Need to pay attention to the easy aging of small components in the drive circuit during the maintenance process of the inverter - News - Global IC Trade Starts Here Free

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Inverter maintenance technicians often encounter situations where inverter modules tend to burn out frequently. Many times, when a new module is installed after a failure, there's not much thought given to the root cause. According to the Electrical Automation Technology Network, most of the time, the issue isn't with the module itself but rather with the drive circuit. During maintenance, it's crucial to pay more attention to smaller components that are prone to aging or damage, such as capacitors, resistors, optocouplers, voltage regulators, and insulating varnish. Here's a closer look at these key components.

Optocoupler

The full name of an optocoupler is opto-isolator, also known as an optical coupler. It provides excellent isolation between input and output signals, making it widely used in various circuits. Optocouplers are one of the most versatile optoelectronic devices. The drive circuit using an optocoupler typically includes a feedback loop that detects signals from the output three-phase (Eu, Ev, Ew) and the drive signal. If an abnormality is detected in the inverter output, the optocoupler sends a high-level signal to the main board, causing the inverter to cut off the drive signal and display a "overcurrent" or "IGBT short circuit" fault. This protection mechanism is fast, which makes inverters with this design less likely to burn out their modules. However, if the drive components become unstable or aged, it can still affect the overall performance of the system.

Zener Diode

A Zener diode is a type of crystal diode that operates in the breakdown region of the PN junction, providing a stable voltage. These diodes are commonly used in voltage regulation and other electronic circuits. They are distinguished from regular diodes used for rectification or detection. Electricians may find it challenging to test Zener diodes, so it’s often best to replace them if there's any doubt. When repairing an inverter, it's important to clean the circuit board thoroughly, dry it, and then apply insulating varnish. Additionally, the aluminum foil on the radiator should be cleaned, and if the cooling fan is faulty or noisy, it should be replaced. Filter capacitors should be replaced every 8 years, usually with a 20% capacity change. All main circuit connection screws should also be tightened properly.

Insulating Varnish

Insulating varnish is a polymer-based material that cures into an insulating film under specific conditions. It's an essential insulating material used in electrical systems. Applying it during maintenance helps protect the circuit from dust and moisture. When disassembling integrated blocks, some technicians may accidentally damage them due to high soldering iron temperatures. To prevent this, placing a small piece of paper or water-soaked cloth over the IC before disassembly can help dissipate heat effectively and reduce the risk of damage.

Resistors

Resistance is the opposition a material offers to the flow of electric current. Materials with low resistance are conductors, while those with high resistance are insulators. When measuring the resistance of a capacitor, the multimeter's pointer will move depending on the capacitance value—larger capacitors cause a larger swing. It's important to discharge the capacitor before taking a second measurement by shorting its two terminals.