For the inverter, the most popular electrical control device at present, as a precision electronic industrial control device, in order to make the inverter run smoothly and normally for a long time, as professional technicians, we also need to install or operate the inverter. Before, start from the four environmental factors that directly affect the operation of inverter high quality, and do a good job in preparation.
1. The physical environment of the frequency converter
(1) Temperature factor
Temperature has a huge impact on the life and reliability of the electronic components inside the inverter. When using the inverter in an environment with high operating temperature, additional cooling measures must be taken to ensure that the ambient temperature is stable within the range required by the inverter manual (-10～+40/45℃). In the electric control box, the inverter should generally be installed on the upper part of the box, and it is strictly forbidden to install the heating element close to the bottom of the inverter! In addition, the inverter's own cooling fan should be checked and cleaned regularly during use.
(2) Humidity factor
For the harm of such factors, I believe that the majority of colleagues can understand that when the ambient humidity is greater than 90%, the insulation of the components inside the inverter will deteriorate, which will lead to the failure of the inverter. Therefore, if necessary, putting a desiccant in the inverter becomes a necessary dehumidification means.
(3) Corrosive gases
Since the corrosive gas has a great effect on the electrical insulation performance of the internal PCB board and plastic product casing of the inverter, the inverter should be used in such an environment with a sealed casing that meets the requirements of safety regulations.
(4) Vibration and shock
These two physical phenomena will cause poor electrical contact of the inverter and open welding of components, and also have a great impact on the normal use of the inverter. Therefore, it should not be careless to strengthen the daily maintenance and repair work.
2. The electrical environment of the frequency converter
(1) Prevent electromagnetic interference
Due to the existence of rectification and inverter links in the work of inverter high quality, a lot of electromagnetic wave interference is bound to occur during this working process, and these high-frequency electromagnetic waves have certain interference to nearby instruments. For this reason, the instruments and meters on the same network as the inverter should be grounded first, and cables with shielding layers should be used for the connection between various electrical components and instruments, and the shielding layer must be grounded.
(2) Prevent overvoltage at the input terminal
Although most frequency converter power input terminals have over-voltage protection function, if the high voltage at the inverter input terminal acts for a long time, the related components inside the inverter will often be damaged. For power supplies with frequent power supply voltage fluctuations and large amplitudes, consider using voltage regulators.
3. Frequency converter grounding
The correct grounding of the inverter is an important means to improve the sensitivity of the system and suppress noise interference. The grounding resistance of the grounding terminal G of the inverter should be as small as possible. The cross-sectional area of the grounding wire should not be less than 2mm², and the length should be controlled within 20m. In addition, it should be pointed out that the shielding layer of the inverter high quality signal input line should be connected to the G (or E) terminal, and the other end must not be connected to the ground, otherwise the signal will fluctuate and the system will oscillate.
4. Frequency converter lightning protection
There are generally lightning absorption and discharge circuits in the inverter to prevent the inverter from being damaged due to instantaneous lightning intrusion. Unfortunately, in the actual operation process, especially when the power cord of the inverter is introduced overhead, it is far from enough to rely solely on the lightning protection circuit inside the inverter. For this reason, in the lightning active area and the inverter power supply is introduced by the overhead line, a special lightning arrester for the inverter should be installed at the incoming line, or a special grounding protection device for galvanized steel pipe should be embedded 20m away from the inverter according to the specification requirements. Lightning protection.