How to Control the Speed of VFD?
Variable frequency drive (VFD) is an electric power control equipment that uses frequency conversion technology and micro-electronic technology to control ac motors by changing the frequency of the motor's working power supply.
VFD is mainly composed of rectifier (AC to DC), filter, inverter (DC to AC), brake unit, drive unit, detection unit and micro-processing unit. Variable frequency drive by internal IGBT off to adjust the voltage and frequency of the output power supply, according to the actual needs of the motor to provide the required power supply voltage, so as to achieve the purpose of energy saving, speed regulation. In addition, VFD also has many protection functions, such as over current, over voltage, overload protection and so on. With the continuous improvement of industrial automation, frequency converter has been widely used.
ATO provides many types of high quality variable frequency drives, taking the three-phase VFD as an example to say how to control the speed.
Three-phase motors run at different speeds in different time periods, which makes use of the multi-speed operation mode of the VFD.
Multi-speed control requires COM, X1~X4, FWD and REV ports. Inside and outside also need to use a three-switch button box, forward start self-lock button, pause button.
To set the following parameters before using it. As shown in the figure.
Press the FWD button and the motor runs at the frequency set by P0.02. (Setting method: first set P0.01, and then set P0.02)
K1～K3(X1～X3) have seven different combinations, so it can set seven different running speeds.
The acceleration/deceleration time of the motor is combined by P4.00=6～8 corresponding to P4.0=1～3. To completely stop the motor, disconnect the forward input FWD (reverse REV).
Choose the type of variable frequency drive, according to the type of production machinery, speed range, static speed accuracy, starting torque requirements, decide to choose which control mode of VFD is the most appropriate. To learn more about three-phase variable frequency drive, click on the video below.