"General" VFD or "Vector" VFD????

[rbertalotto]

Last question, I promise!

The VFD I'm looking at in a ChiCom unit. Very inexpensive but has 359 positive reviews and lots of YouTube support and folks comment that the customer service is outstanding.....So for a small home shop, the price is right. (Under $100)

But they offer a "General VFD" and a "Vector VFD" for basically the same price.

Why one over the other?

 

[rabler]

Well, marketing can apply terms in completely random fashion, so without asking the vendor, you really can't tell.

Technically, VFD's generally have two modes of control. V/f is the more simplistic mode, where the voltage is reduced when the frequency is reduced below 60 Hz to prevent overdriving the motor. The more sophisticated mode is often called "sensorless vector control". In this mode, the VFD attempts to use a sophisticated control algorithm based on the magnetic flux parameters of the motor. This requires "tuning" the VFD to the motor, where the VFD runs the totally unloaded motor through various paces to determine how the motor responds. This gives better control of the motor, especially at lower RPM. Most modern VFDs are programmable to select between these two modes.