The VFD is an electrical control device that uses variable frequency and microelectronics technology to control the power of an AC motor by changing its working frequency. It is mainly composed of rectification (AC to DC), filtering, inverter (DC to AC), braking unit, drive unit, detection unit, microprocessing unit, and other components. The VFD adjusts the voltage and frequency of the output power supply by controlling the opening and closing of the internal IGBT, providing the required power voltage for the motor according to its actual needs, thus achieving energy saving and speed control. Additionally, the variable frequency converter also has many protection functions, such as overcurrent protection, overvoltage protection, overload protection, etc. With the continuous improvement of industrial automation, the variable frequency converter has been widely applied.
Temperature impact: When selecting a VFD, the ambient temperature should be taken into account. The general operating temperature ranges from -10°C to 40°C. If the working temperature exceeds 40°C, the VFD should be derated by 5% for every 1°C increase. For every 10°C increase in the working temperature, the lifespan of the variable frequency converter is halved. Therefore, the surrounding environment and heat dissipation of the VFD must be properly addressed.
Humidity impact: When selecting a variable frequency converter, if it operates in an environment with a relative humidity of less than or equal to 90% and without condensation, it is considered suitable. In high humidity conditions with significant humidity fluctuations, condensation may occur inside the VFD, which can greatly reduce the insulation performance and even cause a short circuit. If necessary, desiccants or heaters must be added to the enclosure.
Altitude impact: A VFD installed at an altitude below 1000m can output its rated power. When the altitude exceeds 1000m, the output power will decrease.
Dust impact: It is not advisable to install a variable frequency converter in environments with conductive metal dust. Conductive dust can penetrate the internal components of the VFD, causing internal circuit shorts and potentially damaging the VFD. This must be considered when selecting a VFD.