Short-circuit discharge device for polypropylene film capacitors

Abstract

The present invention belongs to the technical field of capacitor equipment, and relates to a short-circuit discharge device for polypropylene film capacitors, including a bottom plate, the surface of the bottom plate is fastened to a fixed bracket, a cylinder is installed on the fixed bracket, a vacuum arc extinguishing chamber is fixedly arranged on the bottom plate corresponding to the piston rod end of the cylinder, the vacuum arc extinguishing chamber is fixed to the bottom plate by a bracket provided at its tail through a fifth fixing nut, a sixth fixing nut, a seventh fixing nut and corresponding screws, and an AC contactor is fixedly arranged on the outer end of the bottom plate corresponding to the vacuum arc extinguishing chamber. The discharge device upgrades the original short-circuit discharge device with low safety and easy damage to a new short-circuit discharge device with high safety, high test accuracy, long service life, low cost and elastic contact electrodes for protecting the capacitor lead-out terminal from being crushed, so as to screen out products with hidden dangers of "false connection" between the gold spraying layer and the thickened metal area of ​​the polypropylene film in the polypropylene film capacitor, and ensure the reliability of the long-term service life of the polypropylene film capacitor.

Description

Technical Field

[0001] The invention belongs to the technical field of capacitor equipment and relates to a short-circuit discharge device for a polypropylene film capacitor. Background Art

[0002] In recent years, with the development of the economy, the market's requirements for product quality have become increasingly higher, which has posed a great challenge to the stability of the quality of polypropylene film capacitors.

[0003] The gold spraying process is a key process in the production process of polypropylene film capacitors. The gold spraying layer is connected to the thickened metal area on the polypropylene film surface of the capacitor element through the gold sprayed metal particles, and the lead wires are welded on the gold spraying layer to connect to the lead-out terminals on the capacitor end caps. Therefore, the quality of the gold spraying layer directly determines the quality of the connection between the capacitor element and the capacitor lead-out terminals, thereby affecting the quality of the polypropylene film capacitor. If the contact state between the gold spraying layer and the thickened metal area on the polypropylene film surface is poor, that is, there is a "false connection" phenomenon, the conventional AC withstand voltage test of the capacitor cannot be screened out, and the excessively high AC voltage in the test may reduce the withstand voltage of the film itself, affecting the stability of the quality of the polypropylene film capacitor product. In addition, if the capacitor with poor contact between the gold spraying layer and the thickened metal area on the polypropylene film surface is put into normal use, the contact loss of the capacitor will increase, and the heat generation will increase when the capacitor is powered on, which may easily lead to capacitor failure. The short-circuit discharge test uses a DC high-voltage power supply, which can not only effectively screen out capacitors with poor contact between the gold spraying layer and the thickened metal area on the polypropylene film surface, but also will not cause any damage to the polypropylene film surface. Therefore, short-circuit discharge test is an important means to detect the performance of polypropylene film capacitors.

[0004] At present, there are generally two types of short-circuit discharge test devices most commonly used on the market, one is a wire and the other is a copper electrode, but both of these test devices have great problems. Wire testing is unsafe and difficult to test, and copper electrodes are easy to spark and are also unsafe, and the contact state is uncertain, easy to damage, and easy to crush the capacitor lead end. In addition, since the above two test methods are both carried out in the air, it is easy to spark and weld the electrode, resulting in an uneven electrode surface. The contact resistance will be large and small during the test, which will also cause the current to be unstable during the test. Therefore, the above two test methods cannot meet the market's increasing demand for short-circuit discharge detection of polypropylene film capacitors. Summary of the invention

[0005] In view of the above problems, the present invention provides a short-circuit discharge device for a polypropylene film capacitor. The discharge device upgrades the original short-circuit discharge device with low safety and easy damage to a new short-circuit discharge device with high safety, high test accuracy, long service life, low cost and elastic contact electrodes for protecting the capacitor lead-out terminals from being crushed, so as to screen out products with hidden dangers of "false connection" between the gold spraying layer and the thickened metal area of ​​the polypropylene film in the polypropylene film capacitor, thereby ensuring the reliability of the long-term service life of the polypropylene film capacitor.

[0006] According to the technical solution of the present invention: a short-circuit discharge device for a polypropylene film capacitor, characterized in that: it includes a bottom plate, the surface of the bottom plate is fastened to a fixed bracket, a cylinder is installed on the fixed bracket, a vacuum arc extinguishing chamber is fixedly arranged on the bottom plate corresponding to the end of the piston rod of the cylinder, the vacuum arc extinguishing chamber is fixed to the bottom plate by the bracket provided at its tail through the fifth fixing nut, the sixth fixing nut, the seventh fixing nut and the corresponding screws, an AC contactor is fixedly arranged on the outer end of the bottom plate corresponding to the vacuum arc extinguishing chamber, the cylinder and the vacuum arc extinguishing chamber are fixedly engaged and connected by the internal thread of the connecting rod, and the AC contactor is connected by the eighth fixing nut and the seventh fixing nut. Nine fixing nuts and corresponding screws are fixed on the base plate, the contacts of the vacuum arc extinguishing chamber are externally connected to the first connecting wire and the second connecting wire, the fifth fixing nut is externally connected to the third connecting wire, the seventh fixing nut is externally connected to the fourth connecting wire, the other end of the fourth connecting wire is connected to the AC contactor, wherein the other end of the third connecting wire is welded with the first contact electrode, the other end of the fourth connecting wire is connected to the AC contactor, the AC contactor is also connected with the fifth connecting wire, and the other end of the fifth connecting wire is connected to the power supply; the other end of the first connecting wire is welded with the second contact electrode, and the other end of the second connecting wire is connected to the power supply.

[0007] As a further improvement of the present invention, the cylinder is fastened to the fixing bracket by means of a third fixing nut and a fourth fixing nut.

[0008] As a further improvement of the present invention, the first contact electrode and the second contact electrode have the same structure, wherein the first contact electrode includes a connecting nut, a fixed sleeve, a protective spring, and an electrode head. The protective spring is arranged in the inner hole of the fixed sleeve, and the electrode head passes through the inner hole of the protective spring. The upper end of the electrode head extends out from the hole at the top of the fixed sleeve and is fixed by locking the connecting nut. The upper end of the protective spring is pressed against the top of the fixed sleeve, and the lower end of the protective spring is pressed against the step of the motor head.

[0009] As a further improvement of the present invention, the fixing bracket is fixedly connected to the base plate by means of a first fixing nut, a second fixing nut and corresponding screws.

[0010] As a further improvement of the present invention, the waist-shaped groove on the fixing bracket is respectively fixedly connected to the base plate with the first fixing nut, the second fixing nut and the corresponding screws.

[0011] The technical effect of the present invention is that the product of the present invention is provided with a vacuum interrupter, that is, a pair of electrodes (contacts) and other parts sealed in a vacuum are used to achieve the closing or disconnection of the circuit by virtue of the excellent insulation and arc extinguishing performance of the vacuum, and the arc can be quickly extinguished and the current can be suppressed after the power supply is cut off. The vacuum interrupter replaces the wire or copper electrode design used in the existing conventional short-circuit discharge device, and its unique vacuum design makes the contact state more stable, can instantly disconnect the circuit, and is safer and more reliable.

[0012] The vacuum arc extinguishing chamber provided in the product of the present invention protects the electrode in a vacuum medium, the arc is not exposed, the vacuum degree can reach above 1.33×10-3Pa, the insulation strength is extremely high, the arc is easy to extinguish, that is, the arc extinguishing ability is strong, so there will be no sparking phenomenon, and there will be no phenomenon of electrode welding after sparking, so the contact resistance value and current value during the test are both constant values, and the test accuracy is higher. At the same time, the arc is not exposed, which can also effectively prevent the explosion accident of dust in the workshop, that is, it is safer and more reliable.

[0013] The vacuum arc extinguishing chamber provided in the product of the present invention has a long service life, and its mechanical life can reach 1.5 million times. Therefore, the short-circuit discharge device is highly reusable, which solves the disadvantages of the existing short-circuit discharge device that it is easy to damage and break, reduces the production cost, and is in line with economic benefits.

[0014] The product of the present invention is provided with an AC contactor. When the control circuit is energized, the contactor is closed, and the upper main contact connected in series with the current limiting resistor line is connected before the lower main contact, so as to suppress the inrush current. After completion, it is instantly disconnected and reset, during which the lower main contact enters normal operation, and the circuit is disconnected by the lower main contact, each performing its own duties. When the vacuum arc chamber is connected and operated, the short-circuit discharge device performs short-circuit discharge on the capacitor to be tested. At this time, the vacuum arc chamber is equivalent to a wire, and the power supply is short-circuited. At this time, excessive electric heat will be generated, and the temperature will rise rapidly, which may cause a fire. Therefore, an AC contactor is directly connected to the power supply. When the vacuum arc chamber is connected and operated, the circuit where the power supply is located is automatically disconnected to ensure the safety of the test.

[0015] The product of the present invention is provided with an elastic contact electrode, which is a combination design of a nut, a fixing sleeve, a protective spring and an electrode head, rather than a single copper electrode. The design of the protective spring on the electrode head can provide buffer protection when the contact electrode is connected to the capacitor to be measured, which can effectively prevent the terminals of the capacitor to be measured from being crushed, thereby reducing unnecessary waste caused by the crushing of the terminals of the capacitor to be measured and causing scrapping, and improving the production pass rate of polypropylene film capacitors. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the structure of the present invention.

[0017] Figure 2 for Figure 1 Top view of the .

[0018] Figure 3 It is a schematic diagram of the structure of the first contact electrode or the second contact electrode in the present invention. DETAILED DESCRIPTION

[0019] The specific implementation of the present invention will be further described below in conjunction with the accompanying drawings.

[0020] Figures 1 to 3 It includes a base plate 1, a fixed bracket 2, a cylinder 3, a vacuum arc chamber 4, an AC contactor 5, a power supply 6, a first contact electrode 7-1, a second contact electrode 7-2, a capacitor to be measured 8, a first connecting wire 9-1, a second connecting wire 9-2, a third connecting wire 9-3, a fourth connecting wire 9-4, a fifth connecting wire 9-5, a first fixing nut 10-1, a second fixing nut 10-2, a third fixing nut 10-3, a fourth fixing nut 10-4, a fifth fixing nut 10-5, a sixth fixing nut 10-6, a seventh fixing nut 10-7, an eighth fixing nut 10-8, a ninth fixing nut 10-9, a connecting nut 11, a fixing sleeve 12, a protective spring 13, an electrode head 14, etc.

[0021] like Figures 1 to 3As shown, the present invention is a short-circuit discharge device for a polypropylene film capacitor, comprising a base plate 1, the surface of the base plate 1 is fastened to a fixed bracket 2, a cylinder 3 is installed on the fixed bracket 2, a vacuum arc extinguishing chamber 4 is fixedly arranged on the base plate 1 corresponding to the piston rod end of the cylinder 3, the vacuum arc extinguishing chamber 4 is fixed to the base plate 1 by a bracket provided at its tail through a fifth fixing nut 10-5, a sixth fixing nut 10-6, a seventh fixing nut 10-7 and corresponding screws, an AC contactor 5 is fixedly arranged on the outer end of the base plate 1 corresponding to the vacuum arc extinguishing chamber 4, the cylinder 3 and the vacuum arc extinguishing chamber 4 are fixedly engaged and connected by the internal thread of the connecting rod, and the AC contactor 5 is fixed to the base plate 1 by an eighth fixing nut 10-8 and a ninth fixing nut 10-9 and corresponding screws. On the plate 1, the contacts of the vacuum arc extinguishing chamber 4 are externally connected to the first connecting wire 9-1 and the second connecting wire 9-2, the fifth fixing nut 10-5 is externally connected to the third connecting wire 9-3, the seventh fixing nut 10-7 is externally connected to the fourth connecting wire 9-4, and the other end of the fourth connecting wire 9-4 is connected to the AC contactor 5, wherein the other end of the third connecting wire 9-3 is welded with the first contact electrode 7-1, and the other end of the fourth connecting wire 9-4 is connected to the AC contactor 5, and the fifth connecting wire 9-5 is also connected to the AC contactor 5, and the other end of the fifth connecting wire 9-5 is connected to the power supply 6; the other end of the first connecting wire 9-1 is welded with the second contact electrode 7-2, and the other end of the second connecting wire 9-2 is connected to the power supply 6.

[0022] The cylinder 3 is fastened to the fixing bracket 2 through the third fixing nut 10 - 3 and the fourth fixing nut 10 - 4 .

[0023] The first contact electrode 7-1 and the second contact electrode 7-2 have the same structure, wherein the first contact electrode 7-1 includes a connecting nut 11, a fixed housing 12, a protective spring 13, and an electrode head 14. The protective spring 13 is arranged in the inner hole of the fixed housing 12, and the electrode head 14 is arranged to penetrate the inner hole of the protective spring 13. The upper end of the electrode head 14 extends out from the hole at the top of the fixed housing 12 and is locked and fixed by the connecting nut 11. The upper end of the protective spring 13 is pressed against the top of the fixed housing 12, and the lower end of the protective spring 13 is pressed against the step of the motor head 14.

[0024] The fixing bracket 2 is fixedly connected to the base plate 1 by means of a first fixing nut 10 - 1 , a second fixing nut 10 - 2 and corresponding screws.

[0025] The waist-shaped grooves on the fixing bracket 2 are respectively fixedly connected to the base plate 1 with the first fixing nut 10 - 1 , the second fixing nut 10 - 2 and corresponding screws.

Claims

1. A short-circuit discharge device for a polypropylene film capacitor, characterized in that: The invention comprises a base plate (1), the surface of the base plate (1) is fastened to a fixed bracket (2), a cylinder (3) is mounted on the fixed bracket (2), a vacuum arc extinguishing chamber (4) is fixedly arranged on the base plate (1) at the end of a piston rod corresponding to the cylinder (3), the vacuum arc extinguishing chamber (4) is fixed to the base plate (1) by a bracket provided at its tail end through a fifth fixing nut (10-5), a sixth fixing nut (10-6), a seventh fixing nut (10-7) and corresponding screws, an AC contactor (5) is fixedly arranged on the outer end of the base plate (1) corresponding to the vacuum arc extinguishing chamber (4), the cylinder (3) and the vacuum arc extinguishing chamber (4) are fixedly engaged and connected through the internal threads of a connecting rod, the AC contactor (5) is fixed to the base plate (1) through an eighth fixing nut (10-8) and a ninth fixing nut (10-9) and corresponding screws, and the vacuum arc extinguishing chamber The contact of (4) is externally connected to a first connecting wire (9-1) and a second connecting wire (9-2); the fifth fixing nut (10-5) is externally connected to a third connecting wire (9-3); the seventh fixing nut (10-7) is externally connected to a fourth connecting wire (9-4); the other end of the fourth connecting wire (9-4) is connected to an AC contactor (5); the other end of the third connecting wire (9-3) is welded with a first contact electrode (7-1); the other end of the fourth connecting wire (9-4) is connected to the AC contactor (5); the AC contactor (5) is also connected with a fifth connecting wire (9-5); the other end of the fifth connecting wire (9-5) is connected to a power source (6); the other end of the first connecting wire (9-1) is welded with a second contact electrode (7-2); the other end of the second connecting wire (9-2) is connected to a power source (6); The cylinder (3) is fastened to the fixing bracket (2) via a third fixing nut (10-3) and a fourth fixing nut (10-4); The first contact electrode (7-1) and the second contact electrode (7-2) have the same structure, wherein the first contact electrode (7-1) comprises a connecting nut (11), a fixed sleeve (12), a protective spring (13), and an electrode head (14); the protective spring (13) is arranged in the inner hole of the fixed sleeve (12); the electrode head (14) penetrates the inner hole of the protective spring (13); the upper end of the electrode head (14) protrudes from the hole at the top of the fixed sleeve (12) and is locked and fixed by the connecting nut (11); the upper end of the protective spring (13) is pressed against the top of the fixed sleeve (12); and the lower end of the protective spring (13) is pressed against the step of the electrode head (14).

2. The short-circuit discharge device for polypropylene film capacitor according to claim 1, characterized in that: The fixing bracket (2) is fixedly connected to the base plate (1) via a first fixing nut (10-1), a second fixing nut (10-2) and corresponding screws.

3. The short-circuit discharge device for polypropylene film capacitor according to claim 2, characterized in that: The waist-shaped grooves on the fixing bracket (2) are respectively fixedly connected to the base plate (1) with the first fixing nut (10-1), the second fixing nut (10-2) and corresponding screws.

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