Precautions for the most popular use of frequency

Precautions for using frequency converter

physical environment

1) working temperature. Inside the frequency converter, there are high-power electronic components, which are very vulnerable to the influence of working temperature. Generally, this method requires expensive equipment, which is required to be 0 ~ 55 ℃. However, in order to ensure the safety and reliability of work, we should consider leaving room for use, and it is best to control it below 40 ℃. Visitors can enter the control box free of charge. The frequency converter should generally be installed on the upper part of the box, and strictly comply with the installation requirements in the product manual. It is absolutely not allowed to install the heating element or the element easy to heat close to the bottom of the frequency converter

2) ambient temperature. When the temperature is too high and the temperature changes greatly, condensation is easy to occur inside the frequency converter, and its insulation performance will be greatly reduced, which may even cause short-circuit accidents. If necessary, desiccant and heater must be added to the box

3) corrosive gas. If the concentration of corrosive gas in the operating environment is high, it will not only corrode the leads and printed circuit boards of components, but also accelerate the aging of plastic components and reduce the insulation performance. In this case, the control box should be made into a closed structure and ventilated

4) vibration and shock. When the control cabinet equipped with frequency converter is subjected to mechanical vibration and impact, it will cause poor electrical contact. At this time, in addition to improving the mechanical strength of the control cabinet and keeping away from vibration sources and impact sources, anti-seismic rubber pads should also be used to fix components that generate vibration, such as external and internal electromagnetic switches of the control cabinet. After the equipment has been operated for a period of time, it should be inspected and maintained

electrical environment

1) prevent electromagnetic wave interference. Due to rectification and frequency conversion during the operation of the frequency converter, a lot of interference electromagnetic waves are generated around, and these high-frequency electromagnetic waves have certain interference with nearby instruments and instruments. Therefore, the instrument and electronic system in the cabinet should use metal shell to shield the interference of the frequency converter to the instrument. All components and parts shall be reliably grounded. In addition, the wiring between electrical components, instruments and meters shall be shielded control cables, and the shielding layer shall be grounded. If electromagnetic interference is not handled well, the whole system will often fail to work, resulting in control unit failure or damage

2) prevent overvoltage at the input end. The power input of the frequency converter is often protected against overvoltage. However, if the high voltage at the input is applied for a long time, the input of the frequency converter will be damaged. Therefore, in practical application, it is necessary to verify the input voltage, single-phase or three-phase of the frequency converter and the rated voltage used by the frequency converter. Especially when the power supply voltage is extremely unstable, there should be voltage stabilizing equipment, otherwise serious consequences will be caused

grounding

proper grounding of frequency converter is an important means to improve the sensitivity of control system and suppress noise. The smaller the grounding resistance of frequency converter grounding terminal e (g), the better. The cross-sectional area of grounding wire should not be less than 2mm2, and the length should be controlled within 20m. The grounding of frequency converter must be separated from the grounding point of power equipment and cannot be grounded together. The shielding layer of the signal input line should be connected to the applied pressure of 13kne (g), and the other end must not be connected to the ground end, otherwise it will cause signal changes and fluctuations, making the system oscillate continuously. The frequency converter and the control cabinet should be electrically connected. If the actual installation is difficult, copper conductor can be used for bridging

lightning protection

in frequency converters, lightning absorption networks are generally set to prevent instantaneous lightning intrusion and damage to the frequency converter. However, in practical work, especially when the power line is introduced overhead, the absorption network of the frequency converter alone cannot meet the requirements. In areas with active lightning, this problem is particularly important. If the power supply is an overhead incoming line, install a special lightning arrester (option) for frequency conversion at the incoming line, or embed a steel pipe 20m away from the frequency converter as a special grounding protection according to the specifications. If the power supply is introduced by cable, the lightning protection system in the control room should be well prepared to prevent lightning from rushing into and damaging the equipment. Practice shows that this method can effectively solve the problem of lightning strike

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