2) Working temperature. Inverter is a high-power electronic component, which is easily affected by working temperature. Generally, the product is required to be 0 ~ 55℃, but in order to ensure safe and reliable operation, it should be considered to leave room when using, and it is best to control it below 40℃. In the control box, the frequency converter should generally be installed at the upper part of the box, and the installation requirements in the product manual should be strictly observed. It is absolutely not allowed to install heating elements or easily heating elements near the bottom of the frequency converter.
3) corrosive gas. If the concentration of corrosive gas is high, it will not only corrode component leads, printed circuit boards, etc. It will also accelerate the aging of plastic devices and reduce the insulation performance. In this case, the control box should be made into a closed structure and ventilated.
4) Vibration and impact. 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 the electromagnetic switches and other components that generate vibration outside and inside the control cabinet. After the equipment has been running for a period of time, it should be inspected and maintained.
Electrical environment
1) to prevent electromagnetic interference. Due to the rectification and frequency conversion during the operation of the inverter, a large number of interference electromagnetic waves are generated around it, and these high-frequency electromagnetic waves have certain interference to nearby instruments and meters. Therefore, the instrument and electronic system in the cabinet should adopt metal shell to shield the interference of frequency converter to the instrument. All components shall be reliably grounded. In addition, shielded control cables should be used for wiring between electrical components and instruments, and the shielding layer should be grounded. If the electromagnetic interference is not handled well, it will often make the whole system unable to work, resulting in the failure or damage of the control unit. For details, please visit: transmission and distribution equipment network.
2) Prevent input overvoltage. The input of inverter power supply often has overvoltage protection, but if the high voltage at the input terminal acts for a long time, it will damage the input of inverter. Therefore, in practical application, it is necessary to check the input voltage, single-phase or three-phase and rated voltage of the inverter. Especially in the case of extremely unstable power supply voltage, it is necessary to have voltage stabilizing equipment, otherwise it will cause serious consequences.
Correct grounding of frequency converter is an important means to improve the sensitivity of control system and suppress noise. The smaller the grounding resistance of the inverter grounding terminal E(G), the better. The cross-sectional area of grounding conductor shall be no less than 2mm2, and the length shall be controlled within 20m. The grounding of frequency converter must be separated from the grounding point of power supply equipment, and it cannot be * * *. The shielding layer of the signal input line should be connected to E(G), and the other end should never be grounded, otherwise it will cause signal fluctuation and make the system oscillate. Frequency converter and control cabinet should be electrically connected. If the actual installation is difficult, copper wires can be used for jumper.
Lightning protection In the frequency converter, a lightning absorption net is generally provided, mainly to prevent the instantaneous lightning from invading and damaging the frequency converter. However, in practical work, especially in the case of overhead introduction of power lines, the absorption network of frequency converters alone can not meet the requirements. This problem is particularly important in areas where lightning is active. If the power supply is overhead incoming line, a special lightning arrester for frequency conversion should be installed at the incoming line (optional), or a steel pipe should be embedded 20m away from the frequency converter for special grounding protection according to the requirements of the specification. If the power supply is introduced by cable, the lightning protection system in the control room should be done well to prevent lightning from entering and damaging the equipment. Practice shows that this method can basically solve the lightning strike problem effectively.
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