Failure and maintenance countermeasures of the hot

2022-08-21
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With the continuous improvement of industrial automation, the application field of frequency converter is becoming more and more extensive. Shandong Sida high tech machinery equipment Co., Ltd. is a high-tech enterprise specializing in the research, development and production of instruments such as industrial product experiment, detection and measurement control. At present, its products have been widely used in metallurgy, mining, papermaking, chemical industry, building materials, machinery In all industrial transmission fields such as power and construction, it can effectively achieve various functions such as speed regulation, energy saving, overcurrent, overvoltage, overload protection and so on

the frequency converter is mainly composed of rectifier (AC to DC), filter, inverter (DC to AC), braking unit, driving unit, detection unit, microprocessor unit, etc. Minrong frequency converter adjusts the voltage and frequency of the output power supply by switching off the internal IGBT, and provides the required power supply voltage according to the actual foaming ratio of the motor of 10-30 times, so as to achieve the purpose of energy saving and speed regulation

this is the most common fault of frequency conversion. We first eliminate the faults caused by parameter problems, such as current limitation and too short acceleration time, which may lead to overcurrent. Then we have to judge whether there is a current detection circuit problem. Take fvr-075g7s-4ex as an example, we sometimes see fvr-075g7s-4ex in Sandvik materials technology: experts in high-performance corrosion solutions will display the current on the panel when the motor is not connected. Where does the current come from? At this time, it is necessary to test whether there is a problem with its three Hall sensors

first, eliminate the faults caused by parameter problems, such as too short deceleration time and overvoltage caused by regenerative load. Then we can see whether the voltage detection circuit is faulty. Generally, the voltage sampling point of the voltage detection circuit is that after the middle DC bus is sampled (about 530v DC), it is reduced by the resistance with large resistance value, and then isolated by the optocoupler. When the voltage exceeds a certain value, it displays "5" overvoltage (this machine is displayed by the digital tube). We can see whether the resistance is oxidized and whether the optocoupler has a short circuit

first, we can check whether the voltage at the input end is low or lack of phase, and then look at the voltage detection circuit. Therefore, Jinan material experimental machine factory was built in the 1950s, and the judgment is the same as the voltage

if the temperature of the frequency converter is too high, check the ventilation of the frequency converter and whether the axial fan operates well. Some frequency converters have motor temperature detection devices to check the heat dissipation of the motor, and then we check whether the components of the detection circuit are normal

we can check whether there is a short circuit in the internal components of the frequency converter. With Yaskawa 616g545p5 as the column, whether there is a problem with the module, drive circuit and optocoupler is generally a problem with the module and drive. Replace the module and repair the drive circuit. "SC" fault will be eliminated

most of the current frequency converters have introduced the function of fast melting fault detection. In particular, high-power inverter, take LG sv030ih-4 inverter as an example. It mainly samples and detects the voltage in front of and behind the fast melting. When the fast fuse is damaged, the voltage at one end of the fast fuse will inevitably be lost. At this time, the isolation optocoupler will act and a Fu alarm will appear. Replacing the fast melt should solve the problem, especially it should be noted that before replacing the fast melt, it is necessary to judge whether there is a problem in the main circuit

incorrect use method or unreasonable setting environment are likely to cause malfunction and failure of frequency converter, or fail to meet the expected operation effect. In order to nip in the bud, it is particularly important to carefully analyze the cause of the failure in advance

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