AUTOMATIC TRANSFER SWITCH

Abstract

 An automatic transfer switch, including: a stationary contact, including a stationary arc contact point and a stationary main contact point, and configured to receive current from a power supply; a movable contact, including a movable arc contact point and a movable main contact point, being pivotally connected to a load and capable of pivoting between a closing position contacting with the stationary contact and a opening position not contacting with the stationary contact; an electric arc extinguishing chamber, including a plurality of grid pieces, and configured to eliminate an electric arc generated when the movable contact and the stationary contact are switched off, the stationary contact includes a first part and a second part which are connected at an angle, the first part is configured to receive current from a power supply, the second part is configured to be in contact with the movable contact, and an end of the second part extends to be flush with an upper edge of the grid pieces of the electric arc extinguishing chamber, and a flow direction of current in the second part of the stationary contact is approximately opposite to a flow direction of current in the movable contact, so as to provide a Lorentz force to an electric arc generated during disconnecting towards the electric arc extinguishing chamber.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of low-voltage electrical switches, in particular to an automatic transfer switch with high closing-opening performance.

BACKGROUND

[0002] Automatic transfer switch (TSE) is an important low-voltage electrical switch, which is used to supply power to important loads to ensure the continuity of power consumption. Usually, automatic transfer switches are needed in situations where power failure is not allowed, and "closing and opening" is one of the most important properties of automatic transfer switch.

[0003] When the automatic transfer switch is turned on, the movable contact will bounce, and an electric arc will be formed between the movable contact and the stationary contact, the electric arc will ablate the contacts and reduce the electrical life of the automatic transfer switch. In addition, the bounce of the movable contact will also occur in the part where it contacts the load, which will also produce an electric arc, resulting in the ablation of the contact.

[0004] When the automatic transfer switch is switched off, the electric arc will also be generated. In order to extinguish the electric arc as soon as possible, it is necessary to let the electric arc enter an electric arc extinguishing chamber including a plurality of grid pieces. After the electric arc enters the grid pieces, the electric arc is divided into a plurality of short electric arcs by the grid pieces, which makes the electric arc voltage of the total electric arc rise sharply to help extinguish the electric arc.

[0005] However, in the existing art, the contact between the movable contact and the stationary contact, and between the movable contact and the load is unstable, which makes the movable contact easily bounce during turning on and turning off and generates an electric arc that ablates the contact. In addition, the automatic transfer switch in the existing art cannot effectively introduce the electric arc into the electric arc extinguishing chamber to extinguish the electric arc as soon as possible, which further aggravates the ablation of the contact by the electric arc and reduces the electrical life of the switch.

SUMMARY

[0006] Therefore, it is an object of the present disclosure to provide an automatic transfer switch with high closing-opening performance that can at least partially solve the above problems, and it is expected to prolong the electrical life of the switch.

[0007] The automatic transfer switch according to the present disclosure includes: a stationary contact, including a stationary arc contact point and a stationary main contact point, and configured to receive current from a power supply; a movable contact, including a movable arc contact point and a movable main contact point, being pivotally connected to a load and capable of pivoting between a closing position contacting with the stationary contact and a opening position not contacting with the stationary contact; an electric arc extinguishing chamber, including a plurality of grid pieces, and configured to eliminate an electric arc generated when the movable contact and the stationary contact are switched off, the stationary contact includes a first part and a second part which are connected at an angle, the first part is configured to receive current from a power supply, the second part is configured to be in contact with the movable contact, and an end of the second part extends to be flush with an upper edge of the grid pieces of the electric arc extinguishing chamber, and a flow direction of current in the second part of the stationary contact is approximately opposite to a flow direction of current in the movable contact, so as to provide a Lorentz force to an electric arc generated during disconnecting towards the electric arc extinguishing chamber.

[0008] According to a preferable embodiment of the present disclosure, a flow direction of current in the first part is substantially opposite to a flow direction of current in the second part.

[0009] According to a preferable embodiment of the present disclosure, the first part includes a first section and a second section, and the second part includes a third section and a fourth section, the first section, the second section, the third section and the fourth section are connected in sequence, an obtuse angle is formed between the first section and the second section, an obtuse angle is formed between the third section and the fourth section, and a right angle is formed between the second section and the third section, and the stationary contact forms a hook-shaped structure.

[0010] According to a preferable embodiment of the present disclosure, the automatic transfer switch further includes a shield piece, the shield piece is attached to a side of the first section facing the movable contact and the electric arc extinguishing chamber.

[0011] According to a preferable embodiment of the present disclosure, the movable contact includes two movable main contact points.

[0012] According to a preferable embodiment of the present disclosure, the movable arc contact point of the movable contact is closer to an end of the movable contact than the movable main contact point, so that the movable arc contact point firstly contacts the stationary contact before the movable main contact point when connecting, and the movable arc contact point of the movable contact contacts the stationary arc contact point of the stationary contact and the movable main contact point of the movable contact contacts the stationary main contact point of the stationary contact when connecting.

[0013] According to a preferable embodiment of the present disclosure, the movable arc contact point includes a first movable arc contact part and a second movable arc contact part, the first movable arc contact part includes a first branch and a second branch, and the second movable arc contact part includes a third branch and a fourth branch, the first branch and the second branch form an L-shape, and the third branch and the fourth branch form an L-shape, and the first branch is arranged on a side surface of a movable contact body and contacts the movable contact body, the second branch is fixed to a main surface of the movable contact body, the third branch is fixed to a main surface of the movable contact body, the fourth branch is arranged on another side of the movable contact body opposite to a side surface contacting with the first branch, and a gap is formed between the second branch and the third branch.

[0014] According to a preferable embodiment of the present disclosure, the automatic transfer switch includes N movable contacts and N/2 stationary contacts (N is an even number greater than or equal to 2), each stationary contact and two corresponding movable contacts form a group, and the two movable contacts in each group contact both sides of a corresponding stationary contact respectively, and the gap between the two movable contacts in each group is smaller than a thickness of the corresponding stationary contact.

[0015] According to a preferable embodiment of the present disclosure, the automatic transfer switch further includes a first spring piece fixed to the stationary contact, the first spring piece includes a leg extending towards the movable contact, so that the stationary arc contact point firstly contacts the movable arc contact point when connecting, then the leg of the first spring piece contacts a secondary surface of the movable contact, and finally the stationary main contact point contacts the movable main contact point.

[0016] According to a preferable embodiment of the present disclosure, the automatic transfer switch further includes a second spring piece fixed to the load, the second spring piece is in contact with a secondary surface of a corresponding movable contact.

BRIEF DESCRIPTION OF DRAWINGS

[0017] 

Fig. 1 shows a schematic diagram of an automatic transfer switch according to the present disclosure;

Fig. 2 shows a schematic diagram of an automatic transfer switch according to an embodiment of the present disclosure, in which only the stationary contact at one side is shown;

Fig. 3 shows a stationary contact of an automatic transfer switch according to an embodiment of the present disclosure;

Fig. 4 shows a movable contact of an automatic transfer switch according to an embodiment of the present disclosure;

Fig. 5 shows a schematic diagram of an automatic transfer switch according to an embodiment of the present disclosure, in which a movable contact and a stationary contact are in a closed state;

Fig. 6A shows an end view of a movable contact of an automatic transfer switch in the existing art;

Fig. 6B shows an end view of a movable contact of an automatic transfer switch according to an embodiment of the present disclosure;

Fig. 7 shows a view when the movable contact of the automatic transfer switch just comes into contact with the stationary contact in a connecting process according to an embodiment of the present disclosure;

Fig. 8A shows a view of an automatic transfer switch according to another embodiment of the present disclosure, in which an electric arc extinguishing chamber is omitted;

Fig. 8B shows another view of the automatic transfer switch of Fig. 8A;

Fig. 9 shows an automatic transfer switch provided with a first spring piece and a second spring piece;

Fig. 10 shows the structure of a first spring piece;

Fig. 11 shows the structure of a second spring piece.

DETAILED DESCRIPTION

[0018] In order to make the purpose, technical scheme and advantages of the technical solution of the present disclosure clearer, the technical solution of the embodiment of the present disclosure will be described clearly and completely in the following with the attached drawings of specific embodiments of the present disclosure. Like reference numerals in the drawings represent like parts.

[0019] Unless otherwise defined, technical terms or scientific terms used herein shall have their ordinary meanings as understood by people with ordinary skills in the field to which this invention belongs. The words "first", "second" and similar words used in the specification and claims of the patent application of the present disclosure do not indicate any order, quantity, or importance, but are only used to distinguish different components. Similarly, similar words such as "a" or "an" do not necessarily mean quantitative restrictions. Similar words such as "including" or "comprising" mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Similar words such as "connecting" or "connected" are not limited to physical or mechanical connection, but can include electrical connection, whether direct or indirect. "Up", "Down", "Left" and "Right" are only used to indicate the relative positional relationship. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0020] Hereinafter, the present disclosure will be described in detail by describing exemplary embodiments.

[0021] Fig. 1 shows a schematic diagram of an automatic transfer switch according to the present disclosure. As illustrated by Fig. 1, the automatic transfer switch 1 according to the present disclosure includes a first power supply, a second power supply, a load, a stationary contact 100, a movable contact 200 and an electric arc extinguishing chamber 300. The stationary contact 100 is connected to a power source to receive current, and the movable contact 200 is pivotally connected to a main shaft on a load, and can pivotally move around the main shaft between a closing position in contact with the stationary contact 100 and a opening position not in contact with the stationary contact 100. In Fig. 1, the movable contact 200 is in the opening position without contacting with the stationary contact 100; in Fig. 5, the movable contact 200 is connected with the stationary contact 100 and is in the closing position. The electric arc extinguishing chamber 300 includes a plurality of grid pieces 310. After the electric arc enters the electric arc extinguishing chamber 300, the electric arc is divided into a plurality of short electric arcs by the grid pieces 310, so that the electric arc voltage of the total electric arc rises sharply to extinguish the electric arc.

[0022] When the movable contact 200 rotates around the main shaft of the load, the first power supply can be connected with the load or the second power supply can be connected with the load. Because the automatic transfer switch 1 has a symmetrical structure, the automatic transfer switch 1 according to the present disclosure will be described below only by taking the closing and opening of the movable contact 200 and the stationary contact 100 at one side as an example. It should be understood that the description of the specific details about the closing and opening between the movable contact 200 and the stationary contact 100 at one side can also be applied to the stationary contact at the other side.

[0023] As can be seen from Fig. 2, the stationary contact 100 is roughly hook-shaped, and consists of a first part 110 close to the power supply side and a second part 120 close to and in contact with the movable contact 200. The first part 110 and the second part 120 are connected at an angle, and the connection is approximately at a right angle. The first part 110 includes a first section 111 and a second section 112, and an obtuse angle is formed between the first section 111 and the second section 112. The second part 120 includes a third section 121 and a fourth section 122, and an obtuse angle is formed between the third section 121 and the fourth section 122. The first section 111, the second section 112, the third section 121 and the fourth section 122 are connected in sequence, a right angle is formed between the second section 112 and the third section 121. The arrow in Fig. 2 shows the flow direction of current. As can be seen from the figure, the flow direction of current in the first section 111 and the second section 112 is generally downward, and the flow direction in the third section 121 and the fourth section 122 is generally upward, so the flow direction of current in the first section 110 is generally opposite to that in the second section 120.

[0024] As illustrated by Fig. 2, the current in the stationary contact 100 is divided into five parts: A, B, C, D, and E, in which the currents of parts A and B are located in the first section 111, current of part C is located in the second section 112, current of part D is located in the third section 121, and current of part E is located in the fourth section 122. The current in the movable contact 200 is part F, and the current in the load is part G. Upon disconnecting, an electric arc is generated between the stationary contact 100 and the movable contact 200, that is, an electric arc is generated between the part E and the part F. According to the flow directions of the currents of every parts in the figure, it can be seen that the Lorentz force generated by the current in parts A, B and C is downward, which prevents the electric arc from entering the electric arc extinguishing chamber 300; however, the Lorentz force generated by the current in parts D, E and F is upward, which urges the electric arc to enter the electric arc extinguishing chamber 300.

[0025] Therefore, in order to enhance magnetic blowing, it is preferable to weaken the influence of currents in parts A, B and C on electric arc generation. Because the currents in parts A and C are away from the electric arc, it is mainly needed to shield the magnetic field generated by the current in part B. Preferably, the stationary contact 100 is provided with a shield piece 101, such as ferromagnetic material, the shield piece 101 is arranged on a side of the first section 111 of the stationary contact 100 facing the movable contact 200 and the electric arc extinguishing chamber 300. In other words, the shield piece 101 is arranged in a chamber surrounded by four parts of the hook-shaped stationary contact 100, and is used for shielding the magnetic field generated by the current flowing downwards in the first part 110 of the stationary contact 100, so as to weaken the Lorentz force generated by the magnetic field on the electric arc to prevent it from entering the electric arc extinguishing chamber 300.

[0026] In the preferred embodiment of the present disclosure, the fourth section 122 extends towards a direction of the first section 111 (the upper left direction in Fig. 2), and the extending part is also called an electric arc striking angle. This arrangement increases the distance between the stationary contact 100 and the movable contact 200, and the electric arc root on the stationary contact 100 moves up under the action of magnetic blowing, so that the electric arc is lengthened, which is more conducive to electric arc extinguishing. Particularly preferably, as illustrated by Fig. 2, the fourth section 122 extends upward to a position flush with an upper edge of the grid piece 310 of the electric arc extinguishing chamber 300.

[0027] In the preferred embodiment of the present disclosure, the stationary contact 100 includes a stationary arc contact point 130 and a stationary main contact point 140, which are located on the second part 120 of the stationary contact 100. As illustrated by Fig. 3, the stationary main contact point 140 is a portion of the stationary contact circled by a dotted line. Accordingly, the movable contact 200 includes a movable arc contact point and a movable main contact point, and preferably includes two movable main contact points, namely a first movable main contact point 221 and a second movable main contact point 222. As illustrated by Fig. 4, the movable arc contact point 210 is fixed to the end of the movable contact main body 230 of the movable contact 200, and two movable main contact points 221 and 222 are parts of the movable contact main body 230, which are arranged side by side next to the movable arc contact point 210. Preferably, the two movable main contact points 221 and 222 are both spherical surfaces. For the convenience of description, in this paper, the side where the first movable main contact point 221 and the second movable main contact point 222 are located (that is, the side where the movable contact 200 contacts the stationary contact 100) is called the main surface of the movable contact 200 and the movable contact body 230, and the side of the movable contact 200 (and thus the movable contact body 230) opposite to the main surface is called the secondary surface.

[0028] Fig. 5 shows a view of the movable contact 200 and the stationary contact 100 after closing. As can be seen from the figure, when the movable contact and the stationary contact are connected, the stationary arc contact point 130 of the stationary contact 100 is in contact with the movable arc contact point 210 of the movable contact, and the stationary main contact point 140 of the stationary contact 100 is in contact with the movable main contact points 221 and 222 of the movable contact 200. In the existing art, usually each power supply only uses one movable main contact point of the movable contact, and the other movable main contact point is not in contact with the stationary contact. However, in the preferred embodiment of the present disclosure, the two main movable contact points 221 and 222 of the movable contact 200 are both in contact with the stationary contact 100, and the movable contact 200 has three contact points on the stationary contact 100 and the load, and the point of contact pressure falls inside the triangle formed by the contact points of the two main movable contact points 221 and 222 and the stationary contact 100 and the contact point of the movable contact 200 and the load, so that when being connected, the contact between the movable contact 200 and the stationary contact 100 and the contact between the moveable contact 200 and the load are more stable. The double contact points can be used as a redundant design. After the switch being used for a certain number of years, the closing angle (angle α in Fig. 5) will become smaller and smaller due to the wear and deformation of the driving parts (such as the operating mechanism used to drive the movable contact) and transmission parts, which may lead to the decline of the switch performance, but the switch will not completely fail because there is still one contact point being connected. In addition, the design that the two movable main contact points 221 and 222 are connected at the same time can reduce the contact resistance, which is beneficial to reduce the temperature rise.

[0029] Figs. 6A and 6B are end views of the movable contact, showing the detailed structure of the movable arc contact, Fig. 6A shows the movable arc contact point in the existing art, and Fig. 6B shows the improved movable arc contact point according to the present disclosure. As illustrated by Fig. 6A, the movable arc contact point 210 in the existing art is a one-piece structure, which covers a main surface of the movable contact main body 230 of the movable contact 200 and the parts close to the end of two side surfaces, and is welded to the main surface of the movable contact main body 230, and the welding surface is shown by a thick dotted line. As can be seen from Fig. 6A, there is a gap between the movable arc contact point 210 and the two side surfaces of the movable contact body 230 in the existing art, that is, the two sides of the movable arc contact point 210 are cantilever. However, because the side surface of the movable contact 200 contacts the stationary contact 100 at the time of connecting, the cantilever part of the movable arc contact point 210 is impacted, so the corner of the movable arc contact point 210 (the position indicated by the arrow in Fig. 6A) is easy to break.

[0030] In order to solve the above problems, the movable arc contact point according to the present disclosure is changed from a one-piece structure to a two-piece structure. As illustrated by Fig. 6B, the movable arc contact point 210 includes a first movable arc contact part 211 and a second movable arc contact part 212, and the two movable arc contact parts 211 and 212 are preferably symmetrical. The first movable arc contact part 211 includes a first branch 2111 and a second branch 2112, which form an L-shape. The second movable arc contact part 212 includes a third branch 2121 and a fourth branch 2122, which form an L-shape. The first movable arc contact part 211 is fixed to the movable contact body 230 via the welding of the first branch 2111 with the main surface of the movable contact body 230, and the welding surface is shown by the thick dotted line; the second movable arc contact part 212 is fixed to the movable contact body 230 via the welding of the third branch 2121 to the main surface of the movable contact body 230, and the welding surface is shown by the thick dotted line. Different from the existing art structure shown in Fig. 6A, the improved movable arc contact point 210 according to the present disclosure is closely attached to two side surfaces of the movable contact body 230. Specifically, the first branch 2111 of the movable arc contact point 210 contacts one side surface of the movable contact body 230, and the fourth branch 2122 contacts the side surface opposite to the side surface contacting the first branch 2111 of the movable contact body 230. In this way, the inner side of the L-shaped structure of the two movable arc contact parts 211 and 212 are completely attached to the movable contact main body 230, and there is no cantilever structure as illustrated by Fig. 6A on both sides of the movable arc contact point 210, so the rigidity of the movable arc contact point 210 is greatly improved, and it is not easy to break under the impact of connecting. In addition, as illustrated by Fig. 6B, a certain gap remains between the two movable arc contact parts 211 and 212 (i.e., between the second branch 2112 and the third branch 2121).

[0031] Fig. 7 shows the view when the movable contact 200 just contacts the stationary contact 100 during the connecting process. Combining with the opening state of Fig. 2, the just-contacted state of Fig. 7 and the closing state of Fig. 5, it can be seen that, during connecting, the movable arc contact point 210 of the movable contact 200 first contacts the stationary arc contact point 130 of the stationary contact 100, and then the movable contact 200 is connected with the main contact point of the stationary contact 100, so the impact force of connecting mainly acts on the movable arc contact point 210 and the stationary arc contact point 130; when opening the brake, the main contact of the movable contact 200 and the stationary contact 100 is disconnected first, and then the movable arc contact point 210 and the stationary arc contact point 130 are disconnected.

[0032] Preferably, both the stationary arc contact point 130 and the movable arc contact point 210 are made of high melting point alloy material and welded on the contact substrate. When connecting, the movable contact 200 and the stationary contact 100 will bounce at the moment of contacting, and the generated arc will be carried by the movable arc contact point 210 and the stationary arc contact point 130. The electric arc generated during disconnecting is also carried by the movable arc contact point 210 and the stationary arc contact point 130. The arc contact point made of high melting point alloy material can protect the main contact point with low melting point from electric arc ablation and ensure that the arc contact point can still maintain good size and shape after repeated ablation.

[0033] According to the preferred embodiment of the present disclosure, a plurality of groups of stationary contacts and movable contacts are provided for the automatic transfer switch, thus forming a multi-loop parallel structure. As illustrated by Figs. 8A and 8B, the automatic transfer switch 1 includes two stationary contacts and four movable contacts, each stationary contact corresponds to two movable contacts. Take a group of stationary contact and movable contacts on the left side as an example. Both sides of the hook-shaped structure of the stationary contact 100 are provided with a stationary arc contact point 130 made of high melting point alloy material. The first movable contact 200a in this group contacts the stationary contact 100 from the left side, and the second movable contact 200b contacts the stationary contact 100 from the right side. The gap between the first movable contact 200a and the second movable contact 200b is preferably slightly smaller than the thickness of the stationary contact 100, so that the opening between the first movable contact 200a and the second movable contact 200b is opened by the stationary contact 100 when connecting, in other words, two movable contacts 200a and 200b in the same group clamp the stationary contact 100 from both sides, which makes the contact between the movable contact and the stationary contact more stable. Preferably, as illustrated by Figs. 7 and 9, a contact spring 240 is also provided on the secondary surface of the movable contact, so that when connecting, the contact spring 240 biases the movable contact 200 toward the stationary contact 100 and the load, and prevents the bounces between the movable contact 200 and the stationary contact 100 (and between the movable contact 200 and the load) to generate an unexpected electric arc.

[0034] The four movable contacts in Figs. 8A and 8B divide the large current flowing through the switch into four small currents, and correspondingly, when disconnecting, the electric arc is also divided into four. The smaller current is easier to break, and the four arcs are carried by four groups of arc contact points, which reduces the ablation degree of the contacts and is beneficial to improve the electrical life of the switch. It should be understood by those skilled in the art that the automatic transfer switch including two stationary contacts and four movable contacts shown in the figure is only an example, and any number of contact groups can be provided for the automatic transfer switch according to needs, that is, the automatic transfer switch can include N movable contacts and N/2 stationary contacts (N is an even number greater than or equal to 2), each stationary contact and two corresponding movable contacts form one group, and two movable contacts in each group respectively contact both sides of the corresponding stationary contact.

[0035] Particularly preferably, an auxiliary circuit can also be provided for the automatic transfer switch of the present disclosure to eliminate the electric arc generated by bouncing between the movable contact and the stationary contact during connecting. As illustrated by Fig. 9, the automatic transfer switch 1 may further include a first spring piece 400, the specific structure of which is shown in Fig. 10. The first spring piece 400 includes a fixing part 410 for fixing to the stationary contact 100 and a plurality of legs 420 extending from the fixing part 410 toward the movable contact. As can be seen from the figure, in the connecting process, the movable arc contact point 210 of the movable contact 200 first contacts the stationary arc contact point 130 of the stationary contact 100, then the leg 420 of the first spring piece 400 contacts the secondary surface of the movable contact body 230, and finally the first movable main contact point 221 and the second movable main contact point 222 of the movable contact 200 contact the stationary main contact point 140 of the stationary contact 100. Without the first spring piece 400, the contact of movable arc contact point and the stationary arc contact point and the contact of movable main contact point and the stationary main contact point will bounce, and the bounce of main contact point will generate an electric arc and cause the contact to be ablated by electric arc. After the first spring piece 400 is provided, even if there is bounce between the movable contact and stationary contact, current can still be conducted by the auxiliary loop formed between the first spring piece 400 and the secondary surface of the movable contact body 230, which can eliminate arcing caused by contact bounce. Those skilled in the art can imagine that the structure of the first spring piece 400 is not limited to this, and a plurality of legs 420 need not be fixed to the stationary contact 100 via the unified fixing part 410, but each leg 420 can be fixed to the stationary contact 100 separately.

[0036] Similarly, a similar second spring piece 500 can also be arranged on the load, and its specific structure is shown in Fig. 11. As illustrated by Fig. 11, one end of the second spring piece 500 is fixedly connected to the load, and the other end is always pressed against the secondary surface of the movable contact body 230. After setting the second spring piece 500, even if the movable contact 200 bounces with the load, the current can still be conducted by the auxiliary loop formed between the second spring piece 500 and the secondary surface of the movable contact body 230, so as to eliminate arcing caused by the contact bouncing. Compared with the switch without auxiliary circuit, the connecting performance (connecting times) of the switch with auxiliary circuit can be improved by 5-10 times, which greatly prolongs the electrical life of the switch.

[0037] In this paper, several exemplary embodiments of the improved automatic transfer switch according to the present disclosure are described in detail with reference to preferred embodiments. However, those skilled in the art can understand that various variations and modifications can be made to the above specific embodiments without departing from the concept of the present disclosure, and various technical features and structures proposed by the present disclosure can be combined without exceeding the scope of protection of the present disclosure, which is determined by the appended claims.

Claims

1. An automatic transfer switch, comprising:

a stationary contact, comprising a stationary arc contact point and a stationary main contact point, and configured to receive current from a power supply,

a movable contact, comprising a movable arc contact point and a movable main contact point, being pivotally connected to a load and capable of pivoting between a closing position contacting with the stationary contact and a opening position not contacting with the stationary contact,

an electric arc extinguishing chamber, comprising a plurality of grid pieces, and configured to eliminate an electric arc generated when the movable contact and the stationary contact are switched off,

wherein, the stationary contact comprises a first part and a second part which are connected at an angle, the first part is configured to receive current from a power supply, the second part is configured to be in contact with the movable contact, and an end of the second part extends to be flush with an upper edge of the grid pieces of the electric arc extinguishing chamber, and a flow direction of current in the second part of the stationary contact is approximately opposite to a flow direction of current in the movable contact, so as to provide a Lorentz force to an electric arc generated during disconnecting towards the electric arc extinguishing chamber.

2. The automatic transfer switch according to claim 1, wherein a flow direction of current in the first part is substantially opposite to a flow direction of current in the second part.

3. The automatic transfer switch according to claim 2, wherein the first part includes a first section and a second section, and the second part includes a third section and a fourth section, the first section, the second section, the third section and the fourth section are connected in sequence, an obtuse angle is formed between the first section and the second section, an obtuse angle is formed between the third section and the fourth section, and a right angle is formed between the second section and the third section, and the stationary contact forms a hook-shaped structure.

4. The automatic transfer switch according to claim 3, further comprising a shield piece, wherein the shield piece is attached to a side of the first section facing the movable contact and the electric arc extinguishing chamber.

5. The automatic transfer switch according to claim 1, wherein the movable contact comprises two movable main contact points.

6. The automatic transfer switch according to claim 5, wherein the movable arc contact point of the movable contact is closer to an end of the movable contact than the movable main contact point, so that the movable arc contact point contacts the stationary contact before the movable main conta ct point when closing, and the movable arc contact point of the movable conta ct contacts the stationary arc contact point of the stationary contact and the movable main contact point of the movable contact contacts the stationary main contact point of the stationary contact after connecting.

7. The automatic transfer switch according to claim 6, wherein the movable arc contact point comprises a first movable arc contact part and a second movable arc contact part, the first movable arc contact part comprises a first branch and a second branch, and the second movable arc contact part comprises a third branch and a fourth branch, the first branch and the second branch form an L-shape, and the third branch and the fourth branch form an L-shape, and the first branch is arranged on a side surface of a movable contact body and contacts the movable contact body, the second branch is fixed to a main surface of the movable contact body, the third branch is fixed to a main surface of the movable contact body, the fourth branch is arranged on another side of the movable contact body opposite to a side surface contacting with the first branch, and a gap is formed between the second branch and the third branch.

8. The automatic transfer switch according to claim 1, wherein the automatic transfer switch comprises N movable contacts and N/2 stationary contacts (N is an even number greater than or equal to 2), each stationary contact and two corresponding movable contacts form a group, and the two movable contacts in each group contact both sides of a corresponding stationary contact respectively, and the gap between the two movable contacts in each group is smaller than a thickness of the corresponding stationary contact.

9. The automatic transfer switch according to claim 1, further comprising a first spring piece fixed to the stationary contact, wherein the first spring piece comprises a leg extending towards the movable contact, so that the stationary arc contact point firstly contacts the movable arc contact point when connecting, then the leg of the first spring piece contacts a secondary surface of the movable contact, and finally the stationary main contact point contacts the movable main contact point.

10. The automatic transfer switch according to claim 1, further comprising a second spring piece fixed to the load, wherein the second spring piece is in contact with a secondary surface of a corresponding movable contact.

Drawing