Three-phase AC contactor with high switching ability

Abstract

The present invention discloses a three-phase AC contactor with high switching ability. Its contact unit includes left, middle, and right contact groups. Each contact group includes front and rear moving contacts above, front left static contact and front right static contact positioned below the front moving contact, and rear left static contact and rear right static contact positioned below the rear moving contact. The front and rear static contacts on one side are respectively connected to the normally open connection terminal and the normally closed connection terminal, and the front and rear static contacts on the other side are connected through a diversion plate, and the diversion plate is installed on the conversion connection terminal; the front and rear moving contacts of each contact group are respectively installed on the front and rear ends of the corresponding reed through the front and rear insulating contact seats, and the reed is installed on the armature driven by the electromagnetic unit; when the armature moves, one moving contact connects the two static contacts in alignment with it, and the other moving contact disconnects the two static contacts in alignment with it. The present invention adopts a double-break contact unit, which improves the switching load capacity and product reliability.

Description

Technical Field

[0001] The electronic control component of the present invention is specifically a three-phase AC contactor with high switching ability. Background Art

[0002] The large-load AC contactor is a control electrical appliance for frequently breaking or connecting a loaded circuit in an AC power transmission system. It is mainly used for remote operation and an automatic control system. In the structure of the large-load AC contactor, the main contact is used for opening and closing the circuit system or controlling the large-load circuit, and the auxiliary contact is used for transmitting control instructions.

[0003] For a large-load three-phase AC contactor with transfer contacts, its contact system usually adopts a single-break structure. Its ability to switch the load is positively correlated with the contact gap and release speed of the contact system. Usually, the method to improve the switching ability of the contactor is to increase the contact gap and contact pressure. This method requires increasing the size of the electromagnetic system to increase the electromagnetic force, which will cause the product shape to increase.

[0004] In the structure of the traditional three-phase AC contactor, the moving contact is generally riveted or welded to an elastically strainable reed. The reed is connected to the transfer terminal. When the moving and static contacts are closed, the load is conducted through the reed. When the contactor disconnects or connects a high-voltage and large-current load, the reed generates a large amount of heat and is prone to softening, resulting in the inability to break the contact, causing the contact to adhere and fail, or causing the moving contact to have a slow breaking speed and being unable to break the arc, resulting in continuous combustion of the arc and the explosion of the sealed housing. Summary of the Invention

[0005] To solve the deficiencies of the prior art, the present invention proposes a three-phase AC contactor with high switching ability.

[0006] The three-phase AC contactor with high switching ability of the invention includes a contact unit, and the differences are as follows:

[0007] 1. The contact unit includes three groups of left, middle, and right contact groups. Each contact group includes a front moving contact and a rear moving contact at the front and rear positions above, and a front left static contact, a front right static contact opposite to the front moving contact below, and a rear left static contact, a rear right static contact opposite to the rear moving contact below. The front and rear static contacts on one side (left or right) are respectively connected to the normally open terminal and the normally closed terminal of the contactor, and the front and rear static contacts on the other side (right or left) are connected through a diversion plate, and the diversion plate is installed on the transfer terminal of the contactor.

[0008] 2. The front moving contact and the rear moving contact of each contact group are respectively installed on the front and rear ends of the corresponding reed through a front insulating contact seat and a rear insulating contact seat, and the reed is installed on an armature driven by an electromagnetic unit.

[0009] 3. When the armature moves, one moving contact connects two static contacts in alignment with it, and the other moving contact disconnects two static contacts in alignment with it.

[0010] Furthermore, each moving contact is positioned and installed within a corresponding insulating contact seat and has only one degree of freedom of up-and-down movement. Along the direction of this degree of freedom, a return spring is press-fitted between the moving contact and the insulating contact seat.

[0011] When the moving contact disconnects from the two static contacts in alignment with it, under the action of the return spring, the moving contact is at the downward limit position (overtravel) in the direction of this degree of freedom. When the moving contact contacts the two static contacts in alignment with it, the return spring is further compressed to provide pressure for the moving contact.

[0012] To improve the connection reliability, the current-carrying plate is connected to the static contact by a brazing process.

[0013] To achieve good current-carrying effect and reduce heat generation under high current, the current-carrying plate is arranged on the conversion connection terminal and is fixedly connected by screws.

[0014] As a sealed three-phase AC contactor, the electromagnetic unit and the contact unit are arranged within a sealed housing.

[0015] Advantages of the present invention:

[0016] 1. In the structure of the three-phase AC contactor with high switching ability of the present invention, a double-break contact system is used to replace the traditional single-break contact system, making the sum of the contact gaps approximately twice that of the original. And due to the voltage-dividing effect of the double-break contact system, the switching load capacity and product reliability of the AC contactor are improved.

[0017] 2. In the structure of the present invention, the reed is designed not to be in the electrical circuit of the contactor, and will not heat up and soften due to abnormal connection or disconnection of the load of the contactor, avoiding the contact adhesion failure or contact abnormal arcing burnout failure caused by reed softening.

[0018] 3. The present invention improves the switching load capacity while maintaining the original product shape unchanged. Description of the Drawings

[0019] Figure 1 is a schematic structural diagram of an embodiment of the present invention.

[0020] Figure 2 is Figure 1 a side view of the embodiment.

[0021] Figure 3 is Figure 2 a top view of (only showing the static contacts in the contact group).

[0022] Figure 4 [[ID=4⑨]]isFigure 3 A-A sectional view in

[0023] Drawing number identification: 1. Front moving contact; 2. Rear moving contact; 3. Front left static contact; 4. Front right static contact; 5. Rear left static contact; 6. Rear right static contact; 7. Deflector; 8. Conversion terminal; 9. Front insulating contact seat; 10. Rear insulating contact seat; 11. Reed; 12. Armature; 13. Electromagnetic unit; 14. Return spring; 15. Screw; 16. Contact group; 17. Base. Detailed implementation mode

[0024] The technical solution of the present invention will be further described below in conjunction with the embodiments shown in the drawings.

[0025] The sealed three-phase AC contactor with high switching ability of the present invention includes an electromagnetic unit 13 and a contact unit arranged in a sealed housing. The function of the electromagnetic unit 13 is to drive the movement of the armature 12, as Figure 1 , Figure 2 shown.

[0026] The contact unit includes three groups of left, middle and right contact groups 16 (equidistantly spaced) arranged below the armature 12. The contact structure of the contact unit is equivalent to that of the original contactor in terms of space and the sum of contact pressures. Taking the left contact group 16 as an example, the structure of each contact group 16 is as follows:

[0027] The left contact group 16 includes a front moving contact 1 and a rear moving contact 2 at the upper front and rear positions. The front left static contact 3 and the front right static contact 4 are arranged on the base 17 below the front moving contact 1 in a corresponding position. The rear left static contact 5 and the rear right static contact 6 are arranged on the base 17 below the rear moving contact 2 in a corresponding position. The diameter of each moving contact is greater than the center distance of the corresponding left and right static contacts. The front left static contact 3 and the rear left static contact 5 are respectively installed at the normally open terminal (arranged on the base 17) and the normally closed terminal (on the base 17) of the contactor. The front right static contact 4 and the rear right static contact 6 are brazed to the front and rear ends of the deflector 7. The middle part of the deflector 7 is placed on the top of the conversion terminal 8 and the deflector 7 is fixed to the conversion terminal 8 with screws 15; the front moving contact 1 and the rear moving contact 2 of the left contact group 16 are respectively installed at the front and rear ends of the corresponding reed 11 through the front insulating contact seat 9 and the rear insulating contact seat 10. The middle part of the reed 11 is installed on the armature 12, as Figure 1 , Figure 2 , Figure 3 , Figure 4 shown.

[0028] The installation structure of the moving contact and the corresponding insulating contact seat is as follows: The upper end of each moving contact is positioned and installed within the corresponding insulating contact seat and has a degree of freedom for up-and-down sliding. Along the direction of this degree of freedom, a return spring 14 is press-fitted between the moving contact and the insulating contact seat. Under the action of the return spring 14, the lower end of each moving contact is at the lowest limit position, as Figure 2 shown.

[0029] The working principle of the present invention is as follows:

[0030] A double-break contact structure is adopted to replace the original single-break contact structure. The reed 11 is not in the conductive circuit of the contactor. The moving contact and two mutually insulated static contacts realize the bridge connection and disconnection functions of the load. That is, the electromagnetic unit 13 converts the input electrical signal into electromagnetic attraction to drive the armature 12. When the armature 12 moves (that is, the reed 11 drives the front insulating contact seat 9 and the rear insulating contact seat 10 to move), one moving contact connects the two static contacts in alignment with it (as Figure 1 shown, the rear moving contact 2 connects the rear left static contact 5 and the rear right static contact 6, and the return spring 14 provides contact pressure for the moving contact), and the other moving contact disconnects the two static contacts in alignment with it (as Figure 1 shown, the front moving contact 1 disconnects the front left static contact 3 and the front right static contact 4), so as to realize the conversion function of the contactor.

[0031] When the stroke of the moving contact is greater than the over-travel, that is, when the moving contact is at the lowest limit position of the downward movement, the moving contact is rigidly connected and driven by the insulating contact seat to separate from the static contact, so as to achieve the purpose of high switching ability and anti-contact adhesion; and the design of the contact pressure provided by the return spring 14 needs to fully consider the environmental indicators of the contactor to ensure that the moving contact will not shake after closing and cause contact shake-off failure.

Claims

1. A three-phase AC contactor with high switching capacity, comprising a contact unit, characterized in that: The contact unit comprises three contact groups (16) at the left, middle and right positions, each contact group (16) comprising a front moving contact (1) and a rear moving contact (2) at the upper front and rear positions, a front left static contact (3) and a front right static contact (4) positioned below the front moving contact (1), and a rear left static contact (5) and a rear right static contact (6) positioned below the rear moving contact (2), the front static contact and the rear static contact on one side being connected to the normally open terminal and the normally closed terminal of the contactor respectively, and the front static contact and the rear static contact on the other side being connected via a guide plate (7), and the guide plate (7) being mounted on the switching terminal (8) of the contactor; The front moving contact (1) and the rear moving contact (2) of each contact group (16) are respectively mounted on the front and rear ends of the corresponding spring (11) through the front insulating contact seat (9) and the rear insulating contact seat (10), and the spring (11) is mounted on the armature (12) driven by the electromagnetic unit (13); When the armature (12) moves, one movable contact connects to the two static contacts opposite to it, and the other movable contact disconnects the two static contacts opposite to it.

2. The three-phase AC contactor with high switching capability according to claim 1, characterized in that: Each movable contact is positioned and installed in a corresponding insulating contact seat and has only one degree of freedom of upward and downward movement. Along the direction of the degree of freedom, a return spring (14) is pressed between the movable contact and the insulating contact seat.

3. The three-phase AC contactor with high switching capability according to claim 2, characterized in that: When the moving contact is disconnected from the two opposite static contacts, under the action of the return spring (14), the moving contact is in the downward limit position in the direction of the degree of freedom; when the moving contact contacts the two opposite static contacts, the return spring (14) is further compressed to provide pressure for the moving contact.

4. The three-phase AC contactor with high switching capability according to any one of claims 1 to 3, characterized in that: The guide plate (7) is connected to the static contact through a brazing process.

5. The three-phase AC contactor with high switching capability according to any one of claims 1 to 3, characterized in that: The guide plate (7) is arranged on the conversion terminal (8) and is fastened with screws (15).

6. The three-phase AC contactor with high switching capability according to any one of claims 1 to 3, characterized in that: The electromagnetic unit (13) and the contact unit are arranged in a sealed housing.

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