A capacitor discharging device for low voltage variable frequency drive maintenance

Abstract

The utility model relates to a capacitor discharging device for low voltage frequency converter maintenance belongs to low voltage frequency converter maintenance equipment technical field, the utility model discloses the technical scheme is: safety jack (4) is matched with discharge pen, and discharge pen is contacted with the positive and negative pole of frequency converter DC bus, and safety jack (4) connects discharge load (3) and pointer type DC voltmeter (2) through rectifier bridge (1). The utility model has the beneficial effects that: reduce the waiting time of self-contained capacitor discharge, avoid the damage of component or harm personal safety because of DC bus electrification, improve work efficiency and maintenance safety.

Description

Technical Field

[0001] This utility model relates to a capacitor discharge device for low-voltage frequency converter maintenance, belonging to the technical field of low-voltage frequency converter maintenance equipment. Background Technology

[0002] During inverter repair, multiple power outages and restorations are often required to verify whether the inverter has been repaired and whether it still reports faults after running. However, after each power outage, it is necessary to wait 5 to 20 minutes and use a multimeter to measure the complete discharge of its multiple series and parallel capacitors before disassembly and testing can be performed again.

[0003] Low-voltage frequency converters with voltage levels of 220V, 380V, and 690V can reach DC bus voltages of 310V, 540V, and 980V after rectification and filtering. Even after a power outage, these voltages can easily cause electric shock within a short period. Higher-power frequency converters have larger and more numerous built-in capacitors with longer discharge times. Therefore, in actual maintenance, much time is spent waiting for the frequency converter to complete its self-discharge, and the DC bus voltage needs to be measured multiple times to confirm that it has dropped to a safe voltage before any operation can be performed. Even if the bus voltage drops below DC 24V in actual operation, a short circuit between the positive and negative terminals of the DC bus can still generate significant sparks, easily damaging IGBTs or causing psychological trauma to maintenance personnel. Summary of the Invention

[0004] The purpose of this invention is to provide a capacitor discharge device for the maintenance of low-voltage frequency converters. By using a discharge load to discharge the DC bus of the frequency converter, it is compact, flexible, easy to carry, discharges quickly, is safe and reliable, and generates no sparks. It reduces the waiting time for the self-contained capacitor to discharge, avoids damage to components or personal safety hazards caused by the DC bus being energized, improves work efficiency and maintenance safety, and solves the above-mentioned problems existing in the background technology.

[0005] The technical solution of this utility model is: a capacitor discharge device for low-voltage frequency converter maintenance, comprising a rectifier bridge, a pointer DC voltmeter, a discharge load, and two safety sockets, which are respectively matched with positive and negative discharge pens. The positive and negative discharge pens are respectively in contact with the positive and negative terminals of the DC bus of the low-voltage frequency converter. The safety sockets are connected to the discharge load and the pointer DC voltmeter through the rectifier bridge to detect the capacitor discharge status in the low-voltage frequency converter.

[0006] The rectifier bridge is placed inside the box, and the rectifier bridge adopts the QL-35A bridge rectifier.

[0007] The pointer-type DC voltmeter is an 85C17 type small pointer meter with a range of DC 0-1500V.

[0008] The discharge load consists of four 230V 300W halogen tungsten G6.35 photographic light bulbs. The safety socket uses a 4mm high-voltage resistant banana plug that is compatible with multimeter probes.

[0009] The beneficial effects of this utility model are: by using a discharge load to discharge the DC bus of the frequency converter, it is compact, flexible, easy to carry, discharges quickly, is safe and reliable, and generates no sparks, reduces the waiting time for the discharge of its own capacitor, avoids damage to components or personal safety due to the DC bus being energized, and improves work efficiency and maintenance safety. Attached Figure Description

[0010] Figure 1 This is a top view of the present invention; Figure 2 This is a side view of the present invention; Figure 3 This is the circuit schematic diagram of this utility model; Figure 4 This is a top view of the actual product of this utility model; Figure 5 This is a three-dimensional view of the actual product of this utility model; In the diagram: 1. Rectifier bridge; 2. Pointer DC voltmeter; 3. Discharge load; 4. Safety jack. Detailed Implementation

[0011] To make the purpose, technical solution, and advantages of this utility model clearer, the technical solution of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described implementation cases are only a small part of this utility model, not all of them. All other implementation cases obtained by those skilled in the art based on the implementation cases of this utility model without creative effort are within the protection scope of this utility model.

[0012] A capacitor discharge device for low-voltage frequency converter maintenance includes a rectifier bridge 1, a pointer-type DC voltmeter 2, a discharge load 3, and two safety sockets 4, which are respectively matched with positive and negative discharge pens. The positive and negative discharge pens are in contact with the positive and negative terminals of the DC bus of the low-voltage frequency converter, respectively. The safety sockets 4 are connected to the discharge load 3 and the pointer-type DC voltmeter 2 through the rectifier bridge 1 to detect the capacitor discharge status in the low-voltage frequency converter.

[0013] The rectifier bridge 1 is placed inside the box, and the rectifier bridge 1 adopts a QL-35A bridge rectifier.

[0014] The pointer-type DC voltmeter 2 is an 85C17 type small pointer meter with a range of DC 0-1500V.

[0015] The discharge load 3 consists of four 230V 300W halogen tungsten G6.35 photographic light bulbs. The safety socket 4 uses a 4mm high-voltage safety banana socket that is compatible with multimeter probes.

[0016] In practical applications, rectifier bridge 1 uses a QL-35A (1600V withstand voltage, 35A rated current) bridge rectifier with reverse connection protection. To prevent electric shock, rectifier bridge 1 is placed inside the box. The pointer-type DC voltmeter 2 uses an 85C17 type small pointer meter (range DC 0-1500V). Because pointer-type DC voltmeters need to distinguish the positive and negative terminals of the DC power supply when measuring DC voltage, incorrect connection will damage the voltmeter. Therefore, when DC current passes through the rectifier bridge, it is always ensured that the positive terminal of the power supply is connected to the positive terminal of the voltmeter.

[0017] Discharge load 3 uses four 230V 300W halogen tungsten G6.35 photographic lamp bulbs connected in series to increase the withstand voltage and limit the discharge current. At the same time, the bulbs can more intuitively observe the charge on the capacitor. The bulbs will flash at the moment of discharge, and then their brightness will gradually decrease. When the brightness is zero, observe whether the DC voltmeter returns to zero to confirm whether the capacitor still has charge.

[0018] Safety socket 4 uses a 4mm high-voltage safety banana socket that is fully compatible with multimeter probes. Therefore, ordinary multimeter probes can be used directly, and multimeter probes are generally 1000V and 10A-20A.

[0019] This invention can discharge the series and parallel capacitors on the DC bus of a low-voltage frequency converter within seconds, while simultaneously displaying the real-time capacitor voltage. Once the voltage drops to a safe level, the frequency converter can then be tested, disassembled, or otherwise operated. This device is compact, flexible, and portable. The discharge pen uses 1000V withstand voltage multimeter probes, ensuring rapid, safe, and reliable discharge without sparks. This invention reduces the waiting time for the inverter's built-in capacitors to discharge during maintenance, avoids damage to components or personal safety hazards caused by a live DC bus during testing and disassembly, and reduces the need for frequent multimeter measurements of the inverter's DC bus voltage, thus improving work efficiency and maintenance safety.

Claims

1. A capacitor discharge device for low-voltage frequency converter maintenance, characterized in that: It includes a rectifier bridge (1), a pointer DC voltmeter (2), a discharge load (3), and a safety socket (4). There are two safety sockets (4), which are matched with positive and negative discharge pens respectively. The positive and negative discharge pens are in contact with the positive and negative terminals of the DC bus of the low-voltage frequency converter respectively. The safety socket (4) is connected to the discharge load (3) and the pointer DC voltmeter (2) through the rectifier bridge (1) to detect the discharge status of the capacitor in the low-voltage frequency converter.

2. The capacitor discharge device for low-voltage frequency converter maintenance according to claim 1, characterized in that: The rectifier bridge (1) is placed inside the box, and the rectifier bridge (1) adopts a QL-35A bridge rectifier.

3. A capacitor discharge device for low-voltage frequency converter maintenance according to claim 1, characterized in that: The pointer-type DC voltmeter (2) is an 85C17 type small pointer meter with a range of DC 0-1500V.

4. A capacitor discharge device for low-voltage frequency converter maintenance according to claim 1, characterized in that: The discharge load (3) consists of four 230V 300W halogen tungsten G6.35 photographic lamp bulbs.

5. A capacitor discharge device for low-voltage frequency converter maintenance according to claim 1, characterized in that: The safety socket (4) uses a 4mm high-voltage safety banana socket that is compatible with multimeter probes.

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