 50. Additionally, or alternatively, the blow field generated by the material may deflect or guide the arc towards the arc chute

[0043] In particular, the first plate 10 and the second plate 12 may comprise magnetic steel. In other examples, the first plate 10 and the second plate 12 may be formed from or comprise iron or any iron alloy.

[0044] The force generated on the arc depends on the magnetic flux density (measured in Tesla), the electrical current going through the arc, and the length of the arc. In particular, the total force acting on the arc is determined by the integral of the following differential equation along the length of the arc:

[0045] dF = I dl x dB,

[0046] where F is the force, / is the length of the arc, and B is the magnetic flux density.

[0047] The first plate 10 and the second plate 12 are shaped to improve the efficiency of the effect of the blow field. As described above, the effect of the first plate 10 and the second plate 12 in directing the arc may be generated as a result of the interaction between the arc current and the magnetically permeable material of the first plate 10 and the second plate 12. By shaping the first plate 10 and / or the second plate 12 such that the volume or bulk of material increases in a particular direction, at least in the vicinity of the first region 45, the arc current may be more efficiently directed in that direction than in slot motors having a substantially uniform density or volume of permeable material, at least in the vicinity of the first region 45. It is particularly preferable that the arc current is directed away from the region in which the arc forms and towards the arc chute 50. Therefore, the first plate 10 may be shaped such that the bulk or volume of material with high permeability increases from the first portion 13 of the boundary of the first plate 10 towards the arc chute 50, at least in the vicinity of the first region 45. Similarly, the bulk or volume of material with high permeability may increase from the second portion of the boundary of the second plate 12 towards the arc chute 50, at least in the vicinity of the first region 45. A suitable shape can be achieved by providing the first plate 10 and / or the second plate 12 with a shape having a cross-sectional area that, at least in the vicinity of the first region 45, increases in a direction pointing substantially away from the first region 45 and towards the arc chute 50. Detailed examples of suitable shapes are described in more detail below. The first plate 10 and the second plate 12 are preferably substantially identical and arranged symmetrically around the first region 45, and the combined effect of the first plate 10 and the second plate 12 having increasing volume or bulk of material in a direction from their respective boundaries, at least in the vicinity of the first region 45, towards the arc chute 50 is that of an aggregate increase in the volume of high permeability material away from the firstregion 45 towards the arc chute 50. Such features may generate a blow field having improved deflection characteristics in comparison to a slot motor having a substantially uniform density or volume of permeable material, at least in the vicinity of the first region 45, thereby increasing the running speed of the arc and helping to confine and extinguish the arc more quickly.

[0048] The electrical switching apparatus 100 may further comprise a first insulating ablative plate 20 and a second insulating ablative plate 22. As depicted in Figure IB, the first insulating ablative plate 20 may be positioned between the first plate 10 and the first region 45. The second insulating ablative plate 22 may be positioned between the second plate 12 and the first region 45. The first insulating ablative plate 20 and the second insulating ablative plate 22 may be placed symmetrically on either side of fixed contact 40 and the movable contact 42. The first insulating ablative plate 20 and the second insulating ablative plate 22 may be placed symmetrically on either side of the stationary arc runner 30.

[0049] In such examples, the first insulating ablative plate 20 and the second insulating ablative plate 22 may be formed from plastic.

[0050] The insulating ablative plates may insulate the plates of the slot motor during arcing events, so that there is no conductive interaction between the plates of the slot motor and the arc.

[0051] Returning to the example slot motor plate depicted in Figure 2, such a slot motor plate, whether used as a first plate 10 and / or as a second plate 12, may comprise further features that provide further advantages in operation.

[0052] The example first plate 10 depicted in Figure 2 comprises a first tapered feature 11 that increases in width away from the first region 45. The first tapered feature 11 may comprise the first portion 13 of the boundary of the first plate 10. The horn type design of the first tapered feature 11 depicted in Figure 2 is one particular example of such a design. In this design, the first tapered feature comprises a substantially right-angled protrusion, with the corner of the protrusion being disposed directly adjacent to the first region 45. The arc chute 50 is disposed opposite the corner of the protrusion. The tapered protrusion may comprise a corner having a different internal angle than a right-angle. Preferable, the internal angle is between 30° and 60° and, more preferably, between 40° and 50°. In general, the increase in the volume of material in the plate of the slot motor away from the first region 45 towards the arc chute 50 helps guide the arc towards the arc chute 50.

[0053] Similarly, the second plate 12 may comprise a second tapered feature that increases in width away from the first region 45. The second tapered feature may comprise the second portion of the boundary of the second plate 12.

[0054] Additionally, the first portion 13 of the boundary of the first plate 10 may terminate in at least one vertex (15, 17). And, similarly, the second portion of the boundary of the second plate 12 may terminate in at least one vertex. A vertex may be defined as a point at which two roughly linear lines meet.

[0055] Such features may allow a greater flux concentration in the center of each of the slot motor plates as compared to the edges of each of the slot motor plates. Thus, the greater magnetic flux density generates a greater electromagnetic force. The electromagnetic force pulls the arc towards the arc chute 50.

[0056] The provision of a first tapered feature 11 of the first plate 10 and / or a second tapered feature of the second plate 12 may increase the bulk or volume of material with high permeability from the first region 45 towards the arc chute 50, at least in the vicinity of the first region 45, as described above. Such features may generate a blow field having improved deflection characteristics in comparison to a slot motor having a substantially uniform density or volume of permeable material, thereby increasing the running speed of the arc and helping to confine and extinguish the arc more quickly.

[0057] Figures 3A-3C illustrate profile cross-sectional views of an example electrical switching apparatus 100 in different configurations.

[0058] Figure 3A depicts an example electrical switching apparatus 100 in a configuration in which the movable contact 42 is in the contact position 200. In this configuration the switch is said to be closed.

[0059] Figure 3C depicts the example electrical switching apparatus 100 in a configuration in which the movable contact 42 is in the separated position 240. In this configuration the switch is said to be open. The switch may be opened automatically in response to the detection of a fault current by the electrical switching apparatus 100. In other scenarios, the switch may be opened by the operator for maintenance or operational purposes.

[0060] Figure 3B depicts the example electrical switching apparatus 100 in a configuration in which the movable contact 42 is in an intermediate position 220 between the contact position 200 and the separated position 240. In such an example intermediate position 220, an arc 60 may form within the switch. Arcs may form especially in high voltage contexts.

[0061] Once the arc 60 forms, the slot motor guides the arc 60 towards the arc chute 50. This configuration in which in the first portion 13 of the boundary of the first plate 10 of the slot motor is adjacent to the first region 45 provides a more efficient guiding of the arc 60 towards the arc chute 50 than in prior examples.

[0062] In some examples, the blow field generated by the slot motor at the start running phase of the arc 60 may be as high as 112 mT / kA (milliTesla per kiloampere) at the end of the fixed contact 40 and the movable contact 42 or even higher. This translates to an increase in force of up to 11.5% as compared with some prior slot motors. Thus, the example slot motor disclosed herein may allow faster arc mobility during running phase of arc, thereby improving arc quenching speed. In general, the slot motor may produce a blow field in the range of 100 to 120 mT / kA, or 105 to 115 mT / kA, at the end of the fixed contact 40 and the movable contact 42.

[0063] Furthermore, the material volume required to form the slot motor plates in some examples may be as low as 349 mm3per plate. This translates to a decrease in the material volume required of up to 6.7% as compared with some prior slot motors, thereby increasing the cost-effectiveness of the slot motor.Moreover, reducing the size and / or weight of the slot motor may allow the slot motor to conform with size requirements and / or design limitations within the electrical switching apparatus 100. In general, the slot motor may require a material volume in the range 300-400 mm3per plate, or 340-370 mm3per plate.

[0064] Returning to Figure 3B, once the arc 60 forms, the blow field generated by the slot motor may deflect the arc 60 away from the first region 45 towards the arc chute 50. The resulting lengthening of the arc 60 may cool down the arc 60. Once the arc 60 reaches the arc chute 50, the arc chute 50 may confine and extinguish the arc 60.

[0065] Figure 4 a flowchart showing example operations for operating an example electrical switching apparatus as described herein to extinguish an arc within the electrical switching apparatus 100 having a switch and an arc chamber.

[0066] As described above, the switch comprises at least one fixed contact 40 and at least one corresponding movable contact 42. The at least one movable contact 42 is movable between a contact position 200 and a separated position 240 with respect to the at least one fixed contact 40 to open and close an electrical circuit associated with the electrical switching apparatus 100. The arc chamber comprises an arc chute 50 and a slot motor.

[0067] Operation 301 comprises moving the at least one movable contact 42 of the switch to open the electrical circuit associated with the electrical switching apparatus 100.

[0068] Operation 303 comprises drawing the arc within the switch as the at least one movable contact 42 moves towards the separated position 240 to open the electrical circuit.

[0069] Operation 305 comprises using the slot motor to guide the arc 60 towards the arc chute 50. The slot motor comprises a first plate 10 and a second plate 12. Each of the first plate 10 and the second plate 12 is substantially planar and defined by a respective boundary. A first portion 13 of the boundary of the first plate 10 and a second portion of the boundary of the second plate 12 are adjacent to a first region 45. The first region 45 is a space between the at least one fixed contact 40 and the at least one movable contact 42 when the at least one movable contact 42 is in the separated position 240.

[0070] Operation 307 comprises using the arc chute 50 to confine and extinguish the arc 60.

[0071] It should be realised that the foregoing embodiments are not to be construed as limiting and that other variations, modifications and equivalents will be evident to those skilled in the art and are intended to be encompassed by the claims unless expressly excluded by the claim language.

[0072] Moreover, the disclosure of the present application should be understood to include any novel features or any novel combination of features either explicitly or implicitly disclosed herein or in any generalisation thereof. Claims may be formulated to cover any such features and / or combination of such features derived therefrom.List of reference numerals10 first plate11 first tapered feature of the first plate12 second plate13 first portion of the boundary of the first plate 15, 17 vertex of the boundary20 first insulating ablative plate22 second insulating ablative plate30 stationary arc runner32 jumper arc runner40 fixed contact42 movable contact45 first region50 arc chute60 arc100 electrical switching apparatus200 contact position of the movable contact 220 intermediate position of the movable contact 240 separated position of the movable contact

Claims

Claims1. An electrical switching apparatus (100) comprising:a switch having at least one fixed contact (40) and at least one corresponding movable contact (42), the at least one movable contact (42) movable between a contact position (200) and a separated position (240) with respect to the at least one fixed contact (40) to open and close an electrical circuit associated with the electrical switching apparatus (100);an arc chamber, the arc chamber comprising:an arc chute (50), wherein the arc chute (50) is configured in operation to confine and extinguish an arc (60) drawn within the switch as the at least one movable contact (42) moves towards the separated position (240) to open the electrical circuit; anda slot motor, wherein the slot motor is configured in operation to guide the arc (60) towards the arc chute (50),wherein the slot motor comprises a first plate (10) and a second plate (12), wherein each of the first plate (10) and the second plate (12) is substantially planar and defined by a respective boundary and wherein a first portion (13) of the boundary of the first plate (10) and a second portion of the boundary of the second plate (12) are adjacent to a first region (45), wherein the first region (45) is a space between the at least one fixed contact (40) and the at least one movable contact (42) when the at least one movable contact (42) is in the separated position (240).

2. The electrical switching apparatus (100) of claim 1, wherein the first plate (10) comprises a first tapered feature (11) that increases in width away from the first region (45), and wherein the first tapered feature (11) comprises the first portion (13) of the boundary of the first plate (10), and / or wherein the second plate (12) comprises a second tapered feature that increases in width away from the first region (45), and wherein the second tapered feature comprises the second portion of the boundary of the second plate (12).

3. The electrical switching apparatus (100) of claim 2, wherein the first tapered feature (11) comprises a protrusion having a first corner disposed directly adjacent the first region (45), and / or the second tapered feature comprises a protrusion having a second corner disposed directly adjacent the first region (45) opposite the first corner of the first tapered protrusion.

4. The electrical switching apparatus (100) of any one of the preceding claims, wherein the first plate (10) and the second plate (12) are on opposite sides of the first region (45).

5. The electrical switching apparatus (100) of any one of the preceding claims, wherein the first plate (10) and the second plate (12) are positioned between the first region (45) and the arc chute (50).

6. The electrical switching apparatus (100) of any one of the preceding claims, wherein at least one of the first portion (13) of the boundary of the first plate (10) and the second portion of the boundary of the second plate (12) terminates in at least one vertex (15, 17).

7. The electrical switching apparatus (100) of any one of the preceding claims, wherein the first plate (10) and the second plate (12) comprise ferromagnetic material.

8. The electrical switching apparatus (100) of claim 7, wherein the first plate (10) and the second plate (12) comprise magnetic steel.

9. The electrical switching apparatus (100) of any one of the preceding claims, wherein the first plate (10) and the second plate (12) are substantially identical.

10. The electrical switching apparatus (100) of any one of the preceding claims, wherein the electrical switching apparatus (100) further comprises a first insulating ablative plate (20) and a second insulating ablative plate (22), wherein the first insulating ablative plate (20) is positioned between the first plate (10) and the first region (45), and the second insulating ablative plate (22) is positioned between the second plate (12) and the first region (45).

11. The electrical switching apparatus (100) of claim 10, wherein the first insulating ablative plate (20) and the second insulating ablative plate (22) are formed from plastic.

12. A method (300) of extinguishing an arc within an electrical switching apparatus (100) having a switch and an arc chamber,- 15 -wherein the switch comprises at least one fixed contact (40) and at least one corresponding movable contact (42), the at least one movable contact (42) movable between a contact position (200) and a separated position (240) with respect to the at least one fixed contact (40) to open and close an electrical circuit associated with the electrical switching apparatus (100), andwherein the arc chamber comprises an arc chute (50) and a slot motor, the method comprising:moving (301) the at least one movable contact (42) of the switch to open the electrical circuit associated with the electrical switching apparatus (100); drawing (303) the arc within the switch as the at least one movable contact (42) moves towards the separated position (240) to open the electrical circuit;using (305) the slot motor to guide the arc (60) towards the arc chute (50), wherein the slot motor comprises a first plate (10) and a second plate (12), wherein each of the first plate (10) and the second plate (12) is substantially planar and defined by a respective boundary and wherein a first portion (13) of the boundary of the first plate (10) and a second portion of the boundary of the second plate (12) are adjacent to a first region (45), wherein the first region (45) is a space between the at least one fixed contact (40) and the at least one movable contact (42) when the at least one movable contact (42) is in the separated position (240);using (307) the arc chute (50) to confine and extinguish the arc (60).

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