Constant Pressure Water Supply of VFD

A variable frequency drive (VFD) is a type of motor controller that drives an electric motor by varying the frequency and voltage of its power supply. The VFD also has the capacity to control ramp-up and ramp-down of the motor during start or stop, respectively. Even though the drive controls the frequency and voltage of power supplied to the motor, we often refer to this as speed control, since the result is an adjustment of motor speed. In this article, we will test VFD constant pressure water supply system.

We mainly use 4 ports, COM, GND, CI, 24V. We also need to connect JP3 to the I side and a 4-20mA water pressure sensor. First, connect red to 24V port, connect green to CI, the ATO VFD part model 24V port identification is P24. The 24V port of some ATO VFDs is labeled P24. We will use a bucket of water for pressure testing.

To prevent parameter interference, you can restore the VFD parameters first (not necessary steps). P3.01=10. Restart after power off. Set the pressure gauge range (pressure sensor range) parameter P7.27, MPa.

Switch b-15 to view the current feedback pressure. Set other parameters, where the parameter with * is the key parameter. Pressure and time related parameters are set according to your needs.

Start VFD. Lift the pressure sensor to reduce the pressure it receives. After decreasing to a certain extent, the VFD starts and the frequency rises to the motor running frequency. Check the feedback pressure b-15, the current pressure is less than the set target pressure P7.05 (0.18MPa). After increasing pressure to the sensor, check the VFD running frequency. The VFD first drops to Hibernation frequency P7.22 (30 Hz) and then drops to 0 Hz. The current pressure of 0.21 MPa is greater than the target pressure of P7.05 (0.18 MPa).

Demonstrate again. When the pressure is reduced, the VFD operates at the rated frequency of the motor. When the motor pressure increases, the VFD operates at the Hibernation frequency (P7.22=30 Hz). After reaching the set time, the VFD output frequency drops to 0 Hz.

If you want to learn more about VFD constant pressure water supply system, please click this video or contact us.